Tuesday, May 10, 2011

4.7 explain why only about 10% of energy is transferred from one trophic level to the next.

Energy efficiency

Mammals & birds maintain a constant body temperature using energy released by respiration. Consumers at each level convert on average only about 10 percent of the chemical energy in their food to their own organic tissues. 10 percent of this energy is transferred between each trophic level. 




4.6 understand the transfer of substances and of energy along a food chain

Energy Transfer

When herbivores eat green plants they are taking energy into their bodies. The herbivore will use this energy for movement & other body activities, eg: reproduction

Parts of the plant which was eaten cannot be digested by the herbivore; the energy in these parts passes out  as waste. Some of the energy,  is used for growth & remains as organic matter in the herbivore's body. It is this energy which can be eaten by the secondary consumer.
Stored energy is eaten by the secondary consumer

Only a very small amount  of the producer's original energy is stored by the secondary consumer. This energy is taken into the body of the tertiary consumer. So  the amount of energy available for the tertiary consumer is only very little of the energy which the primary consumer gained from the plant.

Monday, May 9, 2011

4.5 understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy transfer

Food chain: In order of rank, a series of organisms each dependent on the next as a source of food.

Food webs: In an ecosystem there are many different food chains & many of these are cross-linked to form a "food web."

Pyramids of number:  The Number pyramid shows the number of organisms in each trophic level + the higher up it goes, there are fewer organisms than the level below it.

 Biomass Pyramid:  This pyramid indicates the total mass of the organisms in each trophic level.The total biomass at a particular step in a food chain is always less than the total biomass at the step before it.

Pyramid of energy transfer:  The Energy pyramid indicates the total amount of energy present in each trophic level. It also shows the loss of energy from one trophic level to the next.

An energy pyramid shows clearly that the energy transfer from one trophic level to the next is accompanied by a decrease due to waste and the conversion of potential energy into kinetic energy and heat energy.

4.4 recall the names given to different trophic levels to include producers, primary, secondary and tertiary consumers and decomposers

Trophic levels are the feeding position in a food chain such as primary producers, herbivore, primary carnivore,etc.

1st. Photosynthsis (green plants) They're the "producers"
2nd. Herbivore - animal that feeds on plants. Known as "Primary Consumers"
3rd. Carnivore - animal that feeds on flesh. Known as  "Secondary Consumers"
4th. Top carnivore - the biggest animal - known to be at the top of the food chain. Known as "Tertiary Consumers"

The levels work in a sequence of feeding of one animal upon another in food transfers.
Begins  with light energy from photosynthesis from plants, then being eaten by herbivores the energy is changed to chemical energy.

Example of a food chain: rose plant -- aphids -- beetle -- chameleon -- hawk. This followers the labeled numbers above.
Eventually for example like the hawk  dies and its remains are broken down by decay-causing bacteria and fungi.

Sunday, May 8, 2011

4.3 describe the use of quadrats as a technique for sampling the distribution of organisms in their habitats.

Quadrat technique used to sample the pop of species.

Sample: Random (Bias)
             Representative (Large) 
How they organize: Grid system. This enables you to identity all material - Works like a graph using coordinates. The guadrats are placed in the grid in individual squares - for placement  for "Bias" sampling, you use "random" numbers and they are generated along the "x" & "y" axis.

Representative sampling : A small quantity of materials, whose characteristics represent (as accurately as possible) the entire batch,population.

4.2 recall the use of quadrats to estimate the population size of an organism in two different areas

Quadrat:  is a tool used in ecology for sampling purposes, so that populations of species can be compared.  Eg, a quadrat is placed on ground at random to count the vegetation within the sample taken.

Recap: All ecosystems are made up of a population which form a community + the habitat.

Calculating the pop size of an organisms using "quadrates" - It is important in the design method to add all the individual organisms in the habitat & to separate the land into two different areas. Often labeled "A" & "B." Eg: In a sand dune. Area marked A would be in the grazed area, & area marked B in ungrazed.

4.1 understand the terms: population, community, habitat and ecosystem

Ecosystem = "Community" of animals, plants and microorganisms, together with the habitats where they live.
Can be: covering a small area (eg pond) or covering a large area (eg: a tropical rain-forest).
-The world is divided up into ten major ecosystems. These large-scale ecosystems are called biomes.
Habitat =  The place being occupied by an organism, population, or community. A habitat ontains all the "Antibiotic" factors - such as, daylight/dark + temp + rainful + humidity + slope.

Population: pop of different species.

"Species" are also called "organisms." Which reproduce fertile offspring. The interaction most common that happens between is "feeding."

Examples of ecosystems.