Principles of Ecology

Biotic vs. Abiotic Factors What is Ecology? Ecology is the study of interactions between organisms and their environment. Biotic vs. Abiotic Factors Biosphere – portion of the Earth supporting life Biotic factors a. All organisms inhabiting the environment b. Each organism adapts to its part of the biosphere Abiotic factors a. Nonliving parts of the environment b. Can determine which species will survive examples: rainfall, temperature, light, soil

Abiotic Factors Biotic Factors ECOSYSTEM

C. Levels of Biological Organization Populations a. A group of organisms of the same species living together b. Must compete for resources Community a. Several populations that interact b. Changes in one population will cause changes in the others Ecosystem a. Interactions between populations and their surroundings b. 2 main types: 1. Terrestrial – land 2. Aquatic – fresh or salt water

Levels of Biological Organization

D. Niche vs. Habitat Niche Habitat Place where an organism lives The role an organism plays in the environment (Its “job” in the community) Habitat Place where an organism lives Three Species of Warblers and their niches Cape May Warbler Feeds at the tips of branches near the top of the tree Bay-Breasted Warbler Feeds in the middle part of the tree Yellow-Rumped Warbler Feeds in the lower part of the tree and at the bases of the middle branches Spruce tree

E. Types of Feeding Relationships Autotrophs a. Self-feeders, produce their own food b. Example: plants, algae Heterotrophs a. Depend on other organisms for food b. Herbivore – eats only plants c. Carnivore – eats only meat d. Omnivore – eats both

a. Break down and absorb nutrients from dead organisms Decomposers a. Break down and absorb nutrients from dead organisms b. Example: mushrooms, bacteria Commensalism a. Relationship in which one species benefits and the other is not affected b. Example: remoras that live on/around a shark’s mouth bacteria Remora on a Ray

a. One organism benefits and the other is harmed tickbirds Mutualism a. Both species benefit b. Example: tickbirds eat parasites off of a rhino Parasitism a. One organism benefits and the other is harmed b. Example: tapeworm living inside a person’s intestine oxpeckers

F. Compare Food Chains and Food Webs a. Model showing movement of energy through the ecosystem b. Uses arrows to show “what eats what” Grass  Cow  Human Food Web Food Web a. More complicated than a food chain b. Shows more than one food source for each organism c. More realistic view of energy transfer