1. Ecology
The branch of Biology dealing with interactions among organisms and between organisms and their environment.

2. Biotic vs. Abiotic Factors
All the living factors in an ecosystem
Examples: Plants, Animals, Fungi, Bacteria
All the non-living factors in an ecosystem
Examples: Light, Water, Temperature, Soil, Air

3. Levels of Organization
Organism – an individual of a species (cow)
Population - a group of organisms that can interbreed and live in the same space at the same time (a herd of cows)
Community – the many populations within an ecosystem (cows, grass, flies, etc)
Ecosystems – the living things in the community plus the nonliving things (cows, grass, rocks, streams)
Terrestrial – land ecosystems
Aquatic – water ecosystems
Marine – salt-water ecosystems
Biosphere – the combined portions of earth in which all living things exist

4. Where Organisms Live Habitat – the place where an organism lives
Niche – the role an organism plays in its habitat
Biodiversity – the variety of living things in a given area (highest near the equator)
Ecosystem diversity – the variety of habitats, communities, and ecological processes
Species diversity – the number of different species in the biosphere
Genetic diversity – to total number of the different forms of genetic information found in all living things.

5. Biomes
Tundra
Grasslands
Tundra, taiga, temperate forests, grasslands, desert, tropical rain forests
Each biome is characterized by its unique climate (temperature & precipitation)
The climate determines what plants and animals can survive there.
Taiga
Desert
Temperate Forest
Tropical Rain Forest

6. Ecological Succession – series of predictable changes that occur in a community over time
Primary Succession – occurs in a community where life did not previously exist (lava flow, glacier melts)
Begins with bare rock
Pioneer species – the first organism that moves into the community (usually lichens and mosses)
Once soil is established, grasses, shrubs and trees move in
Lichen
Mosses and small plants growing in cracks on Mount Ranier

8. Ecological Succession – series of predictable changes that occur in a community over time
Secondary Succession – occurs when the dominant plant life of a community is removed (hurricane, tornado, clear-cutting)
Climax Community – the final stable community

9. Flow of Matter & Energy through an Ecosystem
Autotrophs (producers) – organisms that make their own food (example: Plants)
Heterotrophs (consumers) – organisms that rely on other organisms for food and energy (example: Animals)
Herbivore – organisms that feed only on plants
Carnivores – organisms that feed on other animals
Omnivores – organisms that feed on both plants and animals
Detrivores – animal that feeds on dead organic material, especially plant detritus.
Decomposers – organisms that feed on (break down) dead & decaying matter (example: Fungi like mushrooms)
The sun is the ultimate source of energy in our ecosystem

10. Food Chains
Food chains show the movement of energy through an ecosystem
Example: Grass  mice  hawk
Trophic Levels – the position in the food chain
Autotrophs (producers) – use sun’s energy to make food
1st order heterotrophs (consumers) – herbivores (organisms that feed on plants)
2nd and 3rd order heterotrophs (consumers)
Food Webs – show the interconnected feeding relationships in an ecosystem.

11. Food Web

12. Energy Pyramids
Energy pyramids – show the amount of energy available at each level of the food chain
Each step in the transfer of energy is called a trophic level
Rule of 10 –
Energy decreases at each trophic level because organisms only capture 10% of available energy
Other 90% is lost as heat and waste (If you eat, you must excrete)

13. Matter is cycled in nature
Carbon, Nitrogen, Water, and Phosphorus
Matter cycles between the biotic and abiotic parts of the environment
Example: You drink water and water becomes part of the biotic environment. You urinate water and waste, and water becomes part of the abiotic environment

18. Populations
Population Size – the number of organisms living together in the same area at the same time
Population Density – the number of organisms in a given area (example: number of cows per square meter)
Population Growth – the change in the size of the population

19. Types of Population Growth
Exponential Growth – under ideal conditions, the population will increase indefinitely (J-shaped curve)
Logistic Growth – when resources become limited, the population growth slows down and stabilizes (S-shaped curve)
Carrying capacity – the maximum number of individuals an environment can support.
Below the carrying capacity: more births than deaths
Above the carrying capacity: more deaths than births

20. Limiting Factors
Limiting factors – environmental conditions (biotic & abiotic) that effect an organism’s ability to survive
Tolerance – the amount of change an organism can withstand as environmental factors change
Density-dependent limiting factors – limiting factors that are affected by the size of the population (examples: competition, predation, disease)
Density-independent limiting factors – limiting factors that are unaffected by the size of the population (examples: weather, fires, drought, human activity)
Demography – the study of human population growth & decline

21. Communities
Symbiosis – a close permanent relationship between organisms of different species
Mutualism – both species benefit (ex. Lichen- fungi & algae)
Commensalism – one species benefits, other is indifferent (ex. Algae growing on a turtle)
Parasitism – one species benefits, other is harmed (ex. Fleas on a dog)

22. Predation – the act of one organism (predator) killing another organism (prey) for food
Herbivory – herbivores eat plants, but do not often kill them

23. Human Activities
Renewable resource – resources that can be replaced (trees, soil, water)
Nonrenewable resource – resources that cannot be replaced (metals, fossil fuels)

24. Extinction – the complete disappearance of a species
Threatened species – species that are declining rapidly
Endangered species – species that are almost extinct
Extinct species – species that are no longer alive on the planet (ex. Dodo bird)
Introduced/Exotic Species – species that are not native to an area & spread rapidly due to a lack of predators and competition (ex. Kudzu, fire ants)

25. Pollution (habitat degradation) – the contamination of soil, water, air
Acid rain is created when sulfur and nitrogen compounds in smog combine with water in the air.
Greatest threat to biodiversity is HABITAT LOSS

26. Greenhouse effect – trapping of heat in the atmosphere
Ozone layer – layer of ozone (03) that protects the earth from harmful UV radiation
3 R’s of Conservation – Reduce, Reuse, Recycle

27. Greenhouse Effect

28. Plant Adaptations for Response to Environment
phototropism
gravitropism
Tropisms – response to the environment
Phototropism – response to light
Geotropism/Gravitropism – response to gravity
Thigmotropism – response to touch
Positive tropism – response in direction of stimulus
Negative tropism - response away from stimulus
thigmotropism
thigmotropism

29. Hormones
Auxins – stimulate the elongation of cells, which causes plants to grow toward sunlight
Gibberellins – growth hormones, promotes seed germination, stem elongation, flowers, and produces larger fruit

30. Animal Adaptations
Behavioral Adaptations – actions that organisms take to ensure survival (ex. territoriality, migration, making noises, mating behaviors)
Structural Adaptations – Physical characteristics that help organisms survive (ex. woodpecker’s beak, anteater’s snout, camouflage)
Physiological Adaptations – chemical characteristics (ex. spider’s web, snake’s venom, skunk’s spray, antibiotic resistant bacteria)