Final Exam Review
Unit 3- Ecology

Environment
Every living and nonliving thing that surrounds an organism

Biotic Factors
• Living Factors
• ex: plants, prey, predators, bacteria, fungus
Abiotic Factors
• Nonliving Factors
• ex: water, temperature, sunlight, soil,

Population
A group of one species living in an area

Community
All of the different populations living in an area

Ecosystem
All of the living and nonliving things and how they interact in an area

Biome
Group of ecosystems that have the same climate and community

Habitat
Where an organism lives

Trophic Levels

Autotrophs
Organisms that produce their own food for energy, photosynthesis
Ex: Producers: make their own food, through the process of photosynthesis, ex: plants, algae

Heterotrophs
Organisms that cannot produce their own food for energy
Consumers: Organisms that eat/consume other organisms
• Herbivore
• Carnivore
• Omnivore
• Scavenger
• Decomposer

Herbivore eats plants, primary consumers, ex: deer, cow

Carnivore eats meat/other consumers, ex: lion, tiger

Omnivore eats both plants and animals, ex: humans, raccoons, bears

Scavenger eats dead animals, ex: vultures

Decomposer breaks down dead matter and recycles the nutrients back to the soil, ex: fungus, bacteria

Food Chain shows the flow of energy in an ecosystem, simple

Food Web
• many food chains interconnected
• complex

Ecological Pyramids
• Energy
• Biomass
• Numbers
• decreases as you move up the pyramid,
• producers are always the largest and on the bottom.

Biological Magnification
• The concentration of a toxin increases as is moves through the food chain, highest concentrations at the top of the food chain, ex:
• DDT in bald eagles

Biodiversity
The number of different species in an area, more biodiversity=more stable

Niche an organisms role/job in its environment, two species cannot occupy the same niche

Competitive Exclusion
When two organisms try to occupy the same niche, they will compete. One will stay in that niche and the other will either die or have to occupy a different niche

Fundamental Niche
The niche a species can ideally have, can be larger than the realized niche
Realized Niche
The niche a species actually occupies, can be smaller than the fundamental niche

Niche Diversity the number of different niches in an ecosystem due to abiotic factors
• fluctuating abiotic factors many niches (desert)
• constant abiotic factors=few niches (marsh)

Evolution a slow gradual change in a species over time

Adaptation
A trait that an organism has that allows it to survive in a changing environment

Specialized species
• A species with a small niche, only one food source.
• Ex: koala bear and panda bear
Generalized species
• A species with a large niche, many food sources.
• Ex: mice, roaches

Convergent evolution two species evolve separately to have similar traits because they have similar niches.

Coevolution
• When two species evolve to rely on each other for survival, mutualism
• ex: acacia tree and stinging ants

Predator-Prey predator- the hunter prey-the hunted

Parasitism one organisms feeds off of another organism for survival, one species benefits, the other is harmed.
Ex: tapeworm, malaria, ringworm
– Host: The organism the parasite is feeding off of

Mutualism
• two species rely on each other for survival, both benefit
• ex: Egyptian Plover and Nile Croccodile

Commensalism
One species benefits, the other isn’t harmed or helped, ex: barnacles on a whale

Invasive Species
A non-native species that causes harm to the environment
• Why are they dangerous?
– They outcompete with native species for essential resources
• How do they get here?
– Accidental (in wood), boats (mass transportation), intentional release (pets that get too big), tropical plants for garden

Endangered Species
A species that is close to extinction
Main reason for species endangerment?
• Habitat destruction