origin of life 25

Question 1

Homeotic genes (Hox genes)

Answer 1

control placement and spatial organization of body parts
-Changes can result in new features
or movement of existing features
resulting in a new function

Question 2

Heterochony

Answer 2

changes in the rate or timing of development

-Structures of organism can change due to speed at which development occurs or when it occurs.

Question 3

Paedomorphosis

Answer 3

retention of juvenile features in adult

Question 4

why is Evolution not goal oriented?

Answer 4

1. it does not move toward a specific end.
2. it builds upon existing features.
3. it is the result of ongoing interactions between the organism and its environment.
4. Evolution doesn’t necessarily produce the best solution it just produces a better solution.
5. Extinction allows evolution the roll of the dice once again — It allows the opportunity for better solutions.

Question 5

Consequences of joining continents:

Answer 5

●Loss of habitats along coastline
●Brings species together that
were separated – competition
●More extreme interior climate
●Opens new niches
       Leads to adaptive radiations

Question 6

Consequences of separating continents:

Answer 6

●Creates new habitats
●Isolates organisms
●Opens new niches
Leads to adaptive radiations

Question 7

Continental Drift

Answer 7

Movement of continental plates due to convection currents of hot magma

Question 8

Results of continental drift:

Answer 8

●Formation of new environments
●Climatic changes
- change in latitude of continents
- shifting ocean currents

Question 9

Extinction Result in:

Answer 9

●Change in evolutionary course (extinct animals are gone)
●Loss of accumulated adaptations – that natural selection cannot work on
●5-10 million years to re-establish diversity

Question 10

Adaptive radiations after extinctions

Answer 10

●Permian – adaptive radiation  age of reptiles

●Cretaceous – adaptive radiation  age of mammals

Question 11

Mass extinctions correspond to

Answer 11

movement of continents