Oh Deer!

Desity-dependent and Density-independent Factors

Many factors affect the ability of wildlife to survive over time. Weather conditions, disease, predators, pollution and habitat destruction are some examples. Habitat is the key to wildlife survival and population size.

For the purposes of this exercise, habitat is defined as food, shelter and water. If any one of them is lacking or restricted in availability then wildlife numbers are reduced. In the accompanying exercise, students learned that organism numbers will be governed by the availability of habitat elements.

The class was divided into two groups of deers and resources.  Each round the deers decided whether they are hungry, thirsty or cold so they could make the related symbols.  The other team of students decides whether they are food, water or shelter (Destity-independent factors) and they make the same symbols. The deer then ran across the space and caught their food, water or shelter. Only one deer per person. If there were more deer that need water than there were ponds, then the deer died and stayed on the side of the necessities. The deer that got what they need, reproduced and took their new deer with them back to the deer's team. After each round an equlibrium was reached between the resources and the population of the deers.  After a while, deer population was hit by Density-dependent factors such as forest fore, drought and predators.  These factors could actualy lead the population of deers to an extinction while density-independent factors led the population to an equlibrium. 



Photosynthesis and Cellular Respiration

Kerb Cycle

Kerb Cycle

The Krebs cycle refers to a complex series of chemical reactions that produce carbon dioxide and ATP. The cycle occurs by essentially linking two carbon coenzyme with carbon compounds; the created compound then goes through a series of changes that produce energy. This cycle occurs in all cells that utilize oxygen as part of their respiration process. Carbon dioxide is important for various reasons, the main one being that it stimulates breathing, while ATP provides cells with the energy required for the synthesis of proteins from amino acids and the replication of DNA; both are vital for energy supply and for life to continue. In short, the Krebs cycle constitutes the discovery of the major source of energy in all living organisms.