Ch. 18-22 - Ecology

Organisms and their environment

• What is ecology?

• the study of the interactions that takes place between an organism and their environment

Ecology

• Biosphere:

• Portion of the Earth that supports living things

• Ranges from high in the atmosphere to deep in the ocean

• If the Earth were an apple, that would be the thickness of the peel!

What makes up the biosphere?

• Biotic factors

• All living things that live in an environment

• plants and animals

• Depend directly or indirectly for food, shelter, reproduction, or protection

• Abiotic factors

• All nonliving parts of an organisms environment

• air, temperature, moisture, light, soil

• how do these thing affect the organisms life cycle

Organization

• The living world is organized according to different levels

1.The organism

2.Populations

3.Communities

4.Ecosystems

Organization

1.The organism

• Lowest level of organization

• Deals only with the individual plant or animal and nothing else

Organization

2. Population

• A group of organisms of the same species that interbreed and live in the same area at the same time

• Share resources - determines size and distance they live

• Compete for food, water, mates, and other resources

• Some species have different forms to enable less competition

• tadpoles vs. frogs - totally different food requirements

Organization

3.Community

• Populations that interact with each other in a certain area at a certain time

• Contains many different organisms of different species

• Interdependent - changes in one will affect the others!

Organization

4. Ecosystem

• ALL living populations and nonliving things

• Terrestrial ecosystems - located on land (forest, meadows, rotting logs)

• Aquatic ecosystems - fresh and salt water (ponds, streams, oceans)

• saltwater also called marine ecosystems and make up 70% of the Earths surface!

Vocab

1. Ecology

2. Abiotic factor

3. Biotic factor

4. Community

5. Population

A. The non living parts of the environment

B. A group of 2 or more different species living in the same area

C. The study of organisms and the area in which they live

D. A group of organisms of the same species

E. Animals, plants, and fungi

Organisms in Ecosystems

• Where do you live? That is your habitat

• habitat - place where an organism lives its life

• Can change over time

• What else is in your habitat? Do the other things use the resources that same way you do?

• niche - strategies and adaptations and species uses (how it gets food, where it gets shelter, where it reproduces)

• a habitat contains many niches

Symbiosis• Most species do not battle for

survival. Most survive because of the relationships between other species

• Symbiosis - close, permanent association between organisms of different species

Symbiosis• Three types of symbiosis

1.Mutualism

2.Commensalism

3.Parasitism

Symbiosis1.Mutualism

• Relationship in which both species benefit

• Example - ants and acacia trees

Symbiosis1.Commensalism

• Relationship when one species benefits and the other has no effect

• Example - Spanish moss

Symbiosis3.Parasitism

• Relationship when one member of a species benefits at the expense of the other (called the host)

• If the host dies, the parasite dies

Vocab check

1. Parasitism

2. Mutualism

3. Commensalism

4. Ecosystem

5. Organism

A. All living and nonliving things in an environment

B. One species benefits and one has no effect

C. Both species benefit

D. Anything that is alive

E. One species benefits at the others expense

Nutrition and Energy• ALL energy for ALL life comes from

one place :

Nutrition and Energy• The Produces

• Autotrophs - organism that uses light energy to make energy for life functions

• Examples: grass and trees, algae

Nutrition and Energy• The Consumers

• Heterotrophs - organism that cannot make its own food and feeds on other organisms

• Can feed on autotrophs, heterotrophs, or both

Heterotrophs• Heterotrophs that feed only on plants -

HERBIVORE

• rabbits, grasshoppers, squirrels

• Heterotrophs that eat other heterotrophs - CARNIVORES

• lions, alligator, venus fly trap

• Heterotrophs that do not kill for food but eat other animals that have already died - SCAVENGERS

• vultures

• Heterotrophs that eat animals and plant materials - OMNIVORES

• humans, raccoons, bears

Decomposers• Some organisms are called

decomposers

• decomposer - break down and release nutrients from dead organisms

• fungi and bacteria

Flow of Energy• Energy flows from producers to consumers

• Simplest model of energy flow is called a food chain

• how matter and energy move through an ecosystem

• drawn using arrows to indicate energy transfer from autotroph to heterotroph to decomposers

• Berries Mice Black bear

• energy decreases in each transfer

Flow of Energy• Berries Mice Black bear

Fungi

• each link of the chain represents one trophic level

• a feeding step

• A food chain only represents one possible route of energy

Flow of Energy• A food chain is easy to study, but

does not show the complexity that exists

• To show the relationships that exist between various organisms in the community we use a model called a food web

Ecological pyramids• Another model of energy flow in

an ecosystem

• Bottom are the autotrophs

• Each level up is a trophic level

Cycles in Nature• The matter on Earth has a set amount.

It is not endless, but limited.

• Matter is always recycled, never lost

• Cycles:

• Water cycle

• Carbon cycle

• Nitrogen cycle

• Phosphorous cycle

Cycles in Nature• Water Cycle

• We recycle water all the time

• drink water - breathe out vapor / urinate

Cycles in Nature• Carbon cycle

• Carbon is the molecule of life

• During photosynthesis sunlight and CO2 are converted into carbon molecules (like sugar) for energy

Cycles in Nature• Carbon cycle

Cycles in Nature• Nitrogen cycle

• Nitrogen in the soil is used to make important molecules like proteins for plants

• animals then eat the plants and convert the plant N into animal proteins (nitrogen)

• you eat this and it transfers into human proteins

• your waste (urine) takes the nitrogen out of your body and back to the ground where the cycle renews

Cycles in Nature• Phosphorous cycle

• used for energy in your body

• comes from the soil to plants

• you eat plants and when animals die, the body decomposes back into the soil

Succession: Changes over Time

• SuccessionSuccession

• The orderly, natural changes and species replacements that take place in the communities of an ecosystem

• Occurs in STAGES

• Difficult to observe because it can take decades or centuries for communities to succeed

Primary Succession

• The colonization of barren land by communities of organisms

• Takes place on land where there are no LIVING ORGANISMS

• Example:

• Volcano

Primary Succession

• Pioneer speciesPioneer species

• First species to appear on new, barren land

• Example:

• Lichen – group of small organisms

Primary Succession – the process…

• Pioneer species dies….

• Provides 1st stage of soil….

• New soil develops……

• Small weedy plants develop…

• New organisms move in…

• Area grows in size….

Primary Succession• After some time, primary succession

slows down and becomes stable

• Climax community

• Mature, stable community with little or no change

• Change is dynamic – balances out

• May last for hundreds of years

Primary Succession Stages

Secondary Succession• Sequence of changes that takes place

after an existing community is severely disrupted in some way

• i.e. A natural disaster

• Community of organisms inhabiting an area gradually changes

• Occurs in areas that previously contained LIFE + land still contains soil

Secondary Succession

• May take less time to reach climax community

• Example:

• Yellowstone National Park (1988)

Secondary Succession Stages