describe, using specific examples, how the theory of evolution is supported by the following areas of study:
Background
Palaeontology is the study of fossils. Fossils are preserved traces of past life on Earth, mostly found in sedimentary rocks. Fossils can include preserved body parts, moulds and casts of decayed organisms, and imprints left in mud such as footprints.
Preserved material less than 10 000 years old or hand-made objects such as arrowheads are not considered fossils, they are artefacts.
Palaeontology
Of particular interest are transitional fossils that have characteristics belonging to ancestral and descendant groups. The most famous transitional form is Archaeopteryx. This is a fossil first thought to be a therapsid reptile. Its reptilian features include teeth and a reptilian-like skeleton. However, Archaeopteryx also had feathers and a wishbone sternum used to attach flight muscles. This provides evidence of an evolutionary pathway from dinosaurs to birds.
Transitional Fossils
Archaeopteryx: an early bird, Museum of Paleontology, University of California, Berkeley, California, USA
Biogeography
Comparative embryology
Embryonic Development Animations of embryos, NOVA Online PBS Broadcasting, USA
Comparative anatomy
An example of an homologous structure is the pentadactyl limb found in amphibians, reptiles, birds and mammals. The basic plan consists of one bone in the upper limb, two in the lower limb leading to five fingers or toes. In bats, the limb is modified to form a wing with the fingers extended and skin stretched between each finger. Whales have within their single paddle-like fin a fully formed pentadactyl limb.
Homologous structures BioWeb 9-12, USA
Biochemistry
The study of amino acid sequences shows that more closely related species share more common sequences than do unrelated species. Particular evidence has been derived from the amino acid sequence in haemoglobin, showing that humans and rhesus monkeys share all but eight amino acid sequences whereas there are 125 amino acid differences between humans and lampreys. This supports the fossil, embryological and anatomical evidence that humans are more closely related to rhesus monkeys than they are to lampreys.