Evolution

Question 1

What is evolution?

Answer 1

The process of organisms adapting over time due to environment, competition or mutation that leans towards phenotypes best adapted for survival so the genotypes can be passed on to successive generations (survival of the fittest)

Question 2

What are the 4 main routes of evolution?

Answer 2

Natural selection
Common ancestor theory
Speciation
Extinction

Question 3

How does extinction lead to evolution?

Answer 3

• reduces diversity
• can lead to bottle-necking
• threats lead species to select away from vulnerable phenotypes
• New stressors

Question 4

What is the common ancestor theory?

Answer 4

Darwin’s theory that states different species of living organisms can ultimately be traced to a single common ancestor

In theory it suggests all forms of life can be traced back to a single universal common ancestor

Question 5

Which two theories make up Darwin’s theory of evolution?

Answer 5

Common ancestor theory

Natural selection

Question 6

How does the common ancestor theory lead to evolution?

Answer 6

Over time speciation has occurred from one single universal ancestor

Question 7

Name 3 pieces of evidence for the common ancestor theory

Answer 7

• Common biochemistry - DNA and RNA
• common genetic code - amino acid bases always code for the same proteins (in plants, animals and bacteria)
• Selectively neutral similarities NOT as a result of convergent evolution
• Use of ATP
• Phylogenetic trees - similar DNA, morphology, embryology

Question 8

What is one main factor opposing the common ancestor theory?

Answer 8

Convergent evolution

• it is the environment causing similarities NOT a common ancestor’s DNA etc

Question 9

Name 3 types of speciation

Answer 9

Allopatric
Sympatric
Artificial
(Also accept Peripatric and Parapatric)

Question 10

What is allopatric speciation?

Answer 10

where the two populations are physically isolated

Question 11

What is sympatric speciation?

Answer 11

when two populations are reproductively isolated in the same environment

Question 12

What is artificial speciation

Answer 12

the creation of new species by people

Question 13

Give an example of artificial speciation

Answer 13

Domestic sheep - interbreed two species to create a hybrid

Question 14

What is peripatric speciation

Answer 14

When small groups of individuals break off from the larger group and form a new species

Question 15

What is parapatric speciation

Answer 15

when a species is spread out over a large geographic area

Question 16

Name 5 factors that can cause isolation

Answer 16

Geographic
Temporal - climate may cause different spawning times
Behaviour - mating calls may be altered (causes ‘accents’)
Mechanical - structural differences
Hybrid sterility - mules, ligers

Question 17

What is extinction

Answer 17

the end of an organism/ group of organisms (taxon) – normally a species

Question 18

How may sympatric speciation occur?

Answer 18

• changes in temps may cause different spawning times (frogs)
• mating calls may differ (accents)
• hormonal changes, pheromones

Question 19

How may allopatric speciation occur?

Answer 19

Habitat fragmentation:

• Earthaquakes/ natural disasters
• hedges cut
• road built
• landscape development

Question 20

What is adaptive radiation?

Answer 20

The divergence of a single group (or species) into a series of distinct but related groups.
- i.e: Darwin’s finches

Question 21

Name an example of adaptive radiation

Answer 21

Darwin’s finches - each finch was adapted to survive in its specific niche

Question 22

what does ecophysiology mean?

Answer 22

• branch of physiology that deals with the physiological processes of organisms with respect to their environment

Question 23

Name 3 ways ecophysiology of an animal may change

Answer 23

• Range shifting - moving to areas of different temps, water availability etc
• Morphological changes - i.e: coat colour, body mass
• Breeding changes
• Behavioural changes - nocturnal activity in Arabian oryx; eating different diets

Question 24

What are 3 conditions that make animals better suited to adapt to climate change?

Answer 24

Large populations (good gene flow)
Genetic Diversity 
Short generations (can quickly adapt to stressors)
Generalist species (not specialists)
Only having one stressor at a time