Ecology An introduction…

Question Are organisms, including humans, “islands”. Why or why not? Support your answer.

Ecology Defined Ecology is the interaction between biotic and abiotic factors in an environment. So what is a biotic factor anyhow?

Biotic Factors The living factors in an ecosystem Examples: We investigate how these factors influence different species. So what is an abiotic factor?

Abiotic Factors The non-living things in an ecosystem. Draw an ecosystem with 5 biotic factors and 5 abiotic factors.

Levels of Biological Organization in Ecology 1.Biosphere 2.Ecosystem 3.Community 4.Population 5.Organism Which is the largest?

Biosphere The portion of the Earth that supports life. So what does that mean? Where does it start? Where does it end?

Ecosystem Interactions among the populations in a community and the community’s physical surroundings, or abiotic factors. Two general types –Terrestrial –Aquatic

Community A collection of interacting populations. EG: Hawks & Mice

Population A group of organisms of one species that interbreed and live in the same place at the same time.

Organism A living thing When discussing organisms, biologists always discuss their habitats and niche. What are the differences between an organism’s habitat and niche?

Habitat vs. Niche Habitat: Where the organism lives. Niche: An organism’s role or position – job. More specifically it is how it survives, and reproduces. It include all of its interactions with the biotic and abiotic parts of its habitat.

Question Why would it be beneficial for a species to occupy a niche different from those of other species? Reduction of competition.

Symbiosis Relationships between living things. Three types. Do you know what they are?

Types of Symbiosis Mutualism –Both species benefit Commensalism –One species benefits, other is not harmed Parasitism –One species benefits, other is harmed

Nutrition & Energy Flow

Question How do different types of organisms obtain energy? hint: think of plants vs. fungi vs. animals

3 Ways Organisms Obtain Energy 1.Autotrophs –Organism that uses light or chemical energy to make energy-rich compounds 2.Heterotrophs –Can not make its own food –Feeds on other organisms –Herbivore, Carnivore, Scavengers, Omnivores 3.Decomposers –Break down complex compounds of dead and decaying plants

Food Chain Can you give a simple example of a food chain?

Trophic Levels Example Food Chain Grass -> Mouse -> Snake -> Hawk Grass = Producer Mouse = Primary Consumer Snake = Secondary Consumer Hawk = Tertiary Consumer

Trophic Level

Food Web Food webs show all possible feeding relationships as opposed to the more simplistic model of the food chain.

Food Web

Food Chain vs Food Web

Pyramids of Energy  Pyramids of energy show the relative amount of energy available at each trophic level.  Organisms expend much of the energy they acquire on life processes, such as respiration, movement, growth, and reproduction. Most of the remaining energy is released into the environment as heat—a byproduct of these activities.  On average, about 10 percent of the energy available within one trophic level is transferred to the next trophic level.

Pyramids of Biomass & Numbers  The amount of living tissue in trophic level is called its biomass. The amount of biomass a trophic level can support is determined, by the amount of energy available. ? Where is the greatest biomass in the picture below ?  A pyramid of biomass - the relative amount of living organic matter at each trophic level.  A pyramid of numbers - shows the relative number organisms at each trophic level.  In most ecosystems, the shape of the pyramid of numbers is similar to the shape of the pyramid of biomass for the same ecosystem, with the numbers of individuals on each level decreasing from the level below it. ? Can you think of examples where this is not true?

Cycles In Nature Water Cycle –Evaporation, transpiration, condensation, precipitation, run-off, percolation Carbon Cycle –All life on earth is based on carbon –Burning, photosynthesis, respiration, death Nitrogen Cycle –Fixation, Protein, Urination, death, denitrification Phosphorus Cycle –Erosion, Phosphate in Soil, Plants, Herbivores & Carnivores, Waste/Death, dissolved in H2O, sediments, rock, plankton, birds

Carbon Cycle

Carbon Cycle

Water Cycle

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Nitrogen Cycle

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Phosphorus Cycle

Phosphorus Cycle