Darwin first presented his theory of evolution by natural selection through his book called ‘On the Origin of Species’. The book was released in 1859 and it explained the process of how organisms changed over time through the result of changes in heritable physical or behavioural traits. These changes allow an organism to adapt to the environment that it inhabits so that the organism’s chances of survival improve and produce more offspring (Than, 2015). However, biological evolution does not simply mean a change over time. It is believed that the central idea of biological evolution is that all organisms on Earth share a common ancestor (Understanding Evolution, 2015).The major principles of Darwin’s Theory of Evolution by Natural Selection …show more content…
In order to determine the age of a rock, it ‘involves using minerals that contain naturally-occurring radioactive elements and measuring the amount of change or decay in those elements to calculate approximately how many years ago the rock formed.’ Radioisotope dating is accurate because the rate of emission or decay is measurable and is not affected by external factors (Pojeta & Springer, 2001). Ever since Darwin proposed his theory, new evidence has appeared to attempt to validate his theory, such as the use of radioisotope dating on the cave formations of the Grand Canyon. Radioisotope dating, specifically uranium-lead dating, not only supports the geologic ‘evolution’ of the Grand Canyon, it also validates a central principle in the theory of evolution (Carlton, 2015). Darwin’s theory of evolution was criticized for its requirement for ‘an almost infinite number of generations’. At the time, ‘the evidence suggested that earth was less than 100 million years old.’ However, after around 50 years since Darwin published ‘On the Origin of Species,’ evidence suggested that the earth was old enough to contain complex organisms. This was found through the research on radioactive elements found in rocks (Carlton, 2015). Radioisotope dating has provided evidence for evolution from fossil records. Dating the …show more content…
The apple maggot fly was originally a hawthorn fly until the mid-1800s. The adults would meet at hawthorn fruits to mate and lay eggs. However, when apples were introduced into their habitat in North America, some of the haw flies found the apples as an attractive place to gather. The flies began to mate and lay their eggs on apples instead. Today, the flies that like apples and the flies that like haw have become genetically distinct. The reason is that when flies look for a mate they meet at the fruit that they prefer, therefore haw-preferring flies would most likely meet other haw-preferring flies, the same goes for apple flies. These mating preferences also show how the haw and apple flies differ in survival. ‘Attributes that help maggots survive on haw are different from those that promote survival on apples. Apple trees produce fruits earlier than hawthorn, and apple-specialists must thus emerge from their pupae earlier, or they risk missing the fruit’ (Judson, 2008). Since the emergence of the flies is under genetic control, the apple and haw flies would certainly have genes that incline them to emerge at different times (Judson, 2008).

According to Encyclopaedia Britannica, comparative anatomy is ‘the comparative study of the body structures of difference species of animals in order to understand the adaptive changes they have undergone in the course of evolution from