Transcript Energy Flow

Biology
Ecology
Energy flow
Matter Cycling
Populations
Ecology
Topics
•
•
Essential Questions
5.
Explain the ways in which energy flows through
an ecosystem.
6.
What role does the carbon cycle play in
photosynthesis and cellular respiration?
7.
How are communities influenced? What are the
major limiting factors that influence carrying
capacity?
8.
What do population growth graphs look like?
Can you identify them?
Ecosystem
energy flow
Cycles in an
ecosystem
•
Limiting Factors
•
Population
Growth Graphs
The Sun
Energy Flow
Sunlight is the main energy source
for life on Earth. Some types of
organisms rely on the energy
stored in inorganic chemical
compounds. Plants use the energy
from sunlight to carry out the
process of photosynthesis.
Other autotrophs, such as sulfur
bacteria, use the energy stored in
chemical bonds for
chemosynthesis. In both cases,
energy-rich carbohydrates are
produced.
Energy Flow
Autotrophs / Producer – An organism that can capture energy form
sunlight or chemicals and use it to produces its own food.
Photosynthesis
The process by which producer take carbon dioxide and water and
convert it into sugar and oxygen.
(Carbon dioxide + Water
chloroplast
Sugar + Oxygen) take place in the
Heterotrophs / Consumer – Organisms that rely on other organisms
for their energy and food supply
Cellular Respiration
The process that releases energy by breaking down glucose and
other food molecules in the presence of oxygen.
(Sugar + Oxygen
mitochondria
Carbon Dioxide and Water) takes place in the
Photosynthesis: CO2 + H2O
Carbon
dioxide
water
CO2 + H2O
Photosynthesis
Light
C6H12O6 + O2
Glucose
sugar
oxygen
C6H12O6 + O2 Cellular Respiration
Producer
(Autotrophs)
Energy Flow: Food Chains
Primary Consumer
(Heterotrophic)
example
Secondary
Consumer (Heterotrophic)
Tertiary
Consumer (Heterotrophic)
Top level
Consumer (Heterotrophic)
Energy Flow
Energy flow in a food
web/chain decreases at
each succeeding
organism in a chain or
web.
The dry weight of all
organic matter within the
organisms of a food
chain/web is called
biomass.
Trophic levels are feeding levels for organisms within an ecosystem,
(1) Producers belong to the first trophic level.
(2) Primary consumers belong to the second trophic level.
(3) Secondary consumers belong to the
(4) Third trophic level.Detritivores and decomposers process detritus
from all trophic levels.
Eating at a lower Trophic
level
Energy Flow: Ecological Pyramids
Energy flow - Extinction
Energy Flow: Ecological Pyramids
Ecological pyramids show
the decreasing amounts of
energy, living tissue, or
number of organisms at
successive feeding levels.
The pyramid is divided into
sections that represent
each trophic level. The area
of each level symbolizes
the amount of energy or
matter remaining at that
level. Because each trophic
level harvests only about
one tenth of the energy
from the level below, it can
support only about one
tenth the amount of living
tissue.
Energy Flow:
Food Webs
What does the Marsh
Hawk feed on?
What would happen if a
chemical was
introduced that limited
the growth of Marsh
Grass?
Tropic Levels
Ecological efficiency is the
term that describes the
percentage of usable energy
transferred as biomass from
one trophic level to another
and ranges from 2%-40%
with 10% being typical.
The greater number of
trophic levels in a food chain,
the greater loss of usable
energy.
The Flow of Energy And the Cycling of
Matter
Cycling of Matter
Biogeochemical
Cycles
The Flow of Energy And
the Cycling of Matter
Carbon Cycle
Keeping up with Carbon
Nitrogen Cycle
The Study of Population Dynamics
Populations change in
size
density
dispersion
age structure
Population density —the
number of individuals
of a population that
inhabit a certain unit of
land or water area.
Population dispersion —
refers to how
individuals of a
population are spaced
within a region.
Age structure of a population is
usually described as the
pre-reproductive stage, the
reproductive stage and the postreproductive stage.
A population with a large reproductive
stage is likely to increase, while a
population with a large post-reproductive
stage is likely to decrease.
Ecosystem Factors
Ecosystem characteristics include a range of tolerance to physical and
chemical environments by the ecosystem's populations Law of tolerance:
The distribution of a species in an ecosystem is determined by the levels
of one or more physical or chemical factors being within the range
tolerated by that species.
Mini Lab: Range of tolerance
Ecosystem Factors
The Sugar Maple
The limiting factor
principle states that
too much or too little
of any abiotic factor
can limit or prevent
growth of a
population, even if all
other factors are at or
near the optimum
range of tolerance.
An abiotic factor such
as lack of water or
poor soil can be
understood here
Populations
limiting
Factors
No population
can grow
indefinitely
due to limited
resources
such as light,
water, and
nutrients and
also due to
competitors
and/or
predators.
Biotic Potential vs.
Environmental Resistance
The biotic potential max (rmax) is the
population's capacity for growth. The
intrinsic rate of increase (r) is the rate of
population growth with unlimited resources.
environmental resistance
consists of factors that limit population
growth.
limiting Factors
No population can
grow indefinitely due
to limited resources
such as light, water,
and nutrients and
also due to
competitors and/or
predators.
Density-independent
population controls affect a
population's size regardless of
its density. These are abiotic
factors in the community.
Density-dependent factors or
population controls have a
greater affect on the
population as its density
increases. Infectious disease is
an example of densitydependent population control.
Limiting Factors Examples:
Extrinsic
Biotic – Density Dependent
Abiotic – Density Independent
Intrinsic
Social Hierarchy
Gender changing
Biotic Potential v. Environmental Resistance
(Logistic Population Growth)
Environmental
resistance
Population size (N)
Carrying capacity (K)
Carrying capacity (K)
is determined by biotic
potential and
environmental resistance.
(K) is is the number of a
species individuals that
can be sustained
indefinitely in a specific
space.
Biotic
potential
Exponential
growth
As a population reaches
its
carrying capacity, its
growth rate will decrease
because resources
become more scarce.
Time (t)
Exponential Growth
Lessons of Kaibab
The Role of Predation in Controlling Population Size
Interactions between predators and their prey change in cycles and
appear to be caused by species interactions, but other factors may
be involved.
Example: Yellowstone Wolves
Age structure
Age structure of a population is usually
described as the pre-reproductive stage, the
reproductive stage and the post-reproductive
stage.
A population with a large reproductive stage
is likely to increase, while a population with a
large post-reproductive stage is likely to
decrease.