5.1 Evidence for Evolution

Question 1

Fossil Record

Answer 1

A fossil is the preserved remain or trace of a past organism
- The totality of all fossils is called the fossil record

Law of Fossil Succession:
The fossil record shows that changes have occurred in organism and these changes have occurred in a consistent sequence of development (the law of fossil succession)
Example: Ferns always appear before flowering plants

Transitional Fossils:
Transitional fossils represent intermediary forms within the evolution of a genus and demonstrate species connections.
Example: The archaeopteryx links the evolution of birds (wings and feathers) to dinosaurs (jaws and claws).

Question 2

Selective Breedingh

Answer 2

Is when you breed animals with desired characteristics (it is a form of artificial selection).

Examples of this Draft horses (power and Race horses (speed)
Dog breeds
Cows with larger pelvis.

Question 3

Molecular evidence

Answer 3

Closely relates species share a greater degree of similarity in their DNA and protein sequence (due to a common ancestor). If a particular gene has a stable mutation rate, the time of evolutionary divergence can be estimated (molecular clock)

Question 4

Vestigial Strictures

Answer 4

Some species show presence of functionless or reduced remnants of organs that were once present in ancestors. ie. Whales (pelvic bone (ancestors were terrestrial).

Question 5

Comparative anatomy

Answer 5

Homologous Structures are anatomical features that share a common basic structure despite having distinct functions.

Rapid diversification of an anatomical feature is a result of adaptive radiation (organisms adapt to different niches)

Closely related species demonstrate greater homology.

Pentadactyl limb- Human arm, horse leg, whale arm, turtle arm, frog arm, bird arm.

Question 6

Comparative Embryology

Answer 6

Comparative embryonic development in animals demonstrates similarities that suggest a common evolutionary pathway.

All terrestrial animals have non-functioning gills slits.
Many vertebrates have a primitive tail in early stages.

Question 7

Biogeography

Answer 7

Biogeography is the distribution of species across an area .

Related species will usually be found in close proximity.

Monotremes are exclusive to Australia/ New Guinea.

Exceptions may be explained via continental drift.