Transcript Ecology

Ecology is the study of
interactions among organisms
and their environment.
Ecologists are scientists who study
these relationships. Ecologists divide
the environmental factors that
influence organisms into two groups
(abiotic and biotic factors).
Many times, ecologists must
travel to specific
environments to examine
the organisms that live
there.
Food Chain, Webs,
and Pyramid
ENERGY FLOW AMONG ORGANISMS
Everything
you do requires
energy. How do you get the
energy that you need?
All
living things get energy
from their food to carry out
life processes.
Plants make their food.
Animals eat their food.
A
food chain shows how each living thing
gets its food. Plants make food using
energy from the sun. Some animals eat
plants and some animals eat other
animals. Each link in a chain is food for
the next link. Arrows indicate the
direction of energy flow.
A food chain is the passing of food energy from one organism
to another.
Plants are called producers
because they are able to use the
energy from the sun to produce
the food they need using carbon
dioxide and water.
Animals cannot make their
own food so they must eat
plants and/or other
animals. They are called
consumers.
There are three groups of
consumers.
A herbivore is called a primary, or
first order consumer because it eats
the producers.
A carnivore that eats herbivores is a
secondary, or second order
consumer.
Some predators are called tertiary, or
third order consumers. These
animals usually have no predators.
Some animals eat dead animals
or carrion. They are called
scavengers. They help break
down or reduce organic
material into smaller pieces.
hyeina
vulture
roach
DECOMPOSERS
Organisms (bacteria and fungi) which feed on
decaying matter.
 Decomposers
and scavengers break down
dead plants and animals. They also break
down the waste (feces) of other organisms.
Decomposers are very important for any
ecosystem. If they weren't in the ecosystem,
the plants would not get essential nutrients,
and dead matter and waste would pile up.
FOOD WEBS
Most organisms are part of more than
one food chain. Many animals eat more
than one kind of food in order to meet
their food and energy requirements.
These interconnected food chains form a
food web.
All energy comes from the sun - which makes it the
MARINE FOOD WEB
http://www.gould.edu.au/foodwebs/kids_web.htm
ENERGY PYRAMID
Because a large amount of
energy is lost at each link, the
further along the food chain you
go, the less energy is available.
We use the energy pyramid as a
model to show decreasing
available energy at each level in
the pyramid.
0.1%
energy
1%
energy
10%
energy
100%
energy
Why are there more primary
consumers than secondary?
 In
a food chain, energy is passed from one link
to the next.
 Organisms
along a food chain pass on much
less energy in the form of biomass (total
amount of matter used as energy) than they
receive.
A living thing that
makes food using
materials from the
environment (nutrients)
& the
Sun.
Primary - uses food produced
by plants (eats plants)
Secondary - obtains energy by
eating primary consumer
(eats meat)
Living things that eat
the remains and
waste of plants and
animals. Like bacteria,
It breaks down organic
material.
 Producers
are
plants:
 Grass
 Trees
 Flowers
 Weeds
 The produce
energy through
photosynthesis
 Consumers
are
animals (including
humans):
 Bacteria (also
decomposer)
 insects
 rodents
 dog/wolf/fox
 bears
INTERACTIONS AMONG ORGANISMS
Predator-prey
An animal that hunts or kills other animals for
food is called a predator.
An animal that is eaten by another is called
prey.
Can you match some predatorprey relationships?
Predator
Prey
Symbiosis

Symbiosis is a long term relationship between 2 or
more species
- Mutualism – both organisms benefit
ex. Coral (home) and algae (food)
- Commensalism – One organism is helped, while the
other is neither helped or harmed
ex. Remoras ride on sharks and eat what they
leave behind in food scraps
- Parasitism – one benefits (parasite) the other is
harmed (host) and weakened
ex. ticks
A living thing
All organisms of the
same species that
live in the same place.
Population that
shares an area
All populations within a
certain area.
Biome - a large geographical area having the same climate and major life forms.
A ecosystem is a group of organisms & their physical environment.
In an ecosystem you have three classes of consumers:
Herbivore - eats plants only
Carnivore - eats meat
Omnivore - eats both
A habitat is where an organism lives within an ecosystem.
An ecosystem is the
biotic community and its
abiotic factors.
Examples of ecosystems
include coral reefs,
forests, and ponds.
 The
total number of species and biological
communities in a region and the amount of
genetic variation in each species
 The loss of biodiversity is a huge ecological
problem
 Genetic diversity decreases as its populations
decline- consequences in a population to
adapt to changing environment
 Genetic variability-measure of its potential
to adapt; evolutionary insurance policy
The carrying capacity is the
maximum population size
that can live in an
environment over time.
A limiting factor is a biotic or abiotic
factor that restricts the size of a
population.
•Food can be a limiting factor if the
amount of food can only support a
certain number of an animal in a
population.
 Biotic
factors are the living or
once-living parts of the
environment (plants, animalsprey, etc)
 Abiotic factors are the
nonliving parts of the
environment (light, water, air,
nutrients, soil, minerals,
nesting sites)
 The
interaction between two or more
organisms, or groups of organisms, that
compete for the same resources (in short
supply)
 Can be between members of the same
species and/or members of the different
species
 Most important aspects of natural selection
 Results:


reduction in the numbers of one or both
competitorsDistribution of organisms in habitats
•
•
•
•
•
Limit pollution (air, soil, water)
Control transport of invasive species
Limit the use of natural resources (clear cutting
rainforests, interfering with river flow to
wetlands, slow down oil and gas consumption)
Conserve natural resources
Protect endangered species (plants and animals)
Ecological Succession
- the orderly changes in a ecosystem as one type of
community changes into another

Pioneer species – lichens and mosses – live in area and
grow on rocks, releasing acids that break them down
over time to form soil

Plants start to grow in soil

Small animals move into area

Large animals feed on smaller animals

Organisms die leaving richer soil supported larger plants
– shrubs

Soil becomes richer supporting trees

Reaches a stable point of established growth know as a
climax community