Download Ecology PowerPoint Lecture Notes

Principles of
Ecology
• Ecology - Scientific study of interactions
between organisms
and their environments.
• Living organisms are connected to other
organisms and non-living things.
• Biosphere- The
zone on Earth in
which life is found.
• Includes air, land,
and both fresh
water & salt
water.
An environment is all the living &
nonliving factors that affect
organisms.
• Biotic factors are
all the living
organisms in an
environment.
• Abiotic factors are
the nonliving parts
of an environment.
Levels of Organization of Living
Things
Biosphere
example: the earth
Ecosystem
example: terrestrial
forests
desert
Ecosystem
example: fresh water
ponds
lakes
Ecosystem
example: salt water
oceans
Community
example: deer, rabbits, birds
Community
example: frogs, dragonflies, minnows
Community
example: sharks, seals, jellyfish
Population
example: deer
Population
example: frogs
Population
example: sharks
Organism
example: a male deer
Organism
example: a female grassfrog
Organism
example: a male tiger shark
• A group of organisms of one species that
interbreed and live in the same place at the
same time.
• Ex. All of the catfish in Saguaro Lake.
• Members of the same population compete for
food, water, mates, & other resources (sunlight,
shelter, etc.)
• All populations depend on other
populations either directly or indirectly.
• Community - A group of interacting
populations.
• Ex. All of the deer, rabbits & squirrels in
the Tonto National Forest.
Ecosystem - Interactions between
populations and the abiotic factors in
their environment.
Examples: Tree, birds, water, and sunlight
Fish, turtles, oxygen, and sunlight
Niche - Role a species plays in
its community.
• Examples:
– What does it eat?
– How much does it
eat?
– What eats it?
– Where does it live?
– How does it use its
environment?
Habitat - The place an
organism lives.
Feeding Relationships
• Autotrophs - Organisms that can make their
own food. Also known as producers.
– Ex: Green plants, some protists.
Feeding Relationships
• Heterotrophs - Organisms that depend
on other organisms for food. Also known
as consumers.
– Ex: Lions, humans, insects, fungi.
Five Types of Heterotrophs
• Herbivores - Feed only on plants. (rabbits)
• Carnivores - Feed only on animals. (lions)
• Scavengers - Feed only on dead
animals. (vultures)
• Omnivores - Feed on both plants and
animals. (bears)
• Decomposers - Break down dead plant
& animal material &
absorbs them. (fungi)
Symbiosis - “Living together”
• A close &
permanent
relationship
between
organisms of
different species.
Symbiosis
• 1) Commensalism
– One species
benefits, the other is
unaffected.
– Ex. Remora and
shark, barnacles
and whales
Symbiosis
• 2) Mutualism
– Both species
benefit from a
relationship.
– Ex. Tick eating
birds and
hippos.
Symbiosis
• 3) Parasitism
– One species
benefits and the
other is harmed
but not killed by
a relationship.
Food chains show how matter &
energy move through an ecosystem.
Examples:
#1: grass---> grasshopper---> frog--->bird
#2: algae---> snail---> raccoon---> coyote
Limitations of Trophic Levels:
a. The low rate of energy transfer between trophic levels explains
why ecosystems rarely contain more than a few trophic levels.
b. Only about 10% of the energy available at 1 trophic level is
transferred to the next trophic level.
Each organism in a food chain
represents a feeding step, or
trophic level:
Alligator
Fourth Trophic Level
Third-order consumer
Turtle
Third Trophic Level
Second-order consumer
Frog
Third Trophic Level
Second-order consumer
Heron
Third Trophic Level
Second-order consumer
Minnow
Second Trophic Level
First-order consumer
Grasshopper
Second Trophic Level
First-order consumer
Snail
Second Trophic Level
Pond Weed
First Trophic Level
Producer
Sawgrass
First Trophic Level
Producer
Algae
First Trophic Level
Producer
Food web - A series of interconnected food chains that
demonstrates all of the possible
feeding relationships within a
community.
Answers to Review Questions:
1. Producers convert energy from the sun or from organic molecules.
Consumers obtain energy by eating other organisms.
2. Herbivores, carnivores, omnivores, detritivores, and decomposers.
3. They decay, releasing nutrients in organisms, and returning the
nutrients to the ecosystem.
4. Food chains show a single path of energy flow. Food webs show
several paths of energy flow.
5. Many organisms avoid being eaten and the energy is partly lost,
some of the molecules in a body are indigestible, and organisms
use energy for their own life processes. Some are not eaten and
wasted.
Ecological Pyramids
• 1) Pyramid of numbers
- Shows the number of organisms available to the
next trophic level
• 2) Pyramid of energy
- Shows that 10% of energy is available to next
trophic level
• 3) Pyramid of biomass
- Shows the weight of living material at each
trophic level
Ecological Pyramids
Biogeochemical cycles
• Exchange of materials between biotic and
abiotic parts of ecosystems.
• 1) Water cycle
• 2) Carbon cycle
• 3) Nitrogen cycle
• 4) Phosphorus cycle
https://www.youtube.com/watch?v=al-do-HGuIk
The Carbon Cycle
https://www.youtube.com/watch?v=mldBE9Ee3zY
The Nitrogen Cycle
https://www.youtube.com/watch?v=DP24BceOwt8