Lecture 15

Question 1

What is evolution?

Answer 1

Change in the heritable characteristics of living organisms over successive generations.
- descent with modification through earth’s history

Question 2

What are the two competing viewpoints on life, historically?

Answer 2

• organisms are fixed, and do not change over time

- organisms change over time

Question 3

What is the Plenum?

Answer 3

fulness of the world

Question 4

What did the discovery of fossils throughout the 19th century show?

Answer 4

That strange creatures once existed that are no longer alive today

Question 5

What is transmutation?

Answer 5

An early ‘pre-evolutionary’ model that stated there were direct ancestor-descendent relationships between species.
- Essentially, living species are descendants of earlier, distinct species

Question 6

What was the discovery of the primary mechanism of evolution the world of?

Answer 6

Two English naturalists:

• Charles Robert Darwin
• Alfred Russel Wallace

Question 7

What is variability?

Answer 7

There is variation in all populations of organism

- no two members of a population are identical

Question 8

Why was the idea that individual are variable novel?

Answer 8

As early naturalists believed in ‘perfect types’

Question 9

What is heritability?

Answer 9

variation is inherited
-heritable traits are coded in DNA, with different genes carrying different alleles
(dominant; recessive)

Question 10

What do different combinations of alleles result in?

Answer 10

Different genotypes, and the physical expression of these genotypes result in a phenotype

Question 11

What are mutations?

Answer 11

New variations in inheritable traits caused by miscopied DNA. Some are harmful, some neutral, and others are beneficial.

Question 12

What is Superfecundity?

Answer 12

Organisms produce more offspring than can survive.

- reproductive excess

Question 13

What is the mechanism for how organisms change over time?

Answer 13

Natural selection, which was analogous to a artificial selection, or domestication.

Question 14

What was natural selection defined by?

Answer 14

• variability
• heritability (inc. mutations)
• super fecundity

Question 15

When will an organism have a better chance of survival?

Answer 15

If some variation gives an individual organism an advantage for survival, and if they pass that onto offspring, then there is a better chance that organism (and successive generations) will survive.

Question 16

What is natural selection?

Answer 16

Is the variable and/or differential survival and subsequent reproduction of organisms in a population, resulting in a overall change in phenotype in the descendent.

Question 17

What does natural selection happen to?

Answer 17

not individuals, but to populations

Question 18

What does natural selection NO require?

Answer 18

Does not require simple organisms evolving to be more complicated. Cannot evolve toward something, there is no ‘end goal.’

Question 19

What are homologies?

Answer 19

Shared ancestry between a pair of structures, or genes indifferent taxa. Structures adapt to different purposes as the result of descent with modification.

Question 20

What is homoplasy?

Answer 20

Characters that have evolved independently, but serve similar functions.

Question 21

What are adaptions?

Answer 21

• specialized features of animals and plants that perform one or more useful functions
• allow that organism to excel in its environment

Question 22

What is hierarchy?

Answer 22

life s a tree of relatedness with descendants branching out from common ancestry

Question 23

What are vestigial organs?

Answer 23

Traits that have lost all or most of their original function throughout evolution.
- may also retain lesser functions or develop a new, more minor function

Question 24

What are common ancestors?

Answer 24

Fossil record of groups intermediate between distinct modern groups represent common ancestors.
- new species are the modified descendants of older species

Question 25

What is an example of ‘evolutionary trends’ in groups?

Answer 25

common ancestors

Question 26

Why does the Principle of Fossil Succession work?

Answer 26

Because Earth has a single, non repeating history

Question 27

What are the five main components of evolution?

Answer 27

1) descent with modification
2) modifications occur slowly over time (generally…)
3) Populations may diverge into two or more separate lineages
4) All species share a common ancestor
5) Much of the evolutionary change present in populations is due to natural selection

Question 28

What two scales do species change on?

Answer 28

1) microevolutionary scale (changes within a species)

2) macroevolutionary scale (more large scale changes)

Question 29

What are microevolutionary and macroevolutionary changes demonstrated through the concepts of?

Answer 29

• divergence

- common ancestry