Ecology and our World Ecology The study of interactions between living things and their environment Levels in Ecology 1. Organism A single member of a species 2. Population A group of individuals of a single species that live in the same area at the same time. 3. Community A group of interacting populations. 4. Ecosystem A biological community and all of the abiotic factors that affect it. 5. Biome A large area that is characterized by certain soil, climates, plants, or animals. 6. Biosphere The portion of Earth that supports life.

1. Biotic Factors All living organisms 2. Abiotic Factors The non-living factors in an organisms environment Ex. Temp., soil type, pH, air and water currents, sunlight, rainfall 3. Habitat 4. Niche The natural home or environment of an organism How an organism meets its needs for food, shelter, and reproduction

How do organisms interact? Autotrophs (Producers) - organisms that produce their own energy, and are food for other organisms. Heterotrophs (Consumers) - organisms that have to eat other organisms for their energy

Consumers come in a wide variety Herbivores - Organisms that eat only plant material. Carnivores - Organisms that eat only other animals. Omnivores - Organisms that eat both plant and animal. Detrivores - Organisms that eat “dead matter” Decomposers - Organisms that break down dead organic matter (fungi and bacteria) Scavengers - Organisms that ingest other dead organisms (buzzards and vultures).

5 Trophic Levels Each Level In A Food Chain or Food Web is a Trophic Level. Producers (autotrophs) Producers (autotrophs) – Always The First Trophic Level – How Energy Enters The System

6 Trophic Levels Consumers (herbivore, Omnivore, Carnivore) Consumers (herbivore, Omnivore, Carnivore) – Primary: eats the producers – Secondary: eats primary consumer – Tertiary: eats secondary consumer – Quaternary: eats tertiary consumer

Who eats who? Food Chain - a series of steps showing what each organism eats in an ecosystem. (transfer energy) Producer ( trapped sunlight & stored food) Primary Consumer Secondary Consumer Tertiary consumer Quaternary Consumer

Who eats who? Food Web - a chart linking all food chains in an ecosystem

Another way to show relationships Ecological Pyramids Biomass Pyramid -each level in the pyramid shows the total mass available at each trophic level -Measured in calories or kilocalories and kg/km 2 or g/m 2 Or kg/km 2

Numbers Pyramid - each level shows the number of individuals in each trophic level

Energy Pyramid - each transition shows the amount of energy retained from one level to the next. 10% Rule: Only 10% of the energy from food is actually incorporated into running cell processes! 90% 90% of energy is lost to the atmosphere as heat from one level to the next.

Symbiotic Relationships 1. Mutualism Both individuals benefit. 2. Commensalism One is helped, one is neither helped or harmed. 3. Parasitism One is helped, the other is harmed. Ex: lice, ticks, mosquitoes, mistletoe, tapeworm hornworm caterpillar and the braconid wasp

Biotic factors in the environment interact in many ways Competition When groups are using limited resources Situation leaves winners and losers. Predation When one organism feeds on another Limiting Factor Any factor that restricts the numbers, reproduction, or distribution of an organism Ex. Food, space, water, climate Tolerance Climax Community The ability of an organism to survive when dealing with negative factors. A stable, mature community that results when there is little change in factors. The maximum amount of a species that an environment can support.

-What causes the prey population to increase? -Why is the predator line consistently below the prey line? - Why does the prey population tend to level off around the same number each cycle. Prey- Deer Predator- Coyote

Ecosystems are constantly changing. Succession is the change in an ecosystem that happens when one community replaces another as a result of changing biotic and abiotic factors. -happens in an area that has NO soil and happens very slowly. -The pioneer species will be lichen and mosses. Primary succession:

Secondary succession: Ecosystems are constantly changing. -Happens when an established population is disrupted by things like fire, flood, or windstorm -The pioneer species will be small plants and animals.

Cycles in Nature Biogeochemical Cycles The exchange or movement of matter through the biosphere. These cycles involve: - Living organisms (bio) - Geological processes (geo) - Chemical processes (chemical)

Cycles in Nature Water Cycle - shows the different stages that water goes through in ecology

Carbon, in the form of CO 2, is recycled quickly through living organisms during photosynthesis and cellular respiration. Carbon enters a long- term cycle when it is buried underground and converted to fossil fuels.

Nitrogen Cycle The largest concentration of nitrogen is found in the atmosphere but plants and animals cannot directly use atmospheric nitrogen. Nitrogen fixation is a process of capturing and converting nitrogen into a form that is useable by plants. – Bacteria – Lightning – Fertilizer Denitrification is a process where some soil bacteria convert fixed nitrogen compounds back into nitrogen gas to be released back into the atmosphere.