Summarize Darwin’s theory of natural selection using the Galapagos tortoise or finches as an example. SC.7.L.15.2

The theory of natural selection, formulated by Darwin, explains how organisms with better characteristics are able to survive and reproduce. According to the theory of Darwin, genetic variations occur among organisms of a species. Those organisms which have better adaptations to survive in the environment are able to survive and pass on their traits to their offsprings. The organisms not having better characteristics are not bale to survive and those traits get completely removed through the process of evolution.

For example, Darwin studies showed that The Galapagos island comprised of 13 different kinds of finches on different islands. The main difference between these finches was their beaks. The differences in the beaks occurred due to the different modes of nutrition in the finches of different islands.

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.