The Web of Life: Interactions among living organisms Populations Interactions in Communities

Ecology n The study of the interactions of living organisms with one another and their physical environment (soil, water, weather etc.)

Vocabulary Review n Population – a group of organisms of the same species that live in the same area n Community – many populations of species that live together in the same habitat and interact with each other n Ecosystem – a community of organisms and their abiotic environment (soil, water, weather) n Biosphere – the part of Earth where life exists (all of the ecosystems on Earth)

Levels of Biological Organization Organism Population Community Ecosystem Biosphere

Limiting Factors- factor that restricts the number of individuals in a population n Biotic – living factors in the environment n Abiotic- nonliving part of the environment

Carrying capacity- largest number of individuals an environment can support and maintain n Predation- the feeding of one organism on another n Predator and prey both adapt to improve survival

Symbiosis n Mutualism- Both species benefit n Commensalism- One benefits the other is not harmed or helped n Parasitism- benefits the parasite but does harm to the host A relationship in which two or more species live in close association

Coevolution n The evolution of two species that is due to mutual influence, often in a way that makes the relationship more beneficial to both species.

What the difference between habitat and niche? n Habitat- the place where a population lives n Niche- the role the organism plays in it’s habitat (eats, sleeps, reproduces etc.)