Question

Cartilaginous fishes Ray-finned fishes Lobe-finned fishes - Amphibians X Human Cartilaginous fishes Ray-finned fishes Lobe-finned fishes Amphibians - Human Orca Birds and reptiles Cartilaginous fishes Ray-finned fishes Lobe-finned fishes - Amphibians Human Orca Birds and reptiles Orca - Birds and reptiles Cartilaginous fishes Ray-finned fishes Cartilaginous fishes Ray-finned fishes Lobe-finned fishes Amphibians - Human Cartilaginous fishes Ray-finned fishes Lobe-finned fishes Amphibians - Human Lobe-finned fishes Amphibians X Human Orca Orca - Birds and reptiles Orca Birds and reptiles Birds and reptiles X E Question 1 (1 point) ✓ Saved Questions 1-5 use the phylogeny shown above, where the black rectangle indicates "evolutionary gain of fins" and the black cross means "evolutionary loss of fins”. In
just questions 2-5

Answer 1

2. Answer to the question is E

Of the given animals, humans, amphibians, birds and reptiles do not have fins. Considering the given situation of rectangle and crosses, we can infer that A,B,C,D,F are fulfilling this condition. However, phylogeny E presents us with a situation indicating presence of fins in both humans and orca(whale) which is contrary to contemporary observations.

3. Answer to the question is A

In A, orca and fishes have the same ancestral origin of fins thus making it a homology.

4. Answer to the question is D

Parsimonious implies a hypothesis which has least evolutionary changes. It tends to minimize unnecessary complicated changes. In phylogeny D, there are a total of 3 evolutionary changes which is the least of all the given phylogeny and hence is the most parsimonious.

5. Answer to the question is (b) and (d).

The most parsimonious evolutionary history is represented by phylogeny D. It shows homoplasy because the fishes and orca do not have the same ancestral origin for fins. It also exhibits evolutionary reversal because the presence of fins in orca reverted back to the common ancestor form. It is not convergent evolution because the fins do not evolve independently in each lineage, rather it is present only in one lineage. It doesn't present homology because they do not share the common ancestor for presence of fins.

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