Topic 4 How organisms react

An Ecosystem

An Ecosystem Biotic – the living things in the ecosystem. Abiotic –the non living things in an ecosystem. How does a hare interact with biotic and abiotic parts of its ecosystem?

List 5 biotic and abiotic parts of the ecosystem shown

Roles of Organisms A NICHE is the role of an organism in an ecosystem: What it eats What eats it Where it lives How it interacts with other animals (symbiosis)

Roles of Organisms Producers vs. Consumers Producers photosynthesize, and use carbon dioxide, water, and the sun’s energy to produce glucose (food) and oxygen. Photosynthesis Consumers- Eat other living things for energy and breathe our carbon dioxide.

Roles of Organisms Consumers may also be: Some Consumers will be: Herbivores – plant eaters Carnivores – meat (other consumers) eaters Omnivores – eat plants and animals (other consumers) Some Consumers will be: Predators – do the eating Prey – Are eaten by predators

Name an organism for each niche: Producers Consumers Herbivores Carnivores Omnivores Predators Prey

Food Chains Food Chains show how stored energy passes from organism to organism What direction do the arrows point to?

Create a Prairie Food Chain:

Pyramid of Numbers Shows the organisms of a food chain but represents the number of organisms to meet the energy needs of the next level

Biomass Biomass- is the total mass of all the organisms in an ecosystem. Bio mass can also be represented in a pyramid form. Why?

Scavengers and Decomposers Scavengers eat and live off of dead organisms and wastes.

Scavengers and Decomposers

Scavengers and Decomposers Decomposers- Are small organisms that live on or in dead materials to absorb nutrients They recycle dead organic matter back to the earth Bacteria and fungi Worms Maggots Insects

Did you know? Right now trillions of bacteria are decomposing your body, by growing on your skin, and are constantly breaking dead skin cells down into common household dust?

Composts Composts are a way to speed up natural decomposition Many kitchen wastes can be broken down in a compost Small bacteria break down the wastes into nutrient rich soil called top soil

Topic 5 Cycles in the Environment

Carbon Foot Print Burning of fossil fuels that contain carbon is linked to global climate because it produces carbon dioxide, a greenhouse gas.

The Carbon Cycle All living things are made from carbon – it is necessary for life to exist. Plankton are microscopic plants and animals Phytoplankton are microscopic plants Zooplankton are microscopic animals. Decomposing plankton under pressure can be converted to fossil fuels. Fossil fuels contain carbon.

The Carbon Cycle Plants use carbon dioxide to make glucose or sugar which also contain carbon that we eat from plants. Our bodies tissues are made from carbon as well, and when we eat other animals we convert that carbon into tissues like muscles. We also breathe out carbon dioxide As living organisms die and break down the carbon breaks down and changes form.

Carbon constantly changes form and cycles through the environment

The Water Cycle All living things need water. We are 70% water. Water: Helps to break down food for energy Makes up much of our cells Carries away waste Water Cycle

Water Cycle The water cycle is the continuous movement of water through an ecosystem. Water cycles as: Evaporation- liquid to gas Transpiration- liquid to gas but by plants (tree sweat) Condensation- gas to liquid (clouds) Precipitation – gas to liquid but as rain or snow Ground water and run-off contribute to the movement and cycle of water too

Pollution and the Environment Pollution- occurs when a substance added to the environment cannot be broken down, stored or recycled by the air, land or water to be converted to non damaging forms. If pollution gets too high it harms organisms. Pollutants- are substances that cause pollution. Carbon dioxide is natural but burning fossil fuels has caused it to accumulate in the atmosphere.

Pollution – Acid Rain Sulfur and nitrogen come from burning coal and fossil fuels, as well as from our cars. These produce too much sulfur and nitrogen. When sulfur and nitrogen mix with water in the atmosphere the rain becomes acidic. When this rain falls and damages crops, corrodes metals, and is especially toxic to fish eggs. If the pH falls below 5.6 many of the organisms in a lake will die.

The Statue of Liberty

pH scale

Pollution PCB’s (Polychlorinated Biphenyls) Mercury Used to cool power lines Used in paints PCB’s have shown up in our water They are toxic and are linked to cancer They can contaminate soil and water for decades. Mercury Use in gold mining and other industries like pulp and paper. Cause severe nerve damage in humans and other animals. Causes brain damage

Pollution – Mercury

Pollution - DDT Was a very effective pesticide Banned in the 80’s when it was linked to the weakening of eggs of large birds like the bald eagle. Not water soluble No known toxic effects in humans.

Pollution – Bioaccumulation Bioaccumulation (biomagnification) Toxins become more and more concentrated as you move up the food chain. Why does this happen?