1. Evidence for Evolution

Question 1

What is evolution?

Answer 1

1. Change over time
2. Change can be phenotypic or genotypic, which includes microevolution
3. Evolutionary facts are explained by evolutionary theory in the sense of a scientific theory (Futuyma, 2009).
4. The mechanisms are debated as it is hard to see them.
5. Random events have led to the “ordered complexity” we see, and its hard to understand how this started and how it can work statistically (Barton et al., 2007).
6. Each structure only needs one reason to have evolved in a particular way, and seemingly useless traits may be side-effects or others or hold indirect benefits (Barton et al., 2007).

Question 2

Describe an example of when evolution has been observed over the last 100 years.

Answer 2

1. Floridian Soapberry bugs live on balloon vine fruit plants, which have thick pod walls.
2. Soapberry bugs have a large proboscis, which can penetrate the pod walls to obtain seeds
3. The flat-podded Golden Rain Tree, of the same genus as the balloon vine, was introduced.
4. Soapberry bugs were able to move to this as a new host plant, and evolved a shorter proboscis because the Golden Rain Tree has thinner pod walls.

Question 3

What requirements are needed for us to see evolution in real time, and what types of organisms may fulfill these?

Answer 3

1. Fast generation time
2. Large population
3. Microbes
4. Viruses
5. Some marine organisms
6. Insects

Question 4

Describe an example of when we have seen the evolution of microbes.

Answer 4

1. We have sequenced a protein coding region of HIV from different patients.
2. Diversity evolves even within one human patient.
3. New variants can develop.
4. The same changes have been documented on several occasions.
5. These changes are the result of parallel substitutions, suggesting the virus is adapting to human hosts.
6. Some evidence of adaptation to become resistant to antivirals (Barton et al., 2007).

Question 5

What is the significance of anatomically shared features in the theory of evolution? Give examples.

Answer 5

1. They suggest evolution must be true
2. Bat and bird wings are analogous
3. Skeletal forelimbs of bats and birds are homologous

Question 6

How does embryology provide evidence for evolution?

Answer 6

1. Organisms share many characteristics during early development.
2. There is a shared molecular basis for the morphological similarities shown during development.
3. This process is gene based and a similar pattern is found across species.
4. Mammal embryos display features from other animal types eg. amphibian circulatory system, which then disappear before birth (Coyne, 2009).

Question 7

How do biochemical process suggest evolution from a common ancestor?

Answer 7

1. Almost all organisms use the same system of three based per amino acid/codon.
2. This is frozen, as any changes would make functioning of animals impossible.
3. Molecular functions are widely conserved eg. all amino acids are L-amino acids when making proteins, not the D-amino acid stereoisomer (Barton et al., 2007).
4. Genes have counterparts in other organisms that have similar sequences.

Question 8

How does the fossil record suggest evolution is true?

Answer 8

1. It shows gradual change
2. Evolution is not static, for example the gradual change in the number of ribs trilobites have.
3. The fossil record also shows intermediate forms that have been predicted by scientists eg. Tiktaalik roseae

Question 9

It has been said that the imperfect anatomy of some creatures suggests that they must have evolved, as this would not make sense as a design. Give some examples of imperfect anatomy.

Answer 9

1. The left recurrent laryngeal nerve goes down and around aorta and back up to voice box, making longer than is necessary (Coyne, 2009).
2. Mammals have evolved from fish, which have branchial arches with nerves and a blood supply (Coyne, 2009).
3. The pairing of these is regulated by development, and so remains in some animals (Coyne, 2009).
4. The left recurrent laryngeal nerve was paired with an artery that has moved downwards, and so has moved downwards too (Coyne, 2009).
5. Snakes and whales have unnecessary pelvic bones (Barton et al., 2007).
6. Blind cave fish have non-functioning eyes (Barton et al., 2007).

Question 10

How does species distribution support evolution?

Answer 10

1. Closely related species are often separated by oceans.
2. This is caused by moving landmasses
3. Convergent evolution can result in a similar yet unrelated species that mirror each other globally ie. take each other’s place in similar habitats (Barton et al., 2007).