1. UNIT 6 PART 1: ORGANIZATION IN THE BIOSPHERE
The biosphere is the part of earth where living things exist.
It is about 20 km thick from the ocean floor through part of the atmosphere.
Includes land, sea, and air.

2. Ecology
The branch of biology that deals with the interactions among living things and their environment.

3. Biotic Factors
All living things in the environment and their effects on each other
Eats fish Uses grass for nest
Bird
Fish
Man
Trees
Plants
Insects
Eats insects Eaten by bird, man
Eats fish Mows grass
Provide shade Drop leaves
Provide food and oxygen
Eaten by fish

4. Abiotic Factors
Nonliving things in the environment that determine what types of organisms can survive there
AMOUNT OF LIGHT
TYPE OF SOIL
AMOUNT OF WATER
TEMPERATURE

5. Organization of Living Things
Population- all the individuals of one species in an area
Community- all the populations in an area
Ecosystem- the community and the environment: all living (biotic) and nonliving (abiotic) things

6. Biodiversity Variety in a biological community is called biodiversity.
The greater the biodiversity, the more stable the ecosystem.
A rain forest has high biodiversity
A tundra has low biodiversity
Loss of biodiversity may cause the ecosystem to collapse.
Biodiversity

7. Limiting Factors and Adaptations
Some things can limit the growth of a population:
Food
Water
Disease
Light
Competition
Predation
These are called limiting factors.
Because of variations, some individuals will be better adapted to survive and reproduce than others.

8. Carrying Capacity When conditions are good populations increase.
Limiting factors control the size of a population causing growth to slow or reach equilibrium (birth rate = death rate).
The maximum population size that an ecosystem can support (zero growth) is called the carrying capacity.

9. Types of Organisms Heterotrophs (Consumers) eat other organisms.
Herbivores eat plants.
Carnivores eat animals.
Predators
Scavengers
Omnivores eat both.
Decomposers eat remains of dead organisms.
Fungi
Bacteria
Autotrophs (Producers) make their own food by photosynthesis or chemosynthesis.
Green plants and some bacteria

10. Habitat and Niche
Each organism has a particular part of the environment where it lives- its habitat.
Squirrel – tree
Fox – den
Rabbit - hole
An organism’s role in the ecosystem (its ‘job’) is its niche.
This includes how, where, when it feeds, reproduces, what it eats, where it lives.
Habitat is part of niche.
Each species has its own niche.

11. Competition Competition occurs when niches overlap.
Eating the same food
Reproducing at the same time
Interspecific competition occurs between members of different species.
Squirrels and chipmunks both eat pine seeds.
Intraspecific competition occurs between members of the same species.
Choosing mates

12. ENERGY AND NUTRIENTS IN AN ECOSYSTEM
Energy does not cycle through an ecosystem but must be constantly supplied because it gets used by organisms. Much of it is lost as heat.
Energy comes from the sun and is made available to all organisms by the producers.
Other materials, like carbon, nitrogen, oxygen, and water, do cycle between living things and their environment.

13. NUTRIENT CYCLES
Nitrogen
Carbon
Water

14. Food Chain
Within an ecosystem there is a pathway of energy flow that always begins with the producers.
Producers  herbivores  carnivores  30
(primary, 10) (secondary, 20)

15. Food Web
Many interconnected food chains make up a food web.

16. Pyramid of Energy and Biomass
In a food chain the amount of available energy decreases with each higher feeding level.
Only 10% of the energy in one level is passed to the next.
Since the total amount of energy decreases, the biomass at each level must also decrease.

17. Decomposers – organisms of decay
Break down the wastes and remains of dead plants and animals. This changes organic matter into inorganic matter that can be reused by other organisms at all levels.
The final consumers in every food chain:
Fungi
Bacteria
They are nature’s recyclers.

18. Symbiosis is a close relationship between two or more different organisms that live together where at least one benefits from the relationship.
Mutualism
+,+
Parasitism
+,-
Commensalism ,0
Symbiote benefits
Host benefits
Host harmed
Host unaffected
Bees & Flowers
Leach & Fish
Robin & Tree

19. Mutualism Both organisms benefit from the relationship:
Termites and cellulose-digesting microorganisms
Bees and flowers
Lichens are an alga and a fungus
Legumes and nitrogen-fixing bacteria

20. Commensalism One organism benefits and the other is unaffected:
Barnacles on whales
Pilot fish and sharks
Cattle egrets and cattle

21. Parasitism One organism benefits and the other is harmed: Tapeworms
Lampreys
Mistletoe

22. Ecological Succession
Ecosystems appear stable but they do undergo change.
The living things alter the environment so species change over time: the community is replaced.
One community changes to another until a stable climax community is reached. This is ecological succession.
The climax community stays until there is a catastrophe such as flood or fire. Then succession will begin again.
The different biomes are defined by the climax community.

23. Ecological Succession on Land
Primary succession occurs in an area that has no existing life, such as on a bare rock or hardened lava.
Secondary succession occurs in an area that has been partially destroyed like a cleared forest.
The first organisms to inhabit a community are called pioneers, such as bacteria, fungi and lichens.
Pioneers break down the rock and create soil and humus.

24. Ecological Succession on Land
Eventually grasses and small animals move into the area as the soil improves.
When these die, the soil becomes richer and can support a greater variety of organisms.
The grasses are replaced by small shrubs.
Shrubs are replaced by the taller pines.
After many years the pines may be replaced by oaks, beeches or maples. These are the dominant species that characterize a climax community.

25. Ecological Succession on Land

26. Ecological Succession in Water
Small ponds and lakes undergo succession and gradually fill in.
Sediments such as soil and leaves wash into the pond, slowly filling it in from the edges.
Emergent plants such as cattails and grasses grow around the edges as the pond gets shallower.
Shrubs move into the newly formed soil.
Trees replace the shrubs as the pond shrinks.

27. Ecological Succession in Water
Chap 25