Unit 3: Evolution

Question 1

What is EVOUTION?

Answer 1

Change in the heritable characteristics of biological populations over successive generations.

Question 2

What did DARWIN theorize?

Answer 2

• species can change over time
• new species come from pre-existing species
• all species share a common ancestor

Question 3

NATURAL vs ARTIFICIAL SELECTION

Answer 3

Natural selection occurs as a result of an organism adapting to its surroundings.
Artificial selection is selective breeding imposed by an external entity to enhance the frequency of desirable features

Question 4

What is ADAPTATION?

Answer 4

The ability of an organism to adapt to evolutionary pressures

Question 5

ALLOPATRIC vs SYMPATRIC

Answer 5

Prezygotic reproductive barriers
ALLOPATRIC: in different areas → separated by geography
SYMPATRIC: in the same areas but differ in habitats, habits, etc. (e.g. gathering food differently on the same tree) → will never meet

Question 6

What is MUTATION?

Answer 6

a change in the DNA sequence of an organism

Question 7

What is a FOSSIL/FOSSILIZATION?

Answer 7

Preserved remains, or traces of remains, of ancient organisms
The process of turning a plant/animal that used to exist into a fossil

Question 8

What is GRADUALISM?

Answer 8

The evolutionary process in which species experience changes in characteristics slowly and incrementally

Question 9

What is PUNCTUATED EQUILIBRIUM?

Answer 9

Short periods of rapid evolution, followed by stasis (a point of little change/staying the same)

Question 10

What is SPECIATION?

Answer 10

The process by which new distinct species form (what happens as a result of evolution)

Question 11

What is SELECTIVE ADVANTAGE?

Answer 11

Any characteristic or trait that gives an organism or a genotype greater chances of surviving and reproducing than the available alternatives
For example, lions with phenotypes that are fitter and faster are more likely to be able to catch prey, survive and reproduce
Their phenotype is said to provide them with a selective advantage

Question 12

What is HOMOLOGOUS STRUCTURE?

Answer 12

Same origin, different function

Different species share similar physical features due to their connection to a common evolutionary ancestor. The features serve different purposes.
E.g.
Humans and cats have the same bone structure, however serve different functions.

Question 13

What is ANALOGOUS STRUCTURE?

Answer 13

Different origins, same function

The physical similarities evolved independently in the different species, likely due to living in similar environments or experiencing similar selective pressures (needs)
*This is called convergent evolution-coming together
E.g. bats and birds have wings that have the same function but are completely unrelated species. This is shown by the differences in bones.

Question 14

MICROEVOLUTION

Answer 14

• Changes in allele frequencies over time in a population
• This change happens over a relatively short amount of time

E.g. a population may have 70% green and 30% blue alleles, but the next generation might have 50% greens and 50% blue alleles - there is a change in allele frequencies, therefore evolution has occurred

E.g. different types of dogs

Question 15

MACROEVOLUTION

Answer 15

• Evolution above the species level. Macroevolution is the same as microevolution, but includes the origin of new species.
• Longer periods of time

E.g. Apes vs Homo sapiens

Question 16

What is VESTIGIAL STRUCTURE?

Answer 16

• Leftover/no longer useful
• Structures that have lost their ancestral function and are often reduced in size.

E.g. the tailbone in humans evolved from the tail that is present in the embryo, the same tail in whales, dogs, cats, etc.)

Question 17

What are SPECIATION MECHANISMS?

Answer 17

Allopatric
Species are in different areas → separated by geography

Sympatric
Species are in the same areas but differ in habitats, habits, etc. (e.g. gathering food differently)
E.g. Initially, the apple maggot flies lay their eggs on hawthorn fruit Then, a distinct form of maggot fly emerged that lay eggs on apples only. Now, two distinct groups of apple maggots are found: one laying eggs on apples and the other laying eggs on hawthorns.

Parapatric
Multiple versions of species evolve from one species, but the “extremes” of the species can no longer mate with each other. (and are thus considered different species) if the Hybrid zones are removed
E.g. a skink from Quebec can’t mate with a skink in BC if the hybrid zone (the rest of Canada - their contact point) is removed

Question 18

What is MIMICRY?

Answer 18

The superficial resemblance of two or more organisms that are not closely related taxonomically. This resemblance confers an advantage—such as protection from predation

e.g. stick insect looking like a stick