Chapter 2 SECTION 2 NUTRITION AND ENERGY FLOW
Autotrophs • Organisms that use energy from the sun or chemicals to make their food
Heterotrophs • Organisms that depend on autotrophs for nutrients and energy.
Types of Heterotrophs • Carnivores • Herbivores • Scavengers • Omnivores • Decomposers
Carnivores • Only eat meat
Herbivores • Only eat plants.
Scavengers • Feed on carrion, refuse, and similar dead organisms
Omnivores • Eat a variety of plants and animals
Decomposer • Break down complex compounds of dead and decaying organisms into small, absorbable molecules.
Food Chain • A model that shows how matter and energy move threw an ecosystem.
There are usually no more than 5 links because the amount of energy has been dissipated.
Trophic Levels • A feeding step in a food chain. • Many different species occupy each trophic level in an ecosystem. • Many organisms feed from several different trophic levels.
Food Web • Food webs express all of the possible feeding relationships in at each trophic level in a community.
Ecological Pyramids • Show energy conversion in a ecosystem. • Pyramid of energy - energy decreases at each higher trophic level. • Pyramid of numbers - population size decreases or increases at each higher trophic level.
Pyramid of Energy • The total transfer of energy from one trophic level to the next is 10%. What happens to the rest of the energy?
Pyramid of Numbers • Can you think of an example where the pop. Size will increase at each higher trophic level?
Cycles In Nature • Matter is cycled through the environment. Now we will see how water, carbon, nitrogen and phosphorous cycle through the environment.
The Water Cycle • Water is necessary for life. • Water moves between the Earth and the atmosphere by the processes of evaporation, transpiration, condensation and precipitation.
The Carbon Cycle • All living things contain carbon. • Autotrophs change CO2 into food that animals can eat. • Plants and animals return carbon to the atmosphere during respiration. • Dead organic matter becomes fossil fuels that return carbon to the atmosphere when burned.
The Nitrogen Cycle • Nitrogen in the atmosphere is turned into a form that plants can use to grow and make protein. • Animals eat plant protein and make animal protein and waste products. • Dead plants, animals and waste products return nitrogen to soil. • Nitrogen in soil is released into atmosphere.
Phosphorous Cycle • Phosphorous makes up phosphates. Phosphates are contained in nucleotides, which are contained in ATP, and the nucleic acids DNA and RNA. Phosphorus is also found in bones, whose strength is derived from calcium phosphate, and in phospholipids (found in all biological membranes).
The Phosphorous Cycle • Plants get phosphorous from the soil. • Animals get phosphorous from eating plants. • Dead decaying animals return phosphorus to the soil. • Phosphorous is contained in rocks that can be weathered and returned to the cycle.