Transcript Ecology Unit

Ecology
The Flow of Energy: Higher
Trophic Levels
Three hundred trout are needed to
support one man for a year. The
trout, in turn, must consume 90,000
frogs, that must consume 27
million grasshoppers that live off of
1,000 tons of grass.
-- G. Tyler Miller, Jr., American Chemist
(1971)
Ecology
 The study of
interactions
between
organisms and
their environment
Select one thing
in the picture and
remove it. What
would change?
Biosphere
–The portion of
the
environment in
which life can
be sustained.
–Land, Water,
Surface Rocks
and Air
Levels of Organization
• Species
• Population
• Community
• Ecosystem
Species
• A group of
Organisms so
similar to one
another that
they can
breed and
produce
fertile
offspring.
Populations
• A group of
individuals
that belong to
the same
species and
live in the
same area.
• Ex. Herd of
buffalo
Community
a group of
different
populations
that live in
the same
area.
• Ex: all of the
“critters”
living in a
forest
•
Ecosystem
• all living
organisms
in a place
along with
all
nonliving
things
Biomes
- a group of ecosystems that
have the same climate and
similar dominant
communities
Flow of Energy
• Sunlight is the
main source of
energy for all
life on earth.
• Producers
–Make their
own food
from the sun
–Called
Autotrophs
Consumers
• Heterotrophs:
Organisms that rely
on other organisms
for food and energy
– Herbivores: eat plants
– Carnivores: eat other
animals
– Omnivores: eat both
plants and animals
– Scavengers: feed on dead
animal remains
– Decomposers: break
down organic matter
Feeding Relationships
• Food chains
–Show the one way
flow of energy in an
ecosystem
• Food Webs
–Describes all of the
possible feeding
relationships in an
ecosystem
Food Web Activity:
http://www.geographyalltheway.com/ib_geography/ib_ecosystems/ecosyst
ems_energy_flows.html
Compare the types of
feeding relationships
oAutotrophs (producers):
self-feeders; produce own
food; example: plants
oHeterotrophs (consumers):
depend on others for food
oHerbivore: eat only plants
oCarnivore: eat only meat
oOmnivore: eat both plants
and meat
What are you?
oDecomposers: break down
and absorbs nutrients from
dead organisms (Ex: fungi)
oDetritivores: feed on dead
material called detritus
(scavengers)
Tropic Levels
• Each step in the food chain or
food web is called a tropic
level.
• Ecological pyramid
–Shows the energy
movement through the
environment.
–Only 10% is available to
move onto the next level
A food chain and the trophic
levels represented
Grass
Grasshopper
Toad
Snake
Hawk
Bacteria of
Decay
In General Terms:
Autotroph
Herbivore
(Producer)
(Primary
Consumer)
Carnivore
(Secondary, Tertiary, etc
Consumers)
Decomposers
Compare Food chains, food
webs and energy pyramids
o Food Chains: model showing
movement of energy through
ecosystem using arrows to
show “what eats what”
oTrophic levels:
oPrimary consumer: eat plants
oSecondary: eats primary
oTertiary (3rd): eats secondary
Food Web: more
complicated than
chains, shows more
than one food source
for each organism
Energy Pyramid:
shows decreasing
amounts of energy,
biomass, and number of
individuals as you move
up the pyramid
Biotic VS Abiotic factors
 Biotic factors: all organisms inhabiting the
environment, adapted to its particular part of
the world
Abiotic factors: nonliving parts of the
environment, can determine which species
survive
Abiotic
Biotic
Carefully observe the picture
below and list the abiotic factors
and biotic factors you see.
Niche VS Habitat
 Niche:
the unique role an organism
plays in a community, its “job” , unique
to individual
Habitat: place where an organism
lives
Three
Species of
Warblers and
their Niches
Cape May Warbler
Feeds at the tips of branches
near the top of the tree
Bay-Breasted Warbler
Feeds in the middle
part of the tree
Yellow-Rumped Warbler
Feeds in the lower part of the tree and
at the bases of the middle branches
Identify the types of resources
• Natural resources: part
of natural environment,
Ex: soil, water, crops, oil,
gas, wildlife
• Renewable resources:
replaced or recycled by
natural processes
(biodegradable) Ex:
plants and animals
• Nonrenewable resources:
available in limited
amounts, Ex: fossil fuels
Environmental Changes
• Pollution: air, water, noise
• Global Warming: Earth’s
atmosphere heating up due
to trapped gases (fossil
fuels)
– Ex: Arctic, where rising
temperatures and
melting ice are
dramatically changing
the region’s unique
landscapes and wildlife
Factors that Affect
Population Size
 Predation: predators limit number of
prey; pick out old, sick, young
Competition: compete for resources;
water, food, living space, mates
Parasitism/disease
Environmental changes: pollution,
thermal warming, unfit water all affect
population size
May cause species to become
threatened(rapid decline) or
endangered (extinction possible)
Population Growth
 Exponential growth:
occurs when number of
individuals increases
rapidly; produces Jshaped curve on graph
Logistical (linear)
growth: S-shaped curve;
shows steady growth;
slows after populations
reach carrying capacity
Carrying Capacity
Limits the
population size
Affected by
temperature, food
supply, reproduction,
hunting, etc.
Yeast Cells (quantity)
 Carrying capacity:
the number of
individuals that an
environment can
support
Time (hours)
Succession
changes that take place in a
community.
Primary: occurs where no soil
existed; creates new colonies;
pioneer species move in;
continues to grow until limiting
factors become too great
Secondary: disturbance of
some kind changes existing
community; “old” species die
and new species move in;
associated with natural
disasters
Symbiosis: a relationship
between two organisms.
oCommensalism: one
species benefits and the other
is not affected (ramoras that
live on sharks)
oMutualism: both species
benefit (tickbirds eat
parasites off rhinos)
oParasitism: one benefits
and the other is harmed
(heartworms infecting a
dog’s heart)
Limiting Factors and Natural
Selection
oLimiting factor: factor that restricts life, reproduction, or
distribution of organisms; Ex: food, temperature, water, etc.
oNatural selection : survival of the fittest; those species that are
better able to survive in their environment will pass on their genes to
offspring which in turn will be better able to survive
oAfter long periods of time, may lead to changes in organism