BCLN BIOLOGY 11 – Rev July 2014
Unit 3 ~ Learning Guide
Name: _______________
INSTRUCTIONS
Using a pencil, complete the following notes and questions as you work through the
related lessons. You are required to have this package completed BEFORE you write
your unit test. Do your best and ask questions about anything that you don't understand
BEFORE you write the unit test.
3.1 NOTES: INTRODUCTION TO ECOLOGY
YOU SHOULD WATCH THE IMPORTANCE OF BIODIVERSITY
VIDEO BEFORE PROCEEDING ANY FURTHER!
What is Ecology?
Ecology is __________________________________
___________________________________________
_____________________. In other words, ecology
has to do with the _____________________________
_____________________________ and with how the
___________________________________________
____________________________________ parts of
an environment fit together and how one affects the
other.
Ecologists often study _________________________
______________________. An ecosystem is _______
___________________________________________
___________________________________________
________________________________.
Ecosystems can cover large areas, such as the brush grasslands of the Central
Okanagan Valley or the coastal Douglas fir ecosystems on Vancouver Island.
Ecosystems can also be small, such as a single tide pool or a rotting log. Ecosystems
are made up of _______________________________________________________.
The biotic and abiotic components of an ecosystem are closely tied.
______________________________________________________________________
______________________________________________________________________
_______________________________________ Different kinds of organisms play
different roles in the environment. Plants make usable energy from sunlight and basic
nutrients, animals consume the plants, other animals may consume those animals, and
if any of these organisms die, bacteria and fungi are largely responsible for breaking
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BCLN BIOLOGY 11 – Rev July 2014
down and using the nutrients that were once used by the organism and returning them
to the earth. These nutrients can then again be used by the plants. ________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
____________________________________________________.
When
studying
ecosystems we must look at all of the interactions of all of the components of that
ecosystem.
Ecologists seek to explain:
 Life _____________________________________________________
 _________________________________________________ of organisms
 the movement of materials and energy through living communities
 the _________________________________________________________, and
 the ___________________________________________________________ in
context of the environment.
Levels of Organization
Where does the ecosystem fit within the various levels of organization?

The Biosphere
The
biosphere
is
the
______________________________________
_____________________ of organization. The biosphere is a thin layer around
the earth that includes ________________________________________.
This thin layer includes the _______________________________________
________________________________________. Most organisms live within
the first few meters of the surface of land and oceans. The biosphere has been
divided into distinct regions based on the dominant forms of plant life and
prevailing climate. These regions are referred to as Earth's biomes.
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BCLN BIOLOGY 11 – Rev July 2014

The Ecosystem
There are many ecosystems within each biome. Ecosystems include the
________________________________________________________________
________________________________ in a particular place. Example: A pond.
The pond contains a variety ______________________________________
_________________________________. These organisms interact in ways that
affect their survival. They are all a part of the pond food web. ________________
_________________________________________________________________
_________________________________________________________________
_________________________________________________________________
_________________________________________________________________
_________________________________________________________________

Communities
Communities are defined as ______________
__________________________________________
__________________________________________

Populations
Populations are defined as ____________________
__________________________________________
__________________________________________

Organism
This is the simplest level of ecological organization. Organism refers only to the
_____________________________________. Research at this level involves
things like adaptations.
This is what the levels of organization
look like: Note the location of the
ecosystem in this hierarchy.
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BCLN BIOLOGY 11 – Rev July 2014

Niche
Although not part of the level of organization __________________________
______________________________________________________ extremely
important and ____________________________________________________.
A way of life. The organisms JOB in its habitat!
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
___________________________________ all contribute to its niche.
Here are a few important definitions:
o ______________________________________: The range of conditions a
species can potentially tolerate and the range of resources it can
potentially use.
o ______________________________________: The range of resources
the species actually uses.
Any differences between the fundamental and realized niches are due to
___________________________________________________________
__________________________________________________________.
o ______________________________________: tend to have broad
niches as they can tolerate a wide range of conditions and use a variety of
resources.
o ______________________________________: have a narrower niche as
they tend to operate in more specific conditions and use specific
resources.
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BCLN BIOLOGY 11 – Rev July 2014
YOU SHOULD WATCH THE BASIC ECOLOGY
VIDEO BEFORE PROCEEDING ANY FURTHER!
Human Impact
Human presence has _____________________
_________________________________. Humans
change existing ecosystems. The human increase
in population threatens the stability and diversity of
the planet.
It is ironic that this instability threatens the human
population itself. For example, the destruction of
the rain forest may lead to an increase in carbon
dioxide which raises the world temperature. _____
_______________________________________
__________________________________. Many
of these organisms are needed for humans to
survive.
It is estimated that there are over _____________
_______________________________. Only 2
million have been identified. __________________
_________________________________________
_________________________________________
_________________________________________
and the development and over harvesting natural resources. Extinction occurs naturally
but
____________________________________________________________
_____________________________. The extinction of species reduces valuable
resources available to humans.
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BCLN BIOLOGY 11 – Rev July 2014
3.1 PRACTICE: INTRODUCTION TO ECOLOGY
1. Please relate organism to population to community to ecosystem to biosphere. (5
marks)
2. A (an) __________________________ is when populations within a community
interact with one another and the environment. (1 mark)
3. All organisms that live in one common
_____________________________. (1 mark)
area
make
up
a
(an)
4. When many populations live together it is called a (an) ____________________.
(1 mark)
5. All living things on earth make up the ___________________________. (1 mark)
6. When the human population increases in size the ecosystem becomes
___________________________. (1 mark)
7. Burning fossil fuels produces a mass amount of Carbon Dioxide. The
____________________________ is able to filter the majority of this waste. (1
mark)
8. A (an) ___________________________ is many animals that have similar
characteristics and has the capability to produce offspring. (1 mark)
9. When the environment changes and the members of species are unable to adapt
to
the
change,
the
outcome
will
most
likely
lead
to
_____________________________. (1 mark)
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BCLN BIOLOGY 11 – Rev July 2014
3.2 NOTES: ENERGY FLOW IN ECOSYSTEMS
Food Chain versus Food Web
There are many relationships within a given ecosystem. Perhaps the
most
obvious
type
of
relationship
is
a
___________________________________.
We
can
use
______________________________________________________
______________________________________________________
______________________________________________________
_______________________________________. A food chain is a
______________________________________________________
_______________________________________________________
_______________________________. Food chains simply describe
________________________________________________. They
______________________________________________________
___________ in an ecosystem, _____________________________
________________________. They are useful for looking at simple
relationships between specific members of an ecosystem.
In reality, ______________________________________________
_________________________________________. This network is
___________________________________. Food webs more clearly
______________________________________________________
_________________________. The more organisms that are
included, the more complex the food web becomes. You should note
that the arrows in a food chain or web _______________________________________
_________________________________________________________.
In other
words, you could replace the arrow with the words "__________________________.”
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BCLN BIOLOGY 11 – Rev July 2014
Feeding relationships are only a small portion of the many types of relationships that
exist in ecosystems. The components of ecosystems interact with each other in many
complex ways. _________________________________________________________
________________________________________________________________. Some
organisms work together to achieve common goals. Climatic variations, natural
disasters, and human activities all affect the organisms in an ecosystem. ____________
______________________________________________________________________
_________________________________________________. This energy originates
from the sun.
Organism
algae
Trophic Type
primary producer
Prey/Food
---
birds
carnivorous
consumer
planktivorous
consumer
omnivorous
consumer
top consumer
krill, fish
Predators/Grazers
krill, fish, blue
whales
seals, killer whales
algae, krill
killer whales
algae, krill
birds, seals, killer
whales
---
blue whales
fish
killer whales
krill
seals
herbivorous
consumer
carnivorous
consumer
blue whales, fish,
birds, seals
algae
fish, birds
fish, blue whales,
birds
killer whales
Flow of Energy
_________________________ is the ultimate source of energy
for all living things. How does energy flow through an ecosystem?

Producers are _________________________________
______________________________________________
______________________________________________
________________________________________. These
organisms are _______________________ because they
make their own food. Examples of autotrophs are plants,
photosynthetic bacteria, and algae.

Consumers are _________________________________________________
__________________________________________________________. These
organisms that eat other things are called _________________________.
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BCLN BIOLOGY 11 – Rev July 2014
Following is an explanation of the various levels of consumers.
o Primary consumers, called __________________
___________________________________. A cow
eating grass would be an example.
o Secondary consumers can be ______________
________________________________________
______________________________. A bear
would be a good example for the omnivore as they
can eat various berries or fish.
o Tertiary consumers at the top of the food chain
________________________________________.
A cougar is only one example of a tertiary
consumer.
o Decomposers
__________________________
__________________________. ______________
________________________ are examples of
decomposers. It is estimated that each acre of soil
has 1 ton of active bacteria.
Energy Pyramids and Energy Flow
The idea of a food web is fairly simple.
Most students are familiar with the
idea that plants produce energy from
the sun by photosynthesis, animals eat
plants, other animals eat those
animals, and the dead organisms are
decomposed by detritus (bacteria and
fungi). The different viewpoint here is
that __________________________
_______________________________
___________________ in the food
web.
In a food web the direction of the __________________________________________
___________________________________. Because _________________________
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BCLN BIOLOGY 11 – Rev July 2014
______________________________ (the transfer is not 100% efficient) ____________
______________________________________________________________________
_______________________________________________________________. This is
the concept of a ______________________________________.
Each level of the pyramid is referred to as a _______________________________ and
______________________________________________________________________
______________________________________________________________________
_____________________. There is generally a _____________________________ of
the food chain.
This energy loss can be depicted using an ___________________________________.
Notice the pyramid is ___________________________________________________
_________________________________________________. The mass (weight) and
numbers of organisms ___________________________________________________.
In an Ocean Energy Pyramid it takes about 1000 kilograms of phytoplankton to support
0.2 kilograms of tuna (1 can).
YOU SHOULD WATCH THE TROPHIC RELATIONSHIPS
VIDEO BEFORE PROCEEDING ANY FURTHER!
The Role of Photosynthesis and Respiration
If the sum is the ultimate source of energy for all organisms then how is that energy
captured? The suns energy is captured by producers in a process called
photosynthesis. Photosynthesis is the ______________________________________
___________________________________________________________________
____________________________________________________. In plants, this
process occurs in specialized cell organelles called ______________________.
Photosynthesis is the process that _________________________________________
__________________________________ that is the base of the energy pyramid.
The chemical reaction that takes place in chloroplasts (say inside a tree leaf) uses the
light energy from the sun to convert ________________________________________
____________________________________________________________________
____________________________________________________________________
.
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BCLN BIOLOGY 11 – Rev July 2014
Cellular respiration is the ________________________________________________
____________________________________________________________________
________________________________________ (adenosine triphosphate) that can
do work inside cells. This process occurs in specialized cell organelles called
________________________.
The chemical reaction that takes place in mitochondria (say inside a muscle cell) uses
______________________________________________________________________
______________________________________________, the energy currency of cells.
It is important to note that _______________________________________________
_____________________________________________________________________
_____________________________________________________________________
______________________________________________
.
As well as being transferred as an energy source, carbon transfers between organisms
through photosynthesis and respiration. ____________________________________
___________________________________________________________________
___________________________________________________________________
________________________________________________________. When an
organism dies and is broken down this carbon is again released in its simple form of
carbon dioxide. Respiration also gives off carbon dioxide. The carbon cycle is of
environmental concern because the destruction of forests and the burning of fossil fuels
is increasing the amount of carbon in the atmosphere. __________________________
______________________________________________________________________
______________________________________________________________________
____________________________________.
Bioaccumulation
___________________________________________________
___________________________ such as petroleum-based
pesticides, and other toxins, ______________________. When
a consumer eats these toxins, ___________________________
___________________________________________________
____________________________. Bioaccumulation then is
the increase in concentration of a substance in living organisms
as they take in contaminated air, water, or food.
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BCLN BIOLOGY 11 – Rev July 2014
Bioaccumulation is a problem in the north because of higher concentrations of toxic
pollution. Also, northern animals have a lot of fat to keep them warm, toxins accumulate
mostly in fat.
Biomagnification
When such a _____________________________
__________________________________________
__________________________________________
_______________________________.
See
the
example beside of the increase in DDT concentrations
as we move up tropic levels. Note that organisms at
the top of the food chain have the highest level of
biomagnification. In other words, the higher the
trophic level the greater the risk of fat-soluble toxin
acquisition and concentration in the tissues.
3.2 PRACTICE: ENERGY FLOW IN ECOSYSTEMS
1. Please compare and contrast food chains and food webs. (3 marks)
2. Please write the chemical equation for:
a. photosynthesis and identify which organelle performs this process. (2
marks)
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BCLN BIOLOGY 11 – Rev July 2014
b. cellular respiration and identify which organelle performs this process. (2
marks)
3. Please compare and contrast photosynthesis and cellular respiration with respect
to energy flow, purpose, and organisms involved. (6 marks)
4. Please explain, with respect to energy flow and the concept of biological
pyramids, why there is always fewer numbers and less biomass at the top of a
food pyramid. (3 marks)
5. Please explain the difference between bioaccumulation and biomagnification. (3
marks)
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BCLN BIOLOGY 11 – Rev July 2014
3.3 NOTES: SYMBIOSIS
What is Symbiosis?
The word symbiosis comes from the Greek roots "sym" meaning _________________
and "biosis" meaning _________________________. Symbiosis describes situations in
which animals live with each other.
Whenever two organisms of different species __________________________________
___________________________ often but not always to the benefit of both organisms,
that's symbiosis. Symbiosis can occur between ______________________________
______________________________________________________. Some symbiotes
are so closely intertwined that it's difficult to tell where one organism ends and the other
begins. And in the case of plant/animal symbiotes, it can be difficult to tell whether the
organisms are plants, animals, or a little bit of both.
There are three main types of symbiosis;
1. ________________________________________
2. ________________________________________
3. ________________________________________
1. Parasitism (+/-)
In parasitism the __________________________________________________
_____________________________. Parasitism does not often result in
immediate death of the host organism. There are two types of parasites:
a. Ectoparasites: __________________________ – ticks, fleas, leeches.
Endoparasites: _________________________ – bacteria, protists, worms.
2. Commensalism (+/0)
In biology, commensalism is a relation between individuals of two species in
which one species obtains either nutrients, shelter, support, or locomotion from
the __________ species, which ___________________________________.
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BCLN BIOLOGY 11 – Rev July 2014
The commensal relation is often between a larger host
and a smaller commensal; the host organism is
unmodified, whereas the commensal species may
show great structural adaptations.
A commensal relation based on shelter is seen in
_________________________________________
_________________________________________
____________________________, where they are
protected from predators. In another example
_________________________________ often follow
cattle and __________________________________
________________________. __________________
from the cow without injuring the cow. However, ____
___________________________________________
_________________ from the egret.
3. Mutualism (+/+)
Mutualisms are ecological interactions between two
species ____________________________________
______________________. A species may be so
dependent that it cannot ______________________
________________________. In other cases, a
species can interact mutualistically with more than one
partner or even live without its partner(s) under certain
conditions. Although ________________________
__________________________________________________________, we still
expect each species to be "selfish" and to evolve traits that provide the maximum
possible fitness benefit while minimizing cost.
An example of mutualism takes place between Ants and Bull’s horn. Ants get
food from the shrub and in return protects the shrub from herbivores.
_________________________________________________________________
__________________________________________________________.
The
pollinators obtain nutrients from the flowering plants and in turn, carry the pollen
from one plant to another for plant fertilization. Flowers lure pollinators with
_______________________________________________________________.
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BCLN BIOLOGY 11 – Rev July 2014
3.3 PRACTICE: SYMBIOSIS
1. Please complete the following table on symbiosis. (10 marks)
Symbiosis:
An interaction between two different organisms living in close physical
association where at least one organism benefits from the relationship.
mutualism
commensalism
Definition
Symbolic
+/+
Representation
Facial
/
Representation
Example
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parasitism
BCLN BIOLOGY 11 – Rev July 2014
3.3 NOTES: PROPERTIES OF POPULATIONS
What is a population?
A population is _________________________________________________________
______________________________________________________________________
_____________________________. A population can be defined by any boundary. For
example we could talk about the population of humans at your school, the population of
your city, the population of your province, etc.
When scientists study populations they focus on the population as a whole, and look at
characteristics such as _______________________________________________
______________________________________. These characteristics help determine
the size of the population. Recent consensus for the world's human population is that
humans have now reached 7 billion!!!
Sometimes population size is easy to measure (example:
trees and plants).
In other situations it is difficult to measure the population
size. This would occur when an animal is ________
______________________________________________
_______________________________________. In these
situations, estimates of population size are made.
YOU SHOULD WATCH THE POPULATION ECOLOGY
VIDEO BEFORE PROCEEDING ANY FURTHER!
Population Density
Population density is ____________________________________________________
____________________________________. It is expressed as the number of
individuals per unit area or volume.
 Example: the population density of humans in the US is about ______________
___________________________________
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BCLN BIOLOGY 11 – Rev July 2014

Example: the population density of humans in Japan is about _______________
_____________________________________
When considering population density the population's __________________________
________________ needs to be considered. Dispersion describes the _____________
_________________________________________________________. Dispersion
patterns will depend on the scale at which you observe the population and there are
three basic types of dispersion patterns.
1. Clumped Distribution:
_______________________________
_______________________________
_______________________________
_____________. Can also occur due to
_______________________________
______________________.
Examples: Zebras in herds, birds in
flocks.
2. Even Distribution (uniform).
_______________________________
_______________________________
________________________. Usually
individuals try to get as far away as
possible from each other ___________
________________________________
_______________________________.
3. Random Distribution.
_______________________________
_______________________________
_______________________________
Random
dispersal
of
organisms
_______________________________
_______________________________
___________________________________________________________.
Example: seed dispersal is by the wind and birds.
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BCLN BIOLOGY 11 – Rev July 2014
Population Dynamics
___________________________ is the amount by which a population’s size changes
in a given time. All populations are _________________________________________
____________________________. Whether a population grows, shrinks, or remains
the same size depends on four processes: __________________________________
____________________________________________.
The dynamics of a population are also determined by other factors such as Life
Expectancy (___________________________________________________________
___________________) and Age Structure (__________________________________
______________________________________). For example, important population
processes vary with age. Very old individuals _________________________________.
Populations with a _______________________________________________________
________________________________________________. This scenario changes for
different species as their rate of survival at different stages in life varies. A
_________________________________ is used to illustrate the likelihood of the
survival of different species at different ages.

Type I survivorship curve.
Humans and elephants _______________________
_______________________
_______________________

Type II survivorship curve.
Some birds - _____________
_______________________
_______________________
_______________________

Type III survivorship curve.
Oysters, salmon, & insects ________________________________________________________________
________________________________________________________________
________________________________________________
Population Growth Rate
Populations of organisms change in number over time. _________________________
____________________________________________________________________
_______________________________________________________. This may result
in the complete elimination of a population of organisms or possibly the _____________
________________________________________________________.
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BCLN BIOLOGY 11 – Rev July 2014
.
As previously stated, whether a population grows, shrinks, or remains the same size
depends on four processes: ________________________________________________
_________________________________________________




Births (b) = _______________________________________________________
Deaths (d) = _____________________________________________________
Emigration(e) = __________________________________________________
_______________________________________________________________
Immigration(i) = ___________________________________________________
________________________________________________________________
When a population changes in number we can calculate its ______________________
using the following equation:
r = (( b + i ) - (e + d)) / n
In order to figure out the growth rate(r) of a certain population, ___________________
_____________________________________________ must be added together
first.
These
are
the
immigrants
(i)
and
the
births
(b).
Next,
_________________________ ___________________ are subtracted. These are the
emigrants (e) and the deaths (d). This number is then divided by the total number of
organisms in the initial population (n).
A ___________________________________________ from the formula means _____
___________________________________________, while a ___________________
________________________________ means that ___________________________
______________________________________.
3.3 PRACTICE PART 1 of 2: PROPERTIES OF POPULATIONS
1. Please define population. (1 mark)
2. Please define population density. (1 mark)
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BCLN BIOLOGY 11 – Rev July 2014
3. Please identify and describe the three patterns of population dispersion.
marks)
(3
4. Please identify and describe the three patterns of survivorship curves. (3 marks)
5. If a population of 5000 plants is on an isolated island (no immigration or
emigration), and 400 new plants are sprouting in the population for every 200 that
are dying:
a. What is the growth rate of the population? (3 marks, 1 each for ESE =
Equation, Substitute, Evaluate)
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BCLN BIOLOGY 11 – Rev July 2014
b. How many plants would there be after 3 years at this growth rate? (3
marks, 1 each for ESE = Equation, Substitute, Evaluate)
6. If a population of 10 000 mice are on the island, and 40 swim off the island while
50 swim on, and 5000 mice are born in the population for every 6000 that are
dying:
a. What is the growth rate of the population? (3 marks, 1 each for ESE =
Equation, Substitute, Evaluate)
b. How many mice would there be after a period of 2 years? (3 marks, 1 each
for ESE = Equation, Substitute, Evaluate)
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BCLN BIOLOGY 11 – Rev July 2014
Models of Population Growth
When studying how populations grow scientists have developed two basic models to
describe how a population might change over time as it grows.
1. The Exponential Model (J curve)

The Exponential Model _____________
_________________________________
_________________________________
__________________. The larger the
population gets the faster it grows. It is
assumed that the birth rate and death
rates
remain
constant
and
that
________________________________
________________________________
________________________________.

Predictions
Model.
Based
on
Exponential
The graph of exponential growth shown below has a characteristic Jshaped curve. Something is said to increase or decrease exponentially if
its rate of change must be expressed using exponents. A graph of such a
rate would appear not as a straight line, but as ______________________
___________________________________________________.
As this model indicates, _______________________________________
________________, but, ______________________________. We can
use this model to predict that the population will grow indefinitely and at an
increasingly rapid rate.

Limitations of the Exponential Model.
How well does it match the growth pattern of real populations? Real
populations _________ grow like this, but under rare conditions and for
only _______________________________. In reality, the population will
____________________________________________________________
________________________________. There will be a ______________
_________________________________________________________.
2. The Logistic Model (S curve)

The Logistic Model builds on the exponential growth model and
_______________________________________________________
_______________________________________________________
_______________________________________________________
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BCLN BIOLOGY 11 – Rev July 2014
____________________. This model incorporates some new terms:

Carrying capacity (K) ________________________
________________________
________________________
________________________
________________________

Steady State - ____________
________________________
________________________
___________________________________________________________
___________________________________________________________

When the population size is small and resources are abundant, the birth
rates are high and death rates are low. As the population grows it hits a
period of _____________________________________. As the population
reaches the ecosystem's ______________________________, the
growth rate slows resulting from_________________________________
___________________________________________________. For all
populations at carrying capacity the birth rate equals the death rate. This
population is said to be at a __________________________ where the
__________________________________________________________
_________________________________________. This may be the
result of reaching the carrying capacity of the environment or in response
to other limiting factors.

Limitations of the Logistic Model:
The logistic model assumes the carrying capacity remains constant.
_______________________________________________________
_______________________________________________________
_______________________________________________________
______________________________________________. In response
population sizes will also fluctuate.
Population Regulation
There are many factors that affect immigration, emigration, births and deaths and
consequently the population growth rate. These factors can be categorized into two
groups of limiting factors:
1. ______________________________________________ or
2. _______________________________________________
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BCLN BIOLOGY 11 – Rev July 2014
1. Density-independent factors.

It has been observed that when there are _________________________
__________________________________________________________
__________________________________________________________
__________________________________________________________
__________________________________________________________
_________________________________. Therefore, abiotic factors are
density-independent.

Examples: Weather, floods, fires, cold-snap. These factors reduce the
population size by the same proportion__________________________
___________________________________.
2. Density-dependent factors.

__________________________________________________________
__________________________________________________________
__________________________________________________________
_____________________. Therefore, they are termed density-dependent
factors.

When populations become crowded organisms have to compete with one
another for resources such as food, water, space, mates etc. Competition
among members of the same species is a density-dependent limiting
factor. The more individuals there are the faster resources become
limited.

Competition between members of different species is a major force
behind evolutionary change. In this case competition results from
_____________________________________________. This is when
two or more species __________________________________________
_______________________ and ____________________________
____________________________. When two species compete, both
find themselves under pressure from natural selection to change in ways
that reduces their competition.

Example: Darwin's finches - Several species of birds eat a different size
seed.

Example: Resource limitations - lack of food. ______________________
_________________________________________________________

Density dependent factors will _________________________________
_________________________________________________________
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BCLN BIOLOGY 11 – Rev July 2014
Cyclic Population Fluctuations
All populations ______________________________________. Some of these
fluctuation are ___________________________________________________________
______________________________________________________________ linked to
fluctuations of predator/prey populations within a given ecosystem.

Example: ____________________
Population numbers fluctuate due to
predator-prey interactions. _______
____________________________
____________________________
____________________________
____________________. However,
there will soon be ___________
_________________ and as a
result of the increased predation,
the hare population will decrease.
____________________________
____________________________
________________________________________________________________
________________________________________________________________.
This decrease in lynx population is good for the hare and hare numbers will
increase again. This increase will be followed, with a _________,
__________________________________________________, leading to a
decrease in hare, then a decrease in lynx, and so on. This growth pattern will
continue with all populations even if fluctuations are slight. ________________
____________________________________________________________
_________________________________________________________.
Adaptations in Predator-Prey Relationships
Natural selection favours adaptations that ________________________________
______________________________ and the _______________________________
___________________________. This concept explains many of the interesting
features seen amongst organisms. Some examples are: a rattlesnake's keen sense of
smell, a spider's webs, sharp teeth in wolves as well as _____________________
________________________________________, thorns in plants and chemical
deterrents found in poison oak.
Perils of small populations
It
is important
to
note that
_________________________________________
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BCLN BIOLOGY 11 – Rev July 2014
______________________________________________. Environmental disturbances
such as storms, fires, floods, or disease can have dramatic effects on small populations.
Disease outbreaks can wipe out the entire population. In small populations inbreeding is
more likely to occur. When this occurs the offspring of related parents often have fewer
offspring, are more susceptible to disease, and have a shorter life span. Inbreeding will
also often lead to diseased genetic variability and may reduce the population's ability to
adapt.
Be sure that you understand that a species ability to survive is based on its biotic
potential. Biotic potential is _____________________________________________
__________________________________________________________________. Full
expression of the biotic potential of an organism is restricted by __________________
__________________________________________________________________
__________________________________________________________________
__________________. It is generally only reached when environmental conditions are
very favorable. A species reaching its biotic potential would exhibit ________________
__________________________________________________________________
_______________ that is, how many offspring are produced per mother.
3.3 PRACTICE PART 2 of 2: PROPERTIES OF POPULATIONS
1. Scientists model population growth in many ways:
a. Please compare and contrast the exponential growth model and the
logistic growth model. It is ideal to draw the graphs (make sure they are
appropriately and completely labelled) and then to explain what each
curve is representing. (6 marks)
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b. What model is the better representation of growth in the vast majority of
populations? Why? (2 marks)
2. Population growth can be influenced by density-independent factors and densitydependent factors.
a. Please give an example of a density-independent factor and how it
influences population growth. (1 mark)
b. Please give an example of a density-dependent factor and how it
influences population growth. (1 mark)
3. Using pictures/symbols and as few words as possible (this is a critical-thinking
challenge) clearly explain cyclic population fluctuations amongst predators and
their associated prey. (3 marks)
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BCLN BIOLOGY 11 – Rev July 2014
3.4 NOTES: SUCCESSION
What is Succession?
Just as the people living in your neighborhood can come and go, _________________
_____________________________________________. One way a community
can change is if external conditions shift. If the weather in a certain geographical area
suddenly gets colder, certain populations will be better off and will thrive, while others
will shrink and disappear.
However, change in communities is not always caused by external factors;
______________________________________________________________________
____________________. The success of a particular population in a particular area will
change the environment to the advantage of other populations. In fact, the originally
successful population often changes the environment to its own detriment. In this way,
the populations within a community change over time, often in predictable ways.
___________________________________________________________________
___________________________________________________________________
____________________________________________. Successional change in a
community is the ______________________________________________________
___________________________________________________________.
Succession can either begin with Primary Succession, which is __________________
______________________________________________________________________
______________________________________________________________________
____________________________________________, or Secondary Succession,
which is _______________________________________________________________
____________________________________________________ (natural disaster like a
forest fire or human activities such as logging). Primary Succession takes much longer
(centuries) than Secondary succession (decades).
Succession begins when populations move into geographic areas. _________________
_________________________________________________ is referred to as a pioneer
species. If this pioneer population is successful in its new location, it will change the
environment in such a way that new populations can move in (Intermediate species).
This will continue until eventually, the community reaches a point where the mixture of
populations creates no new changes in the environment. At this point, ______________
______________________________________________________________ are said
to make up a climax community. While individuals within a climax community will
come and go, ______________________________________________________
_________________________________________________________________
________________________________________________________________.
.
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BCLN BIOLOGY 11 – Rev July 2014
YOU SHOULD WATCH THE ECOLOGICAL SUCCESSION
VIDEO BEFORE PROCEEDING ANY FURTHER!
Succession in Action
Imagine a catastrophic event: a forest fire rages
through the Okanagan Mountain Park of British
Columbia. The fires burn everything and leave
behind a barren, rocky expanse. The population of
trees that once lived in this area can’t grow back
because the fire has changed the ground
composition. This rocky ground, however, proves
ideal to lichens, the ________________________
_____________________. The lichens colonize
the rocks and thrive. As part of their life process, lichens produce acids that
_________________________________________________. As lichens need solid
places to survive: they become victims of their own success. Mosses and herbs are well
suited to living in the shallow soil environment created by the lichen, and they
__________________________________________________________________ .
The mosses and herbs continue to build up the soil. _____________________
______________________________________________________________________
______________________________________________________________________
__________________. Eventually the land becomes suitable for shrubs and then for
trees. The early dominant trees in the community will be species like poplar, which thrive
in bright, sunlit conditions. As more trees grow in the area, however, there is less
sunlight, and maples, which grow in shade, supplant the sun-starved poplars. The
maples eventually dominate the community, because they don’t change the soil
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BCLN BIOLOGY 11 – Rev July 2014
composition and thrive in their own shade. ____________________________________
____________________________________________________________, with maple
as the dominant species. ________________________________________________
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________.
.
A term that you should also be familiar with is ___________________________.
Keystone Species is _____________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
__________________________________________. Keystone species help to support
the ecosystem (entire community of life) of which they are a part. A classic keystone
species is a small predator that prevents a particular herbivorous species from
eliminating dominant plant species. Since the prey numbers are low, the keystone
predator numbers can be even lower and still be effective. Yet without the predators, the
herbivorous prey would explode in numbers, wipe out the dominant plants, and
dramatically alter the character of the ecosystem.
Salmon are keystone species in many BC ecosystems as many other organisms are
dramatically influenced by their presence, absence and health.
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BCLN BIOLOGY 11 – Rev July 2014
3.4 PRACTICE: SUCCESSION
1. Ecosystems in BC frequently experience ecological succession:
a. Please define ecological succession. (1 mark)
b. The Athabasca Glacier in BC is rapidly receding due to recent global
warming trends. Please explain the type of ecological succession that will
be occurring in its wake. You may describe in a paragraph format, step
wise format, or well labelled diagram however, be sure to identify all key
steps and to explain all important terms. (5 marks)
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BCLN BIOLOGY 11 – Rev July 2014
c. Every year BC experiences numerous large forest fires. Please explain the
type of ecological succession that will be occur in the wake of the fires. You
may describe in a paragraph format, step wise format, or well labelled
diagram however, be sure to identify all key steps and to explain all
important terms. (5 marks)
~ END OF BIOLOGY 11 UNIT 3 LEARNING GUIDE ~
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BCLN BIOLOGY 11 – Rev July 2014
UNIT 3 ANSWER KEY
3.1 PRACTICE: INTRODUCTION TO ECOLOGY
1.
Please relate organism to population to community to ecosystem to biosphere. (5 marks)
Organisms refer to the various living things that can be found living within
populations, communities, ecosystems and the biosphere. A population refers to all
the individuals of a single species living within a given area that are able to mate and
reproduce. A community refers to all the interacting populations within an area
whereas an ecosystem refers to the populations and the abiotic factors that
interact within a given area. The biosphere includes all ecosystems and indeed,
anywhere on or in land, water or air that living organisms can be found.
2 - 9. Answers are not provided for fill-in the blank question.
3.2 PRACTICE: ENERGY FLOW IN ECOSYSTEMS
1. Please compare and contrast food chains and food webs. (3 marks)
Food chains and food webs both show feeding relationships and the flow of energy
from one organism to another. However, food chains show very simple, direct
feeding relationships whereas as food webs are expanded to show more complex
feeding relationships within an ecosystem.
2. Please write the chemical equation for:
a. photosynthesis and identify which organelle performs this process. (2 marks)
Solar Energy + H20 + C02  C6H12O6 (carbohydrate) + O2
chloroplast
b. cellular respiration and identify which organelle performs this process. (2 marks)
C6H12O6 (carbohydrate) + O2  Energy (in the form of ATP) + H20 + C02
mitochondria
3. Please compare and contrast photosynthesis and cellular respiration with respect to energy flow,
purpose, and organisms involved. (6 marks)
In photosynthesis, autotrophs such as plants and photosynthetic bacteria, convert
solar energy to carbohydrates for storage and further self-use by the
mitochondria.
In cellular respiration, autotrophic organisms convert the
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BCLN BIOLOGY 11 – Rev July 2014
carbohydrates produced by their chloroplasts into a more user friendly-form of
energy (ATP) that can be used to run cellular processes. In contrast, heterotrophic
organisms cannot produce their own carbohydrate from solar energy and therefore,
must consume them by eating the autotrophs. The heterotrophs' mitochondria then
perform cellular respiration to convert the consumed carbohydrates into ATP to run
their cellular processes.
4. Please explain, with respect to energy flow and the concept of biological pyramids, why there is
always fewer numbers and less biomass at the top of a food pyramid. (3 marks)
Ninety percent of the energy either produced or consumed at any given trophic level
is used to actually sustain the life processes of that level. This means that there is
only approximately ten percent of the energy left over to sustain the next trophic
level up. As there is less energy available, fewer organisms and biomass can exist at
the next level, leading to the characteristic pyramid shape of organism number and
biomass as we move up the trophic levels.
5.
Please explain the difference between bioaccumulation and biomagnification. (3 marks)
Bioaccumulation and biomagnification both refer to the build-up of toxins over time.
However, bioaccumulation refers to the build-up within a single individual over time
whereas biomagnification refers the fact that the levels of such toxins increase
within the organisms such that the higher an organism is on the food chain the
greater the concentration of toxins within the organisms
3.3 PRACTICE PART 1 of 2: PROPERTIES OF POPULATIONS
1. Please define population. (1 mark)
A population is a group of organisms that are of the same species that live in a
particular location together at the same time.
2. Please define population density. (1 mark)
Population density refers to the number of organisms within the same population in a
given area (for example 20 cougars in 2000 km 2 represents a population density of 1
cougar/100 km2). Population density essentially measures how crowded a species is.
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BCLN BIOLOGY 11 – Rev July 2014
3. Please identify and describe the three patterns of population dispersion. (3 marks)
4. Please identify and describe the three patterns of survivorship curves. (3 marks)
5. If a population of 5000 plants is on an isolated island (no immigration or emigration), and 400 new
plants are sprouting in the population for every 200 that are dying:
a. What is the growth rate of the population? (3 marks, 1 each for ESE = Equation, Substitute,
Evaluate)
Equation: r = [(b + i)- (e + d)]/n
Where r represents growth rate, b represents birth rate (= 400 sprouting), i represents
immigration (assume 0 as none mentioned), e represents emigration rate (assume 0 as none
mentioned) and d represents death rate (= 200 deaths) and n represents the total number of
individuals in the original population (= 5000)
Substitution: r = 400-200/5000
Evaluate: r = 0.04
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BCLN BIOLOGY 11 – Rev July 2014
b. How many plants would there be after 3 years at this growth rate? (3 marks, 1 each for
ESE = Equation, Substitute, Evaluate)
While there is an equation to solve this, it is not in the notes so here's how you can
do it long hand
Equation: For each year: population = r(n) + n
Substitute and Evaluate:
After year 1: population
After year 2: population
After year 3: population
= 0.04(5000) + 5000
= 5200
= 0.04(5200) + 5200
= 5408
= 0.04(5408) + 5408
= 524
6. If a population of 10 000 mice are on the island, and 40 swim off the island while 50 swim on, and
5000 mice are born in the population for every 6000 that are dying:
a. What is the growth rate of the population? (3 marks, 1 each for ESE = Equation, Substitute,
Evaluate)
Equation: r = [(b + i)- (e + d)]/n
Where r represents growth rate, b represents birth rate (= 5000), i represents immigration (=
50 e represents emigration rate (= 40) and d represents death rate (= 6000 deaths) and n
represents the total number of individuals in the original population (=10 000)
Substitution: r = [(5000 + 50) – (6000 + 40)]/10 000
Evaluate: r = - 0.099
b. How many mice would there be after a period of 2 years? (3 marks, 1 each for ESE =
Equation, Substitute, Evaluate)
Equation: For each year: population = r(n) + n
Substitute and Evaluate:
After year 1: population
After year 2: population
= -0.099(10 000) + 10 000
= 9100
= -0.099(9100) + 9100
= 8118
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BCLN BIOLOGY 11 – Rev July 2014
3.3 PRACTICE PART 2 of 2: PROPERTIES OF POPULATIONS
1. Scientists model population growth in many ways:
a. Please compare and contrast the exponential growth model and the logistic growth
model. It is ideal to draw the graphs (make sure they are appropriately and completely
labelled) and then to explain what each curve is representing. (6 marks)
Exponential growth models assumes that growth
occurs in an unlimited fashion. The growth rate would
exponentially increase as the population numbers that
are reproducing increase. This is rarely the case as
there is generally limited resources such as limited
food or space.
Logistic growth models account for the limiting
resources. There is an initial exponential growth rate
followed by a more stable growth rate once a
population reaches the limits of its resources.
When/where the growth rate stabilizes is the
carrying capacity which represents the number of
organisms that an environment can support over a
prolonged period of time.
b. What model is the better representation of growth in the vast majority of populations?
Why? (2 marks)
The logistic growth model is generally the better representation of growth
as the vast majority of population face limited resources such as food and
shelter.
2. Population growth can be influenced by density-independent factors and density-dependent
factors.
a. Please give an example of a density-independent factor and how it influences population
growth. (1 mark)
Density-independent factors are any factors that can affect population
growth regardless of size of population such as pH of water or temperature
or a flood.
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BCLN BIOLOGY 11 – Rev July 2014
b. Please give an example of a density-dependent factor and how it influences population
growth. (1 mark)
Density-dependent factors are any factors that can affect population growth
depending on the size of the population such as intra-species competition for
food, water and space.
3. Using pictures/symbols and as few words as possible (this is a critical-thinking challenge) clearly
explain cyclic population fluctuations amongst predators and their associated prey. (3 marks)
Initially…few
= very few
Overtime,

as not enough food
which attracts more
Such that
Which then leads to fewer

as there are fewer
…taking us back to the beginning of the cycle.
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as they get eaten
available to eat…
BCLN BIOLOGY 11 – Rev July 2014
3.4 PRACTICE: SUCCESSION
1. Ecosystems in BC frequently experience ecological succession:
a. Please define ecological succession. (1 mark)
Ecological succession refers to the gradual and sequential change within a community
due to interactions between the various biotic and abiotic factors.
b. The Athabasca Glacier in BC is rapidly receding due to recent global warming trends.
Please explain the type of ecological succession that will be occurring in its wake. You
may describe in a paragraph format, step wise format, or well labelled diagram however, be
sure to identify all key steps and to explain all important terms. (5 marks)
As a retreating glacier leaves nothing but bare rock behind the community would
experience primary succession as follows:
c. Every year BC experiences numerous large forest fires. Please explain the type of
ecological succession that will be occur in the wake of the fires. You may describe in a
paragraph format, step wise format, or well labelled diagram however, be sure to identify all
key steps and to explain all important terms. (5 marks)
As a forest fire leaves soil and some living organisms behind the community would
experience secondary succession as follows:
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