Chapter 22 Darwin and Descent Modification

Question 1

True or false?
Evolutionary is a theory about the origin of life

Answer 1

False.
evolution deals with how life changed after its origin

Question 2

True or false?
Evolutionary is like a climb up a ladder of progress; organisms are always getting better

Answer 2

False.
better (i.e., reproductive fitness) is linked to the environment, not to progress

Question 3

True or false?
Evolution means that life changes randomly

Answer 3

Partially false.
indeed random mutations are the ultimate source of genetic variation… but the current environmental conditions limit evolutionary change to only those variations (a.k.a. inheritable variations) that improve population fitness.

Question 4

True or False?
Natural selection involves organisms trying to adapt

Answer 4

False.
as this is Lamarck’s view

Question 5

What is Lamarck’s evolutionary view? Why rejected? (2)

Answer 5

“Inheritance of acquired characteristics”
- traits passed on through genes not acquired characteristics.
“Use and disuse”
- not fast like lamark thinks VERY slow process (time scale). not every change in use leads to change in structure (functionality)

Question 6

True or False?
Natural selection gives organisms what they need

Answer 6

False.
Natural selection has no intentions nor senses; natural selection cannot “sense” what an organism needs

Question 7

True or False?
Evolution is just a theory

Answer 7

True.
What does theory mean tho?

Question 8

Wat is the central premise evolutionary theory?

Answer 8

• life has existed for billions of years and has changed over time
• how has it changed  with descent through modification by natural selection

Question 9

What lead to Darwins proposal?

Answer 9

Historical roots.

Question 10

What is descent with modification by natural selection?

Answer 10

In a limited environment, individuals with traits better suited to their habitat are more likely to survive and reproduce.

Question 11

Why is natural selection an ongoing process?

Answer 11

Because Earth and environments constantly change, traits that were once beneficial may no longer be, forcing species to adapt or go extinct.

Question 12

How can new species form?

Answer 12

If adaptation leads to reproductive isolation, it can result in the formation of a new species.

Question 13

Lamark vs Darwin giraffe neck?

Answer 13

Lamark: acquired characteristics through generations
Darwin: enivronmental stress, contraint and behavior.

Question 14

What are Darwins lines of evidence?

Answer 14

1. Direct observation
2. Homology and vestigial structures
3. Fossil record
4. Biogeography

Question 15

What is whales early ancestor?

Answer 15

Pakicetus(50Ma) described as early ancestor to modern whales

Question 16

Species that transitioned from water to land?

Answer 16

Tiktaalik (375 Ma)

Question 17

Explain biogeography.

Answer 17

distribution of species/ ecosystems in geographic space and through geological time.