1. Ecology EOC Review

2. Biotic vs. Abiotic Factors
Biotic = living (plants, animals, bacteria, fungus, protists)
Abiotic = non-living (temp, water, soil, weather, rocks, sunlight, etc)

3. Ecological Organization
Organism ~ one member of one species
Population ~ all members of one species in a given area
Community ~ all populations in a given area
Ecosystem ~ all members of community plus abiotic factors in the area
Biome ~ group of ecosystems with same climate and organisms

4. The Water Cycle

5. The Carbon Cycle

6. The Nitrogen Cycle

7. Succession
Primary Succession = colonization of NEW land by pioneer species until a climax community is reached.
Lava flow  lichens  mosses  grasses  shrubs  trees
Secondary Succession = existing community is destroyed and a new one begins to form
Occurs more quickly than primary succession because soil is already present and seeds were left behind
Forest  Fire  mosses  grasses  shrubs  trees

8. Ecosystem Relationships
Niche vs. Habitat
If an organism’s habitat is its address, its niche is its occupation.
Competition
Organisms of same or different species try to use same resource at same place during same time.
Competition can be reduced by developing different niches.
Ex. 3 species can easily live in same tree if one eats leaves, one eats bark and another eats the flowers.
Predator-Prey
Organism doing killing = predator
Organism being killed = prey

9. Symbiosis Mutualism – both species benefit from the relationship
Flowers may feed on insects, which may in turn disperse pollen to other flowers
Commensalism – one species benefits and the other is unaffected by the relationship
Barnacles attach to the skin of a whale to catch more food particles
Parasitism – one species benefits and the other is harmed by the relationship
Tapeworms live inside a human intestine and feed from the human

10. Energy Flow Producers (autotrophs) Consumers (heterotrophs)
Use sunlight to make their food and energy through photosynthesis or chemosynthesis
Only plants and some bacteria/algae are autotrophic
Consumers (heterotrophs)
Must acquire their energy from other organisms
Herbivores = eat plants only
Carnivores = eat animals only
Omnivores = eat both plants and animals
Scavengers = eat dead or decaying plants and animals
Decomposers = break down dead or decaying plants or animals

11. Feeding Relationships
Food Chains = series of steps in which organisms transfer energy by eating and being eaten
Arrow shows the direction of energy transfer in the food chain
Ex. Grass  Grasshopper  Mouse  Snake  Hawk

12. Feeding Relationships
Food web = links all food chains together in an ecosystem

13. Trophic Levels
Producers – get energy from sun & use some for own metabolism
Primary Consumers – get 10% of original energy from producers and use some for own metabolism
Secondary Consumers – get 10% of energy from primary consumers and use some for own metabolism
Tertiary Consumers – get 10% of energy from secondary consumers and use some for own metabolism

14. Ecological Pyramids

15. Populations Population Growth
If birth rate is larger than death rate = growing
If birth rate is smaller than death rate = shrinking
Immigration = movement into a population
Emigration = movement out of a population

16. Populations Exponential Growth (J-shaped Curve)
Occurs when individuals reproduce at a constant rate (ex. every individual has 2 kids)
Will occur under ideal conditions with unlimited resources

17. Populations Carrying Capacity (S-shaped Curve)
A population’s growth slows or stops following a period of exponential growth
Carrying capacity = largest number of individuals that a given environment can support

18. Populations Limiting Factors
A factor that causes a population’s growth to decrease
Competition, predation, disease, climate extremes, human disturbance
Density-dependent vs. Density-independent
Density-dependent = limit a population according to population size
Competition, predation
Density-independent = affects all populations the same, regardless of size
Natural disasters

19. Human Environmental Impacts
Human population is growing exponentially with no slowing in sight because of technological advances in medicine.
Humans are clearing habitats of plants and animals to have more room for cities & suburbs as well as space to grow more food for the growing populations.

20. Human Environmental Impacts
Ozone depletion
Ozone protects us from harmful UV radiation from the sun
Chlorofluorocarbons (CFCs) destroy the ozone layer
CFCs are banned, but their affects are lasting as the ozone layer slowly heals itself

21. Human Environmental Impacts
Global Warming
Burning of fossil fuels adds excess carbon dioxide in the atmosphere
Carbon dioxide is an insulator and traps heat in the atmosphere causing the global temperature to slowly rise.
Higher global temperatures could have devastating effects such as melting of glaciers and changes in weather patterns.

22. Human Environmental Impacts
Pesticide Use
DDT and other pesticides are dangerous because they can contaminate groundwater and other water sources.
Biological magnification – concentrations of a harmful substance increase in organisms at higher trophic levels in a food web or a food chain.
Ex. algae pick up toxin from water they live in – plankton eat much algae to survive – small fish eat the plankton – large fish eat the large fish  there is much more DDT in the large fish than the plankton because it has concentrated up the food chain.

23. Practice Questions decreased birth rate and increased death rate
1. Which situation would result in the greatest increase in the human population?
decreased birth rate and increased death rate
increased infant mortality and decreased death rate
decreased death rate and increased birth rate
increased birth rate and increased infant mortality
2. In a forest ecosystem, which is an abiotic factor?
the amount of rainfall
the size of the deer
the type of trees
the number of birds
3. In the carbon cycle, atmospheric carbon dioxide is converted into organic material by which process?
cellular respiration
decomposition
photosynthesis
transpiration
4. Why do ecosystems rarely contain more than a few trophic levels?
Energy transfer efficiency is high.
Energy transfer efficiency is low.
Energy amounts remain constant.
Energy cannot flow through levels.

24. Practice Questions
5. Recent climate data suggests a global warming trend. The most likely cause could be an increase in which gas?
oxygen
carbon dioxide
nitrogen
hydrogen sulfide
6. Silt and nutrients from eroding farmland flow into a lake. As a result, which will most likely increase first?
fish population
shore vegetation
algae growth
dissolved oxygen
A community is studied and several interactions are observed and recorded.
Which type of interaction could illustrate the process of mutualism?
interaction A
interaction B
interaction C
interaction D