Question

Discuss four evidences to show that evolution has taken place.

Answer 1

1. Fossil records.
   • Fossils are remains of dead organisms preserved naturally. They indicate that organisms have evolved from simple life forms to most complex forms. Fossils of human beings indicate that the modern human being has a highly developed brain and uses speech for communication unlike the early human being. Fossils of horses show that the modern horse is 1.5m high, lives in dry grassland, teeth are adapted for chewing and it stands on one digit whose distal end is converted into hoof.
2. Comparative anatomy.
   • This involves comparing the form and structure of different organisms. Some groups of organisms show basic structural similarities suggesting common or related ancestry showing divergent evolution. Other groups of organisms show morphological similarities but are found to have different ancestry showing convergent evolution;
3. Comparative embryology.
   • Studies show that embryos of fish, birds, amphibians, reptiles and mammals are morphologically similar during the early stages of development but with time they develop and change to look like their parents;
4. Geographical distribution (continental drift)
    
   • Regions with similar climatic conditions and lie in the same latitude have flora and fauna that are not identical. This indicates that they have evolved differently; e.g Amazon forest of South America has long tailed monkeys, panthers and jaguars while similar African forests have short tailed monkeys, leopards and cheetahs.
   • Its believed that long ago and the land was one mass which later drifted apart to form the current continents. This is called the continental drift.
5. Vestigial organs.
6. Cell biology.  
   • Higher plant cells have cellulose cell walls, chloroplasts and starch showing evolution from a common ancestry.
   • -The blood pigment, haemoglobin is common in vertebrates and invertebrates.
   • -Cells of higher organisms show basic similarities in their structure and function; e.g. the presence of cell membranes and organelles such as mitochondria, ribosomes and golgi bodies.