Ecosystems

What is an ecosystem? All the biotic and abiotic factors in a specific area Biotic factors-All the living organisms in the ecosystem Abiotic Factors-All the non-living things in the ecosystem

Biotic Factors In an ecosystem many different types of organisms live together A population is a group of the same species of organisms that live in the same area For example, a squirrel population would include every squirrel in the area

Biotic Factors Different populations fill different roles in the ecosystem Producers-make sugar from sunlight Consumers-get their energy from other organisms Decomposers-break down waste and dead organisms

Energy Flow All energy for an ecosystem comes from the SUN Producers turn sunlight into sugar They use that energy to grow and develop Consumers come along and eat the producers to get the sugar they store Other consumers eat those consumers to the energy they took from the producers

Food Chains A food chain is a way of describing who eats who in an ecosystem

Food Chains Predators- organisms that eat others Prey- organisms that are eaten by others Arrows in food chains start at the prey and point towards the predator

Food Webs A Food Web shows all of the food chains that occur in an ecosystem Consumers normally eat more than one type of food, and food webs let us see how the whole system works

Draw a food web for organisms in your neighborhood

Abiotic Factors Anything that is not alive, but is still part of the ecosystem is an abiotic factor There are 3 really important abiotic factors Water Carbon Dioxide Nitrogen

Water Cells are mostly made of water Without water cells do to not work correctly Water moves through an ecosystem in a predictable way, called a cycle

The Water Cycle The sun makes water evaporate (gas) The gas condenses (liquid) to make clouds Clouds start precipitation (rain, snow) Precipitation forms runoff as the water goes back to lakes and oceans

Pollution & the Water Cycle Human activity (farms, factories, trash) can affect the water on the planet When it rains, the water crosses the ground and picks up all the stuff that is on the ground (runoff) The water then carries those contaminants to the rivers, lakes and oceans

The Carbon Cycle Plants take in Carbon Dioxide Plants make sugar and oxygen (photosynthesis) Animals eat plants and breathe oxygen Animals use respiration to get energy Animals breathe out Carbon Dioxide

The Carbon Cycle Carbon is the most important atom for living things It is used to make cells, proteins and store energy Organisms use the carbon they take in through the cycle to build their bodies Without Carbon, organisms could not grow and develop

The Nitrogen Cycle Nitrogen is in the air free nitrogen (N2) Bacteria change it to fixed nitrogen (NH3) Plants take in fixed nitrogen Consumers eat plants and take in fixed nitrogen Decomposers break down dead consumers Decomposers release free nitrogen (N2)

Nitrogen Cycle Organisms need Nitrogen to build their DNA If there is not enough Nitrogen to copy the DNA cells will not divide If cells do not divide, the organism cannot grow This is why farmers use fertilizer to add Nitrogen to the soil More nitrogen means more DNA can be made, which means more cells can divide