EVOLUTION

Question 1

what are the 6 classifications of locomotion

Answer 1

1. scansorial = adapted for climbing (ground + trees)
2. arboreal = tree-living
3. terrestrial - ground
4. ambulatory = not specialised (slow)
5. cursorial - specialised for speed
6. saltatorial = bounding/hopping

Question 2

what are adaptations of climbers (scansorial + arboreal)

Answer 2

• propulsion on discontinuos + 3D substrate
• avoiding falling (grasping mechanisms)
• small and light
• balancing mechanisms - tail - heavy

Question 3

what are some grasping mechanisms

Answer 3

flexor muscles, opposable thumbs, long digits, prehensile tail

Question 4

what are some propulsion mechanisms

Answer 4

• flexed limbs with a low centre of gravity
• leaping and springing -> long and skender legs
• flexible spine
• Brachiation - arm swinging (long and thin arms)

Question 5

what is gait

Answer 5

how limbs move e.g. walk vs run

Question 6

features of cursorial animals

Answer 6

• travel far and fast
• speed and endurance
• acceleration and manoeuvrability
• increased speed = reduced manoeuvrability

Question 7

what is bipedalism and advantages

Answer 7

movement via two rear limbs -> centre of mass is positioned over lower limbs
ADS:
- efficient
- raises head = wider range of vision
- free hands for tool use
- reduces protrusions away from body -> body weight distributed evenly

Question 8

Bipedal adaptations for efficiency

Answer 8

1. stride length requires leg springs and long legs
2. energy storage - long calcanea tendon, plantar arch
3. skeletal strength - stress reduced by extended (shock absorption)
4. stabilisation - large glutes, neck muscles

Question 9

what is a phenotype

Answer 9

visible characteristics expressed

Question 10

what is a genotype

Answer 10

code for characteristics

Question 11

what are the 5 main ideas of darwinism

Answer 11

1. perpetual change
2. common descent
3. multiplication of species
4. gradualism
5. natural selection

Question 12

explain perpetual change

Answer 12

• varying forms of organisms undergo measurable change over generations and time
• documented via fossil record
• changes may be in response to environmental changes

Question 13

explain common descent

Answer 13

• all forms of life descend from a common form of life through branching of lineages

Question 14

define phylogeny and how it is useful

Answer 14

• pattern of relatedness between different species
• basis for taxonomic classifications

Question 15

explain multiplication of species

Answer 15

• origin of organic diversity
• species multiply by splitting into daughter species or by ‘budding’ (establishment of geographically isolated founder population that evolve into new species)

Question 16

Explain gradualism

Answer 16

slow gradual changes over time

Question 17

Explain natural selection

Answer 17

DEF: theory that organisms best suited to survive will live to reproduce, passing on favourable characteristics to the next generation
- surviving individuals pass on well adapted inheritable characteristics
- caused by competition for reproduction and survival

Question 18

define evolution

Answer 18

• when heritable differences in a population become more common or rare over generations

Question 19

define adaptation

Answer 19

An inherited trait that promotes survival and reproduction for a species - becoming better suited to an environment

Question 20

what are the principals of natural selection

Answer 20

• variation must exist in population
• traits are inheritable
• more offspring produced than survive
• offspring of parents with advantageous trait are more likely to ave trait too = differential reproductive fitness

Question 21

define species

Answer 21

a group of organisms capable of reproducing to produce fertile offspring

Question 22

define random genetic drift

Answer 22

random fluctuations of allele frequencies within populations across generations caused by random chance events

Question 23

define adaptive radiation

Answer 23

environment changes drastically causing many variations of one common ancestor e.g. volcano

Question 24

define sexual selection

Answer 24

the selection of traits that are advantageous for gaining a mate but aren’t necessarily advantageous for survival

Question 25

define artificial selection

Answer 25

the selective breeding of organisms by humans to enhance specific traits

Question 26

convergent vs divergent evolution

Answer 26

convergent - organsims evolving to a common environments similarly without a common ancestor
divergent - common ancestor but evolve differently in different environments

Question 27

what is co-evolution

Answer 27

frequency of many genes of a species changing in freq at same time (fast)