Evolution

Question 1

Fossils

Answer 1

Law of superpositions
Fossils found at shallower depths are more recent and complex (similar to modern day animals) than fossils found at deeper depths

Question 2

Biogeography

Answer 2

Study of past and present geographical distribution of organisms
Environments that are different but geographically close are more likely to be populated by related species
Animals on islands evolved from mainland migrants

Question 3

Anatomy

Answer 3

Homologous structures have similar structure but different functions
Analogous structures have different structures but similar functions
Vestigial structure is a structure that no longer serves a purpose

Question 4

Embryology

Answer 4

Studies pre birth stages
Embryos of different organisms have similar stages
Vertebrates have bony spines but also have paired bouches in the throat that became gills in fish and amphibians and ears and throat in humans
Points to a common ancestor

Question 5

DNA

Answer 5

compare DNA between organisms to see how closely related they are
Indicates DNA sequence was inherited by a common ancestor

Question 6

Mutations

Answer 6

Mutations are random changes in the DNA of an individual
Creates new genes continual supply of new genetic info
Helps with variation of genetics among organisms
A heritable mutation can affect the entire gene pool
More genetic variation - increase in diversity - increase in survival

Question 7

Types of mutations

Answer 7

Neutral - no benefit or harm
Beneficial - advantageous
Harmful - reduces reproductive success of an individual
Pseudogenes are genes that have gone through a mutation and no longer serve a purpose

Question 8

Natural selection

Answer 8

Favorable alleles become more frequent in a population
Greater chance of affected individuals surviving and reproducing
Causes change in allele frequency resulting in an evolutionary change

Question 9

Selective pressures

Answer 9

Disease
Predators
Climate conditions
Food availability

Question 10

Types of natural selection

Answer 10

Directional selection :environment favours individuals with a more extreme trait
Stabilizing selection: environment favours most common variation (middle trait)
Disruptive selection: environment favours variations at opposite extremes (opposite of stabilizing selection)
Sexual selection: favouring a trait that enhances the mating ability of an individual

Question 11

Genetic drift

Answer 11

random shifting of genetic makeup of the next generation

Question 12

Bottleneck effect

Answer 12

the loss of genetic diversity following an extreme reduction in the size of a population

Question 13

Founder effect

Answer 13

small number of individuals establish a new population

Question 14

Hardy Weinberg Principle

Answer 14

in large populations in which only random chance is at work, allele frequencies are expected to retain relatively constant from generation to generation

Question 15

Prezygotic Speciation

Answer 15

Behavioral isolation - different species use different mating cues to attract a mate
Ecological isolation - different habitats
Temporal isolation - mate at different times of the year
Mechanical isolation - morphological features make the two species incompatible

Question 16

Postzygotic Speciation

Answer 16

Genetic isolation - gametes can’t fertilize
Zygotic mortality - zygote is unable to develop properly
Hybrid inviability - hybrid either dies before birth or cannot survive to maturity
Hybrid infertility - hybrid is healthy but infertiles

Question 17

Allopatric speciation

Answer 17

population is separated geographically, no longer able to exchange genetic information, mutations are not shared between populations

Question 18

Sympatric speciation

Answer 18

individuals become genetically isolated from larger population
Example the hawthorn fly

Question 19

Patterns of evolution

Answer 19

Adaptive radiation - single species evolves into similar but distinct species, each new species fills an ecological niche, occurs when new resources become available that aren’t being used by another species
Divergent evolution - species that were once similar to an ancestral species become increasingly distinct, result of different selective pressures
Convergent evolution - similar traits arise because different species adapted to similar selective pressures, species are less genetically related, appearance becomes more similar
Co-evolution - evolutionary success closely related to another species, evolutionary arms race (counter evolution, taller trees taller giraffes), dependant species (if one goes extinct the other is likely to go extinct.

Question 20

Aristotle era

Answer 20

believed that the earth and all living things were immutable

Question 21

Buffon

Answer 21

believed the earth was 6000 years old, and that organisms have been created perfect but still could have changed over time

Question 22

Erasmus Darwin

Answer 22

evolution occurs in living things and humans. All life evolved from single source.

Question 23

Lamark (the big boy)

Answer 23

PRINCIPLE 1: use and disuse ; body parts that are not use would disappear, body parts that were used became stronger
PRINCIPLE 2: inheritance of acquired characteristics
Individuals pass onto their offspring the characteristics they acquired during their lives
OVERALL: he believed that species evolve over long times, that the traits are acquired through use and disuse, that species evolve in response to their environments, and that changes are passed from generation to generation.

Question 24

Cuvier

Answer 24

identified that fossils at higher levels were more complex than those at lower levels. Believed in catastrophism: global catastrophes caused widespread extinction of species

Question 25

Lyell

Answer 25

believed in uniformation (basically catastrophism but slower), global change is slow and gradual

Question 26

Malthus

Answer 26

proposed that competition was a big ol thing

Question 27

CHARLES DARWIN (THE BIG DADDY)

Answer 27

Believed in natural selection (u know what it is but basically that the environment favors the reproductive success of certain individuals with advantageous traits over others. Population changes as advantageous traits become more common)
His four main reasons for evolution were:
- organisms compete for resources
- individuals of a population vary extensively, much of this variation is heritable
- some characteristics are more advantageous than others
- processes of change are slow and gradual