Week 4

Question 1

Describe the features of multicellular organisms:

Answer 1

• Differentiation/specialisation of tissues
• Full sexual reproduction
• Metamerism
• Symmetries
• Body cavities
• Cephalization and encephalization

Question 2

What’s metamerism?

Answer 2

Process of segmentation in which a body have many simple copies and they differentiate and specialise in different tasks.

Question 3

What are the four type of symmetry?

Answer 3

• Radial
• Bilateral
• Modified radial
• Spherical

Question 4

Why is colagen important?

Answer 4

Colagen it’s a connective tissue and glue many different cells together. Furthermore it’s one of the unifyng features of animals.

Question 5

What are stromatolites?

Answer 5

Layered accretionary structure, comunities of cells formed from binded sediments trapped in biofilms and reinforced with CaCO3.

Question 6

What are the characteristics of ediacaran biota?

Answer 6

• Soft body (No shell or mineralized skeleton or armor)
• No eyes
• No evidence of predation
• No symmetry
• No supporting development
• They were only marine/Acquatic.

Question 7

What might be the cause of extinction of ediacaran fauna?

Answer 7

The beginning of predation

Question 8

What are the features of cambrian fauna?

Answer 8

• Skeletal structures, hard bones and teeth.
• Appearence of predation
• Metamerism

Question 9

Why there was a quick differentiation of animals?

Answer 9

• Predation could have driven evolution
• Rise of O2
• Maybe snowball earth suppressed precambrian life
• Genetic changes: diversification of homeotic genes.

Question 10

Why there was the rise of O2?

Answer 10

Because phytoplankton increased

Question 11

What are homeotic genes?

Answer 11

Any multicellular organism developed as an animal because these genes were inherited to create symmetrical body and its structures.

Question 12

Why is the rise of O2 so important?

Answer 12

Because it allowed organism to achieve increased size (important for predation) and metabolic rates were speed up.

Question 13

Who was the ancestor of chordates?

Answer 13

Pikaia

Question 14

What’s adaptive radiation?

Answer 14

It’s evolutionary divergence of members of a single phyletic line into a series of rather different niches or adaptive zones.

Question 15

Describe the process of adaptive radiation:

Answer 15

After a mass extinction event niche spaces are opne and orgnanism fiil into these space and diversifiy to fill the gaps.

Question 16

Define the 3 conditions of adaptive radiation:

Answer 16

1-Occur at edges of a species
2-It’s facilitated by the absence of competitors.
3-May involve general adapatations.

Question 17

What’s cambrian explosion?

Answer 17

Rapid diversification of life after a mass extinction of ediacaran biota.