Biology 20
Equilibrium in the Biosphere
Ecology
 explain
the one-way flow of energy
through the biosphere and how stored
biological energy in the biosphere is
eventually “lost” as thermal energy
 explain
how biological energy in the
biosphere can be perceived as a
balance between both
photosynthetic and chemosynthetic,
and cellular respiratory activities
Ecology
 Study
of the interactions between organisms
and their physical environment and with each
other.
 includes aspects of both the living (biotic) and
non-living (abiotic) components of the physical
environment.
Biosphere
 Biosphere
the part of the earth that is inhabited by organisms.
3 parts:
1 Lithosphere

 Land
2
Hydrosphere
 water
3
Atmosphere
 The
gasses that surround the Earth.
Living vs. Non-living
 There
are two factors which make up the
biosphere.

Biotic Factors
 Living
components of the biosphere
 plants and animals…

Abiotic Factors
 Non-living
components
of the biosphere
 minerals, water, weather...
Interactions Within the
Biosphere
 Abiotic

When a non-living factor affects a living factor.
 i.e.
 Biotic

vs Biotic
The weather affecting a living organism
vs. Biotic
When a living factor affects another living factor.
 i.e.
 Biotic
Two organisms fighting for the same food.
vs. Abiotic
 Abiotic vs. Abiotic
Levels of Organization
Levels of organization
Cell
Tissue
Organ
System
Organism
Population
Ecosystem
Biome
Biosphere
Community
Levels of Organization
Hierarchical Levels within the Biosphere
Biosphere
World
Ecosystem
Lake or River
Community
Lots of different species of organisms
Population
Lots of same species of fish
Organism
Fish
Important Definitions
 Population:
group of individuals of the
same: species, place & time
 Community: populations of all species in
an area
 Ecosystem: community and its biotic and
abiotic factors

interactions
 Biome:

large scale ecosystems
Can be found around the world  tundra,
grassland
Food Chain


a linear illustration that represents the step
sequence of who eats whom in the biosphere.
used to show:
energy transfers
 cycling of matter through the biosphere


Two types:


Grazer: plant, herbivore, carnivore
Detritus: organic waste

Waste – scavengers – decomposers
Assignment 1.1
 Use
your text book and define the
following Terms
Biodiversity
 Producer
 Consumer
Read pages 8-10 (new text only)
Do Questions 1-7 section 1.1 page 10

Equilibrium
Unbalanced
Autotrophs


“self feeders”
Require energy from sun – photosynthesis



Convert energy from sun into a form of
energy that other living things can use
Provides O2 – required by all living things
Provide basic molecules for life


Carbohydrates, proteins, fats, and nucleic
acids
PRODUCERS!
Heterotrophs




Require a source of chemical energy and
basic organic molecules
NO photosynthesis
Feed on plants OR other heterotrophs
CONSUMERS!
A primary consumer eats a producer
 A secondary consumer eats a primary
consumer
 A tertiary consumer eats a secondary
consumer…

General Terms
 Herbivore

An organism that only eats plants.

Rabbit, squirrel
 Carnivore

An organism that only eats animals.

Wolf, Lion, Tyrannosaurus Rex
 Omnivore

An organism that eats both plants and
animals.

Bear, Human
More General Terms
 Scavenger

An organism that feeds on dead organisms or the
wastes of organisms.
 Vulture,
Seagull,
 Decomposer

An organism that breaks down organic wastes and
the remains of dead organisms into simpler
compounds such as:
 carbon
dioxide
 ammonia
 Water
Species At-Risk
Species At-Risk
Species At-Risk
 Indicator
Species – A species sensitive to
small changes in environmental
conditions
Describe why frogs and other amphibians are
important indicator species:
Frogs
live in two different ecosystems
 Water
as a tadpole
 In forest and grassland as adults
Any hazards in either ecosystem will have an
effect on the frogs.
Also
frogs occupy two different food
chains.
Why Are Frogs Disappearing?

The worldwide disappearance of frogs is
puzzling scientists around the globe.
- Loss of Habitat
•
Frogs need wetlands, ponds, or lakes
with clean water to breed and lay their
eggs.
•
They need a place where they can
catch insects such as forest and fields.
- Air and Water Quality


Frogs can breath through their skin, pollutants can
also pass through their skin.
Acid of water also has an ability to reproduce.
- Climate Change


Climate change can cause important changes in
local ecosystems.
If the climate becomes drier frogs populations will
decline.
4. Ultraviolet Radiation


The thin skin of the frog is susceptible to
ultraviolet radiation.
The amount to UV radiation reaching Earth's
surface is increasing because of damage
to the protective ozone layer surrounding
Earth.
Biology 20
Ecology
Energy and Matter
Exchange
27
General Terms
 Ecosystem

A community of organisms interacting with each other
and with their nonliving surroundings.
 Autotrophs
–Producers
 Heterotrophs - Consumers
Input energy
Biogeochemical
Ecosystems are
OPEN SYSTEMS.
Energy and matter
can flow in and out
of system
Cycles
Energy Lost
Ecosystem
Models
Explain the structure of ecosystem trophic levels, using
models such as food chains and food webs
Food
chains
 Food Chain


step sequence of who eats whom in the biosphere.
used to show:
energy
transfers
 Characteristics:


Energy is transferred from organism to organism
Each time energy is transferred about 90% is lost as
heat or used for life processes
Food Chain
 Note


that:
the arrow points at
the eater
the arrows separate
trophic (eating)
levels
Trophic Levels
 Trophic
level: how far an organism is from
the original energy source

Plants – first trophic level
 Original
 When
energy is from the sun
an organism is ingested by another,
energy is transferred



Plant – mouse – owl
Producer – primary consumer – secondary
consumer (top carnivore)
T1 – T2 – T3
Food Webs
 What
would happen if we relied on deer for our
food?
 In reality, a consumer relies on more than one food
source

If one source is scarce, consumer can eat more of
something else
 Food


web:
a series of interlocking food chains
more accurately represents energy pathways
 who
eats whom… really
Food Web
 ABCD
represent
different trophic
levels.
 Level D
represents the
decomposers
Laws of Thermodynamics
Biosphere
requires a
constant flow of energy
Energy flows one way
through the biosphere
following basic scientific
principles called the laws
of thermodynamics
Laws of Thermodynamics
First Law
Energy can be changed in form,
but not created or destroyed.
(Law of conservation of energy)
Energy input = Energy Output
Second Law
Any energy change results in loss of
energy as heat
Energy input  desired energy +
waste energy
Energy Flow
 About
10% of the energy is transferred
from one trophic level to the next.
 During
any change, some of the energy is lost as
waste energy or heat.
 Applied to an ecosystem, as energy flows through
the community there is energy loss at each trophic
level.
 Much of this loss is in the form of heat which is lost
when food molecules are broken down in the cells.
 There would be less energy loss in the community if
only herbivores fed on the producers
Energy Flow in the
Ecosystem
•explain
quantitatively, energy exchange in ecosystems, using
models such as pyramids of energy , biomass, and numbers
•explain the interrelationship of energy, matter and ecosystem
productivity (biomass production)
Ecological Pyramids
 Ecological
pyramids illustrate the energy loss
through the trophic levels
 Solar radiation transformed in plants



Plants create chemical energy
Plant eaten by consumer
Energy lost at each transformation
 Higher
trophic level = less energy available
 Number of trophic levels limited b/c of loss of
energy
Ecological Pyramids
 In



ecological pyramids,
Base -the producer populations
Next Level - the primary consumers
Higher levels and above -the secondary,
tertiary etc.
Ecological Pyramids
 Three


types:
Numbers: total number of organisms in
each trophic levels
Biomass: mass of dry tissue of organisms at
each trophic level
 shows
how mass decreases as you move up
the food chain

Energy: based on energy produced at
each trophic level
Ecological Pyramids
Pyramid of Numbers
Pyramid of Biomass
Human Interference in the
Ecosystem
Fire
Hunting
and fishing
Monoculture
Pesticide usage and
biological amplification
(magnification)
Fire
 Before
the Europeans settlement, wildfires
swept across the land.



Fire destroys vegetation, returning nutrients
to the soil
Fire usually only destroys vegetation above
ground. Allowing new growth.
Fire prevents the over growth of aspen
parkland into the grassland ecosystem
Fire
 European
settlement Impact upon
grasslands.


Fire control (More Aspen Parkland)
Introduction of many new species of plants
(Mustard, pepperfrass, Russian thistle,
pigweed, and stinkweed)
Hunting and fishing
 New
technology has improved ways of
finding animals. Which has resulted in:


Over hunting and fishing
Reducing the number of animals.
Monocultures
 Monoculture:

growing a single species of plant, excluding
others
 Huge

diversity of species on earth
6 - 15 million
 Ecological
change = species extinction
 Humans = biggest change maker
Monoculture Effects
 Impact?
 Humans
rely on a small variety of species
 Other species being decimated



At what cost?
Loss of diversity
Loss of possible cures
 Rainforests:
needs

soil not suited to human
loses productivity in a few years
Pesticides
 Pesticides




used to kill pests
mosquitoes - malaria
pesticides in food chain accumulate
causes loss of diversity.
Example
 DDT:


dichloro diphenyl trichloroethane
developed as a biological weapon in WWII
1950’s - used as a pesticide for insects
 DDT


also affects human pops
found in breast milk
came from sprayed crops
 animals



that ate crops
Banned in Canada and US in 1970’s
Not banned in other areas - Mexico,
Central America
Continues to be produced as a cheap
pesticide in poorer nations
Biological amplification
 Pesticides
accumulate at the top level of
the pyramid
 toxins accumulate in fatty tissue

not released in wastes
 accumulates
each time you move up
 higher trophic level - higher concentration
Biogeochemical cycles
 explain
and summarize the cycling of
carbon, oxygen, nitrogen, and
phosphorus and relate it to the reuse of all
matter in the biosphere
 explain water’s role in the matter cycles,
using its chemical and physical properties
 explain how the equilibrium between gas
exchanges in photosynthesis and cellular
respiration influences atmospheric
conditions