Topic 5: Ecology and Human Impact

What is Ecology? Ecology: The Study of organisms and their environment. Habitat: Where an organism lives Niche: The organisms role in the environment. Everything an organism must do to survive. Two species in an ecosystem trying to fill the same niche will create competition, which usually results in one species occupying a niche at any one time. Organisms with similar needs will often divide resources to reduce competition (ex. Birds eat insects during the day, bats eat them at night

How organisms interact with each other: Competition: occurs when two or more organisms need the same resource. Ex: A squirrel and a chipmunk compete for food. Feeding: One organism feeds on another. Producer – An autotroph; organisms that makes its own nutrients from simple substances. Consumer – A heterotroph; may be an herbivore, carnivore, omnivore or decomposer. Symbiosis: A close relationship between two organisms in which at least one benefits. Can include 2 organisms working together for mutual benefit (bee and flower) or 1 organism harming another (parasite-host).

Abiotic vs. Biotic Abiotic Factors: Non-living things Biotic Factors: Living thing  Organisms interact with the biotic (living) and abiotic (non-living) parts of their environment through food webs and nutrient cycles.  

Ecological Levels of Organization  

Populations A given area can only supply enough resources for a limited number of organisms. Carrying capacity: The largest population an ecosystem can support.

Limiting factors: Anything which limits the size of a population, including: Food, water, sunlight, soil, predators, disease, dissolved oxygen  Overpopulation: When a population exceeds the carrying capacity. Usually results in a large number of organisms dying off until a new balance is reached.

This is the most important part of the test!!! Energy is needed to keep an ecosystem going. The energy comes from the sun and is made usable by producers (plants and other autotrophs)

Energy in an Ecosystem Sunlight provides all energy for life on Earth.   Sunlight provides all energy for life on Earth. Sun’s energy is stored in the chemical bonds of food through the process of photosynthesis Food chain – Shows 1 way that energy can “flow” through an ecosystem. Energy in an Ecosystem

Food Web Food web – Shows many energy pathways. Energy pyramid: Shows that energy gets lost with each step in a food chain Energy is lost because every organism uses some of the energy for it’s own life processes. Only about 10% of energy is passed from one step to the next. This is why populations of predators are typically less than the populations of their prey.

Food Web and Pyramid

Biodiversity refers to the variety of life on earth Biodiversity refers to the variety of life on earth. As habitats are lost and species become extinct, biodiversity is reduced. This is considered to be bad because: Ecosystems with low diversity are less stable than ecosystems with more diversity Ecosystems with low diversity take longer to recover from environmental changes We use organisms for many things such as food and medicine; by reducing biodiversity we are losing potentially valuable resources. Biodiversity

Ecological Succession Ecological Succession: Process by which existing communities are gradually replaces by a series of new communities. The organisms in each stage of succession change the environment, and allow new organisms to move in and replace them.

B. Climax Community: Final stage of succession The climax community is determined by the local climate. Ex: Kansas has very fertile soil, but not enough rain to support trees, so succession stops with grasses and shrubs. C. Any temporary disruption of a community will begin the process of succession all over again. Ex: If a forest fire kills all the trees in an area, succession will eventually return the area back into a forest, but it much first pass through all the necessary stages

Define the following terms: producer organism that makes its own food consumer organism that gets food by consuming other organisms omnivore organism that eats animals and plants

Definitions herbivore organism that only eats plants carnivore organisms that only eats animals predator animal that hunts and kills for food parasite organisms that lives on or in a host and harms it

Definitions place where an organism lives habitat place where an organism lives niche the role of an organism in its environment population a group of the same species living in a defined area community a group of populations living in a defined area ecosystem all the living and non-living things in a particular area

Definitions biosphere the combined portions of the planet in which all of life exists, including land, water, and air or atmosphere pollution harmful materials that can enter the biosphere renewable resource resource that can be replaced after a short time or reused

Human action (development, industrialization, pollution, farming, over-hunting, overgrazing, clear cutting, introduction of foreign species, soil erosion) often has negative consequences for the ecosystem (and humans too). Human Impact

Human Impact The negative effects humans have had on the environment are mostly due to the increasing human population. habitats are decreasing to make room for buildings and homes more wastes are produced

Actions being taken by humans to reduce or repair damage to the environment include: Recycling wastes Conserving available resources Using cleaner resources (ex: solar over fossil fuels) Protection of habitats and endangered species Positive Human Impact

Positive Human Impact Use of biological controls instead of pesticides and herbicides Farming native plants (ex: cocoa in the rainforest) Planting trees to replace those cut down. Rotating crops or planting cover crops to reduce soil loss. Passing laws to control pollution, land management, hunting, fishing, etc.

Environmental Issues For each of the following ecological problems, identify the specific cause, their negative effects on the environment, and a way that people are trying to fix the problem: Acid Rain cause nitric and sulfuric acids released by industry negative effect can kill plants, pollute water fixing place filters on smokestacks

Environmental Issues Loss Of Habitat (Ex: Deforestation) cause cutting down trees negative effect erosion of soil, loss of habitats, less CO2 being removed from the atmosphere fixing engage in selective cutting practices, recycle paper

Environmental Issues Loss Of Diversity cause habitat destruction/fragmentation negative effect unstable ecosystems fixing nature preserves, laws protecting

Environmental Issues Global Warming cause increase in carbon dioxide in the atmosphere due to burning o fossil fuels negative effect ice caps melt, more severe weather fixing use alternate energy sources

Environmental Issues Loss Of Ozone Layer cause use of CFC’s (chlorofluorocarbons) negative effect less protection from UV radiation fixing ban the use of CFC’s

Environmental Issues Introduced Species (Invasive Species) cause foreign species accidentally or purposely brought into a habitat by humans negative effect out-compete native species fixing increase natural predators