Chapter 5 Page 98 Trophic Levels

All ecosystems do 2 things: 1. Transfer Energy 2. Cycle matter

Transfer Energy (Most ecosystems use Sunlight as its source, but some use inorganic molecules) Moves from: Sun – it’s source – into organisms – then into space as heat.

Transfer of Matter Recycled Carbon, oxygen, and other elements

4.1 Roles of Living Things Each living thing in the environment plays a different role in the flow of energy and matter.

Producers “organisms that make their own food from inorganic molecules and energy” PLANTS! Create sugars thru PHOTOSYNTHESIS

Ways to gather food… Producers Consumers Decomposers

TYPES OF PRODUCERS TERRESTRIAL Plants are the most important producers AQUATIC Small photosynthetic protists and bacteria are the main producers Few nonphotosynthetic producers like bacteria that live in harsh envt’s

CONSUMERS “organisms that cannot make their own food” Ex - Animals, fungi, protists, bacteria Obtain energy by eating other organisms

HERBIVORE “eats only producers” Insects, cows, etc 4 TYPES OF CONSUMERS HERBIVORE “eats only producers” Insects, cows, etc CARNIVORE “capture and eat herbivores or other carnivores Secondary consumers, etc. Adapting to hunting, capturing, and eating prey OMNIVORE “eats both producers and consumers” Humans Primary consumer, 2ndary consumer SCAVENGERS “don’t hunt living prey, but feed on dead orgs.” Dead plants, animals,etc Begin the return of nutrients

Decomposers “Consume the bodies of dead organisms and other organic wastes” Ex – bacteria, fungi Recycle nutrients back to the soil Complete the cycle of matter

TROPHIC LEVELS “layer in the structure of feeding relationships in an ecosystem”

Levels First layer = Largest layer Producers Autotrophs 2nd + layers= Heterotrophs Herbivores = (Primary consumers) Carnivores = (2ndary consumers,etc)

4.2 Ecosystem Structure “the interactions between trophic levels form a chain that links the organisms in an ecosystem.”

Food Chains “A series of different organisms that transfer food between the trophic levels of an ecosystem”

Levels of Consumers Producers always on bottom 1st level of consumers 2nd level of consumers, etc

Food Chains ALWAYS begins with PRODUCERS on the bottom (usually plants) Next layer would contain the HERBIVORES Next layer(s) would contain CARNIVORES

FOOD WEB “Network of food chains representing the feeding relationships among the organisms in an ecosystem”

FOOD WEB Includes all the food chains in an ecosystem Webs don’t usually show the decomposers at the top of the web. Changes in the population of one organism can affect many other populations.

Diversity and Stability Some biologists think that a food web with MORE links can withstand changes/instability better than one with only a few links.

Biological Magnification “the increasing concentration of a pollutant in organisms at higher trophic levels in a food web” Pollutants become concentrated in the bodies of consumers the higher up the chain it goes SINCE THEY EAT MORE! Therefore intake of a few organism can affect the whole food web.

4.3 Energy in the Ecosystem Energy is limited and affects the structure and function of the food web.

ENERGY AND FOOD Energy comes from the sun Some energy reflected back, and some absorbed. Plants receive less than 1% of energy that reaches earth. 30% of this energy is stored in organic matter from photosynthesis This makes 170 billion tons of organic matter a year.

Biomass “TOTAL AMOUNT OF ORGANIC MATTER PRESENT IN A TROPHIC LEVEL”

BIOMASS Basically, biomass is the potential food for the next trophic level. Most energy is lost before it is passed to the next trophic level. This loss of energy explains why there is a limit to the number of trophic levels an ecosystem can support.

Ecological Pyramid “diagram that shows the relative amounts of energy in different trophic levels in an ecosystem” Can show energy, biomass, or number of orgs.

4.4 Cycles of Matter Water Cycle Carbon Cycle Nitrogen Cycle

Water Cycle Moves between the ocean, atmosphere, and land Evaporation = movt of water into the atmosphere as it changes from a liquid to a gas Transpiration = evaporation of water from the leaves of plants ex -Rainforest = amount affects its climate! Precipitation = water in atm returns in rain, snow, sleet, or hail.

Reclaimed Water?

Carbon Cycle Early earth = 95% CO2 Now is only .04% thanks to photosynthesis Present in 3 main sources: 1. living things 2. oceans = CO2 dissolves in water easily 3. rocks = fossil fuels

Nitrogen Cycle Living things need Nitrogen to make Amino Acids = Proteins Can’t use the N gases present, but in a different form. Therefore Nitrogen Fixation must occur!

Nitrogen Fixation Use the N gases to make ammonia(NH3) which plants can use Nitrogen- fixing Bacteria Some bacteria live on plant roots. These plants are called LEGUMES. (peanuts, beans)