Ecology – Part 1 The Cycling of Matter and Energy in Ecosystems General Biology Name__________________

There is a flow of materials and energy throughout every ecosystem

There is a constant flow of materials and energy between the living (biotic) and nonliving (abiotic) parts of every ecosystem. Materials (atoms, molecules) must be recycled but energy is NOT! So, a constant supply of energy must enter every ecosystem. On earth, this is supplied by the SUN!

Remember, organisms must be able to: produce or obtain nutrients convert the nutrients into usable forms of chemical energy (cellular respiration – producing ATP!!) use these forms of energy to power their life processes.

2 Categories based on how living things produce/obtain nutrients…. Heterotrophs Autotrophs Obtains food by consuming other living things CONSUMER Ex: Animals, fungi, some microorganisms (bacteria) Categories: Herbivores, Omnivores Decomposers Capture energy from sunlight or chemicals and use it to produce its own food from inorganic compounds PRODUCER or Primary Producer Ex: All Plants, some microorganisms (bacteria)

Decomposers & Detritivores in Food Webs Convert dead/waste material into detritus Eaten by detritivores Ex: Grass Shrimp, Crayfish, Worms Decomposers releases nutrient that can be used by primary producers Nature’s Recyclers Without them – nutrients would remain locked in dead organisms Examples: Bacteria & Fungi

Matter is recycled, energy is not…

Water Cycle All cells need water to live!! Rain/snow – water falls to earth Water runs into rivers, ponds, oceans Water soaks into soil Plants & animals use water; the rest flows into underground lakes/rivers Plants/animals lose excess water (plants – transpiration; animals – evaporation) to the air Evaporation from lakes, rivers, oceans Condensation – water vapor turns to liquid

Oxygen-CO2 Cycle OXYGEN Given off by producers during photosynthesis Used by all living things during respiration CARBON DIOXIDE Given off during respiration Used by producers during photosynthesis This cycle goes on in both land and water ecosystems.

Nitrogen Cycle Nitrates – chemical in soil that contain nitrogen. Needed by plants to make proteins. NITROGEN CYCLE (repeating steps) Bacteria on roots change N in air into nitrates in soil. Nitrogen in dead organisms changes to nitrates in soil. Nitrates can be used by plants/animals to make proteins. Bacteria change some nitrates in soil back into nitrogen in air.

What did we learn so far? The sun is the ultimate source of energy for most ecosystems. As a result, organisms exhibit different strategies to obtain this energy. Energy relationships can be represented in a graphical depiction called a pyramid. Elements cycle in various molecular forms through the bioshere. The carbon, oxygen, nitrogen and water cycles are examples essential to life. Matter cycles through food chains but energy must be continually supplied. There are varying levels of biodiversity found in the different biomes.