T20 - Origin of Animals

Question 1

What is the likely common ancestor of ALL animals

Answer 1

a flagellated eukaryote that was similar to choanoflagellate protists

Question 2

fill in and explain the following relations between choanoflagellates and animals:
1. cell _ _ _ _ between choanoflagellates and sponges
2. cell _ _ _ _ with animal cells in general
3. _ _ _ sequencing

Answer 2

1. cell morphology with sponges: collar cells
2. cell morphology: similar cells between choanoflagellates and animals that are unique to them
3. DNA

Question 3

what are the advantages of multicellularity?

Answer 3

• specialization
• increased size and complexity
• longer life span
• avoiding predation

Question 4

where is the ediacaran biota?

Answer 4

south austrailia, where multicellular animals were first found (of course its in austrailia)

Question 5

why was the cambrian explosion important in animal evolution?

Answer 5

this shows the first major fossil appearance of bilaterian animals

Question 6

fill in the hypotheses behind the cambrian explosion
1. new _ _ _ _ _ relationships
2. increased _ _ _ _ in water
3. evolution of the _ _ _ _ gene

Answer 6

1. new predator-prey relationships
2. increased oxygen in water
3. evolution of the hox gene