Ecology

Levels of Organization 1. Organism 2. Population A group of individuals that are the same species, live in the same area and breed with others in the group

Levels of Organization 3. Community 4. Ecosystem Different populations that live together in a defined area All the organisms that live in a particular area together with their nonliving environment

Levels of Organization 5. Biome 6. Biosphere Group of ecosystems that have the same climate and dominant communities Part of the earth in which all life exists

Biosphere Biome Ecosystem Community Population Individual

What Shapes an Ecosystem? Ecosystems are influenced by biological and physical factors Biotic Factors living organisms in a habitat includes birds, bacteria, mushrooms, plants, etc Abiotic Factors Physical or nonliving factors Includes temperature, water, soil, weather

What Shapes an Ecosystem? Habitat The place where a particular species lives Niche The role an organism plays in an ecosystem Includes: How it meets its need for food and shelter How it survives How it reproduces Habitat – “address” Niche – “occupation” or “job”

Habitats & Niches – Tree Stump Earthworm obtains nutrients from organic material it eats Centipede captures and eats beetles

Habitats & Niches – Forest Litter Scavenges dead animals Scavenges dead plants

Community Interactions Competition and predation are two important ways in which organisms interact. Competition occurs when two organisms fight for the same limited resource.

Predation occurs when one organism captures and eats another.

Community Interactions Symbiosis 2 or more species that live together in a close association or relationship Examples include: Mutualism Commensalism Parasitism

Community Interactions Mutualism Relationship in which both organisms benefit

Community Interactions Commensalism Relationship in which one benefits while the other is neither helped nor harmed Human Our eyelashes are home to tiny mites that feast on oil secretions and dead skin. Without harming us, up to 20 mites may be living in one eyelash follicle. Demodicids Eyelash mites find all they need to survive in the tiny follicles of eyelashes. Magnified here 225 times, these creatures measure 0.4 mm in length and can be seen only with a microscope. + Organism benefits Ø Organism is not affected Commensalism

Community Interactions Parasitism Relationship in which one benefits while the other harmed Organism benefits _ Organism is not affected Hornworm caterpillar The host hornworm will eventually die as its organs are consumed by wasp larvae. Braconid wasp Braconid larvae feed on their host and release themselves shortly before reaching the pupae stage of development. Parasitism +

Observing and Inferring From the data, it is clear that the association between the organisms is a. commensalism c. mutualism b. parasitism d. socialism