Evidence of Evolution Fossils Geography Comparative Embryology Comparative

Evidence of Evolution • Fossils • Geography • Comparative Embryology • Comparative anatomy • Comparative biochemistry

1. Fossils • The remains or tracks of an organism that died a long time ago that has been preserved by a natural process. • The relative age of a fossil can • be determined by knowing the age of the rock layer • (Higher rock layer – closer to earth’s surface ‘younger’ fossil than found in lower rock layer)

No dinosaur in the world compares to SUE—the largest, most complete, and best preserved Tyrannosaurus rex ever discovered. http: //www. fieldmuseum. org/sue/#sues-discovery

Trilobite fossils

A baby mammoth has been uncovered in the permafrost of north-west Siberia

Lyuba

Archeopteryx – Bird or reptile? - feathers (birds) - teeth and fingers (reptiles)

The fossil turtle Odontochelys semitestacea

2. Geography • Species could adapt to different evironments – for example Darwin’s finches and the Galapagos tortoises.

Darwin’s Famous Finches

Darwin noticed they were all similar, but also slightly different. Each was adapted to a different “niche” for the island they lived on. They were all shared a common ancestor from the South American mainland.

Saddle back tortoise – long neck to reach tall plants. Domed tortoise has short neck and legs and live in areas with low vegetation like mosses.

3. Comparative Embryology 2 Species that show similar traits during embryological development likely have a common ancestor. For example vertebrate embryos show structures such as a tail, yolk sac and gill slits.

dolphin human

4. Comparative Anatomy: Comparing body parts of different species. 4. 1) Homologous structures: Similar body parts that originated in a common ancestor, but now perform different functions. For example: Wing of a bat, Flipper of a whale, Front leg of a cat, Human hand.

Internal structures are similar and indicate evolutionary relationships between these animals. These limbs are modifications of an original forelimb found in an early shared ancestor.

4. 2 Analogous structures: • Structures that perform the same function, but are different in structure and not similar in origin. • For example: Insect wing and Bird wing.

4. 3 Vestigial structures: • Remnants of organs or structures that once had a function in an early ancestor, but lost their function over time.

5. Comparative Biochemistry/ Molecular evidence: • Comparison of the nucleotide sequence in DNA and RNA of different species. • Comparison of the amino acid sequence in proteins. • More similar the sequences = more closer related the species are.