Intro to Ecology Abiotic/Biotic Factors, Human Impact, Cycles, Symbiosis, Succession

Biotic- living Abiotic- nonliving Ecosystem- a community of organisms and their nonliving environment

Factors that may affect an ecosystem: Temperature Light pH Water Oxygen Carbon dioxide Radiation Toxins Space Soil Disease Natural disasters Pollution Population increase Urbanization Destruction of habitat Predation Competition Air food

Biotic factor- an living organism and its actions, or the organic matter produced by an organism Abiotic factor- a physical, nonliving part of the environment

Human Impact Acid rain Greenhouse effect Global warming Depletion of food Destruction of habitats Disease Natural disasters Pollution Population increase urbanization

Biogeochemical Cycles Energy and nutrients (chemical compounds that living things need) are transferred through ecosystems. –This occurs through a series of cycles: WATER CARBON NITROGEN ENERGY IS NOT RECYCLED.

Water Cycle 1. Precipitation - water vapor in the air falls to the earth as rain or snow 2. Run-Off - some water runs off the ground into rivers, ponds, lakes, oceans - Water from rain may soak into the soil 3. Percolation - plants take up some soil water. Animals may drink some as well. The rest flows into underground lakes and rivers. 4. Transpiration - extra water exits plants through their leaves or is excreted as animal waste. 5. Evaporation – the water excreted by plants and animals and some water in lakes, rivers, and oceans changes from a liquid to a vapor (gas) as it heats up, entering the air. - This is what clouds are made of! (Condensation)

The Carbon Cycle

During Photosynthesis - Oxygen is given off by producers (plants) in an ecosystem. During Cellular Respiration - Oxygen is used, releasing carbon dioxide (CO 2 ). Death and Decay - When organisms die, SOME carbon remains underground and is converted into fossil fuels (oil). Combustion - Fossil fuels power engines that convert the fuel back into carbon dioxide and release it into the atmosphere. Carbon dioxide (released from cellular respiration and fossil fuels) is then used by producers to make food and release oxygen (photosynthesis).

Nitrogen Cycle Plants and animals need nitrogen to make protein. Air has lots of nitrogen, but most living things can’t use the nitrogen in the air to make protein. So, bacteria living on plants change that nitrogen in the air into a form that plants and animals can use (nitrates). When living things die, they are decomposed by bacteria and fungi, which releases nitrates into the soil. Nitrates are left in the soil and can be used by plants to make protein. Some plants are eaten by animals, who in turn create proteins from those nitrates. The bacteria on the plants will change the nitrates back to nitrogen. When plants or animals die, the nitrogen in their bodies returns to the soil. Some nitrates in the soil are changed back into nitrogen gas by bacteria and released into the air.

Predator-Prey What are your predictions to the following situations? –What would happen to the predator population if the prey population increased dramatically? –What would happen to the prey population if the predator species contracted a deadly disease? Sample Answers: The predator population would grow because there is more food/prey. The prey population would grow because there are fewer predators to eat them. Eventually the prey population would grow too large, consume all of their resources and crash.

Predator- organism who feeds on other organisms Prey- organism eaten by another organism

Symbiosis Symbiosis- a long term relationship between different species living in close association with one another

Types of Symbiosis Parasitism (parasite-host)- one organism benefits, the other is harmed Commensalism- one organism benefits, the other is unaffected Mutualism- both organisms benefit (not symbiosis): Predation (Predator-Prey)- one organism benefits, the other is killed/eaten

Easy way to remember it: [Predation- (Predator-Prey):] Parasitism- (Parasite-Host): Mutualism: Commensalism: (NOT symbiosis)

Succession- a process that comes after, or next Ecological succession- the replacement of one type of community by another at a single location over time –Ecosystems change over time, and may gradually develop into new ecosystems

Mt. St. Helens Before Eruption Immediately After Eruption Several Years After Eruption

Succession begins when a pioneer species/plant invades an area where plants have not grown before. As this species grows, it alters the environment, making it more favorable for new species to invade and grow. Eventually, over time, the community will reach a stable stage, and succession stops. Examples of stable communities are grasslands, deserts, and coniferous, deciduous, and tropical forests (climax communities)

Niche Niche – the role or “job” of an organism within its ecosystem. This includes where it lives and what it does. Ex. The niche or “job” of a black snake would be to serve as a predator in a forest environment. The niche of a fungi might be to break down (decompose) dead plants and animals to recycle their nutrients back to the ecosystem.

Black snake in its niche

Fungi in its niche

Can you spot the organism? What is its niche?

More snake pictures…