Distinguish between r-selected and k-selected species and give an example of each type. define population density and explain why it can affect the size of some but not all populations.

K-selection aims to achieve equilibrium

r-selection aims to have achieve the best gene combinations

Population density is Organism/per square kilometer or square mile

Explanation:

r-selection aims to have achieve the best gene combinations by the rule of survival of the fittest therefore r-selected species have high reproduction rates and large populations. Most insect species can be given as an example to r-selection.

K-selection aims to achieve equilibrium in the habitats it is applied in. Therefore K-selected species have lower reproduction rates and live in smaller numbers but are highly competitive and have larger bodies unlike the r-selected species. Most large animals can be given as an example to K-selection including humans.

Population density is calculated by dividing the number of organisms living in a certain area to the area and gives us how crowded that certain area is by Organism/per square kilometer or square mile.

It can affect the size of certain populations which include organisms who have higher reproduction rates and cannot fit in that area so it sort of puts a limit to the total number. If the species are able to spread and have the ability to live in different conditions and climates like humans then population density has no effect on the size of the population even if it increases.

I hope this answer helps.

phylogenetic tree is the tree of life or evolution tree. it shows the different branches of evolution. the sequence goes like tissues - coelom - backbone - endoskeleton - segmentation