
Homework:
 PLANTS Test on Tuesday (review Monday after school)
 Chapter 50 & 54 Notes due Wednesday – and BIOME CHOICE
for project

Do Now:
What is the difference between biotic and abiotic?
Define a…
community
population
ecosystem
 Goals for Today:
1.
2.
 Identify the realms of population, community, and ecosystems
ecology
 Describe the difference between r- and K-selected species and
their modes of population growth
1.
Interdependence – Food webs and
population interactions
2.
Energy flows in one direction and is
transferred inefficiently
3.
Nutrients cycle: your waste = my food
4.
Human impacts
“Life history” strategies - based on
reproductive strategies
Two extremes:
The Fast and the Furious/
The Young and the Restless
Slow and Steady
Survivorship Curves
Fraction
of
Survivors
Max. Life Span

Determined by…
 Birth rate
 Death rate
 Immigration
 Emigration

Density-dependent –
 Depends on population density (has a greater
effect on higher-density populations)
 Ex:

Density-independent –
 Does not depend on population density (kills
same proportion regardless)
 Ex: weather conditions, toxic pollutants,
amount of sunlight
Occurs when…

Unlimited food

Low levels of predation

Not a lot of disease
Lack of density-dependent
factors
r-selected populations
dN/dt = rmaxN
N = population size
rmax = natural rate of increase
Carrying Capacity (K) –
the maximum population
size that an environment
can sustainably support
over time
Logistic growth occurs
when…
Density-dependent factors
(food, habitat, etc.) are in
effect
K-selection
dN/dt = rmaxN[(K-N)/K]

What kind of growth is the human population
experiencing?

What is Earth’s carrying capacity for
humans?

Homework:
 Revisions on Free Response section of plant test – required
for anyone who has written comments even if you scored a
10!
 Completed Ecology notes and top 3 Biome choices

Do Now:
Get back your test and look it over…
 Goals for Today:
 Define and explain niche and succession
 Describe relationships in community ecology

Niche –
 The particular way that a species uses biotic and
abiotic resources in its environment
 “Job description” – includes habitat, food & water
sources, etc.

Species interactions can be positive,
negative, or neutral
 Examples…

Occurs when two species have overlapping niches!
 Examples
 Niche partitioning via natural selection

Introduced/Exotic Invasive Species
 Often out-compete native species
 Why?
 Result?

Homework:
 Work on your Biome Project over break. Nothing due right
when we get back so have a well-deserved vacation!

Do Now:

What are some adaptations of prey?
Goals for Today:
 Explain how natural selection drives adaptations in
predators and prey
 Interpret a food web
 Define and explain succession
 Start your Biome project!


One organism eats another
Can drive natural selection in both
predator and prey
 Predator adaptations
 Prey adaptations
▪ Cryptic coloration
▪ Toxins and warning coloration
▪ Mimicry

Predator-prey
population cycles
This picture shows a
mountainside in NH
that was clear-cut
(all trees removed).
How do you think this
area would look in a
year? In 5 years? In
50 years?

The changes in community composition
(number and type of species) over time, after
an ecological disturbance
 Primary Succession – when a new community is
established in a lifeless area (no soil, etc.)
▪ After a glacier, volcanic eruption, new volcanic island
 Secondary Succession - when an existing
community is wiped out, but soil and some life
remains
▪ After forest fire, or land cleared for farmland

Colonization of the disturbed area often
shows a predictable sequence of steps, with
predictable species
 Pioneer species – first ones to colonize
 Climax species – those that are dominant in the
stable, end-stage, fully “recovered” community
Homework:
 Work on Biome Project
Do Now: On an index card…
What is one thing you learned in our ecology unit
before break?
 How is your biome project going? What have you
accomplished so far? Where are you getting stuck?
What are your next steps? Do you need my help or
advice on anything?
 Goal for Today:

 Apply knowledge of population and community ecology to AP
Biology exam questions.
Homework:

Work on Biome Project
Do Now:
 Sit with your partner from yesterday
 We’ll correct your practice quizzes together…
Goal for Today:
 Define and explain trophic levels and primary productivity
 Explain energy transfer through ecosystems, and relate
this to biological magnification
Homework:
 Lab 12 Pre-Lab for Part A (read all background info, answer
questions on pages 1-2)
Do Now:
 Take out your notebooks
 Get ready to answer the question on the next slide
Goal for Today:
 Define and explain trophic levels and primary productivity
 Explain energy transfer through ecosystems, and relate this to
biological magnification
 Explain how water, carbon, and nitrogen cycle through
ecosystems
 Explain the effects of clear-cutting and run-off on forest and
aquatic ecosystems
 Apply all of this to your biome project!
Chemical cycling vs. Energy flow
What’s the difference? What do you notice?
ENERGY FLOW
Energy flow: Open system!
Input: Solar energy
Output: Heat
Energy flows in one direction (producer  consumer …)
Energy is lost as heat during every energy transfer!
The 10% rule – only about 10% of the energy from one
level gets transferred to the next trophic level.
The rest is used for cell respiration and/or lost as heat.
If the seawater is
contaminated with
a chemical toxin,
which organism
will show the
highest levels of
the toxin in its
tissues?
Biological
Magnification
The increase in the
concentration of a
toxin within
organisms’ tissues as
you move up a food
chain
Why does this
happen?
What determines how much energy is captured and
flows through an ecosystem?
Total PP (also known as gross primary
productivity) = the total amount of light
energy that is converted into chemical energy
by photosynthesis in a given amt. of time.
Net PP = Gross PP minus the energy used by
producers for cell respiration
 This is the amount available to the rest of the food
web
NPP = GPP – Respiration




Amount of sunlight
Amount of water
Temperature
Amount of nutrients
NUTRIENT CYCLING
Closed system – no inputs or outputs!
Chemical nutrients cycle between abiotic sources (air, water,
soil) and biotic sources (producers, consumers, decomposers)
Water Cycle
What powers it?
Carbon Cycle
Water is both a reactant and a product in the carbon cycle.
Explain!
In what
form is the
carbon at
this point in
the cycle?



Nitrogen (N)
Phosphorus (P)
Potassium (K)
N
P
Nitrogen Cycle
Who are the key players in cycling nitrogen?
Plug in the hot plate and start heating some water!!
Homework:
 Biome Project due Tuesday – be ready to share it with
the class
Do Now:
 Take out your Lab 12 packet to review the pre-lab
Goals for Today: You will be able to…
 Define DO and explain the factors that influence it
 Follow a procedure for measuring DO in water samples
 Test a hypothesis about the effects of water temperature
on DO concentration