What is selective pressure.

Selection pressures are external agents which affect an organism’s ability to survive in a given environment

Selection pressures can be negative (decreases the occurrence of a trait) or positive (increases the proportion of a trait)

Selection pressures may not remain constant, leading to changes in what constitutes a beneficial adaptation

Types of selection pressures include:

Resource availability – Presence of sufficient food, habitat (shelter / territory) and mates

Environmental conditions – Temperature, weather conditions or geographical access

Biological factors – Predators and pathogens (diseases)

tsd is temerature dependent sex determination.

tsd: it is a type of environmental sex determination in which the temperature experienced during embryonic/ larval development (ambient temperature for development) determine the sex of the offspring.

crocodile displays the tsd where the ambient temperature of the developing egg determines the individual's sex. for example in the american alligator's eggs, incubation at 33 ºc produces mostly males, while incubation at 30 ºc produces mostly females. so if the american alligator's egg will get the ambient temperature (33 degree celcius)during embryonic development from egg, the offspring will be male and same for the female sex determination.

a scenario where a cell may be needed to perform a form of endocytosis is when transporting large molecules. a scenario where a cell may be needed to perform a form of exocytosis is when releasing the large molecule from the cell.