EVOLUTION

Question 1

how did Linneus play a part in evolution

Answer 1

classified plants and animals into hierarchey system e.g. Homo sapiens, by looking at characteristics :
- Vertebrates - invertebrates = backbone or not
- Types of mammals = give birth placental / aplacental

Question 2

explain Darwin contribution to the evolution theory

Answer 2

• went to med school - later pursude natural science
• Fact of evolution was known before him
• He explained WHY it was happening

Question 3

explain Edmonstone contribution to the evolution theory

Answer 3

• indirectly contributed to Darwin’s work in evolution
• skills in taxidermy due to tasks given by enslaver (e.g. hunting)
• Teaches Darwin taxidermy while hanging out with him - proved valuable during Darwin’s research trips, e.g. HMS Beagle
• Darwin respected Edmonstone and considered him his intellectual equal

Question 4

explain the HMS Beagle research trip

Answer 4

• British royal navy vessel
• Made navigation better
• 5 year voyage – supposed to be 2
• Darwin collect samples of different specimens from places – develop a picture of the world wide distribution of variation

Question 5

explain Erasmus Darwin contribution to the evolution theory

Answer 5

• Charles’ Grandfather
• Physican + botanist
• Wrote about the idea of evolution in a book before Darwin published his book

Question 6

explain Comte de Buffon contribution to the evolution theory

Answer 6

• proposed that animals migrate and change in response to their environments
• argued that animals in the ‘New World’ were inferior to those in the ‘Old World’ (Europe, Asia, and Africa) - believed that the American environment were harsher and less favorable - lead to smaller, weaker, and less diverse animals

Question 7

explain Jean baptiste Lamarck contribution to the evolution theory

Answer 7

• wrote The Natural History of Invertebrate Animals
• believed organisms could acquire traits during their lifetime based on use and disuse and pass these traits on to their offspring e.g. giraffes stretch their necks to feed off trees – generations later their necks gradually grow

Question 8

explain Georges cuvier contribution to the evolution theory

Answer 8

• organized the animal kingdom based on anatomical and physiological characteristics
• theory of catastrophism - earths features are shaped by natural disasters which caused mass extinctions of species - after which new species would appear

Question 9

explain Charles lyell contribution to the evolution theory

Answer 9

• theory of uniformitarianism - geological processes have been occurring in the same way throughout Earth’s history
• principles pf geology book - Darwin took a copy on HMS beagle
• threat suggested Earth was much older than previously thought (around 300 million years) - though we now know it to be closer to 4.5 billion years

Question 10

explain Thomas Malthus contribution to the evolution theory

Answer 10

• Essays on the principle of population book - explored the relationship between population growth + resources (especially food)
• Malthusian catastrophe = eventually there will be not enough food to feed the population

Question 11

7 people that contributed to Darwins evolution theory

Answer 11

Edmonstone
Erasmus Darwin
Comte de Buffon
Jean baptiste Lamarck
Georges cuvier
Charles lyell
Thomas Malthus

Question 12

4 fundamental observations that Darwin made about the natural world that helped him develop the theory of evolution

Answer 12

1. Mechanism – Variability
   - individuals within a population vary in their traits e.g. morphology and behaviour
2. Mechanism – Inheritance
   - Recognises organisms inherit characteristics from parents
3. Mechanism – Offspring Numbers
   - organisms produce more offspring than can survive to adulthood
4. Mechanism – Competition
   - competition among individuals for limited resources such as food, shelter, and mates

Question 13

explain Natural selection

Answer 13

• If the ability to survive + reproduce is linked to traits that are passed down, then new traits that help organisms to have these will become more common over time
• Darwin didn’t publish books until 1859 – origin of species

Question 14

example of sexual selection

Answer 14

• Male peacocks have large, colorful tail feathers - make them more visible to predators + slow them down when flying BUT it provides a significant advantage in reproduction (indicators of good health / genetic quality)
• Asymmetry of investment - Sperm are “cheap” to produce - can produce many offspring - eggs are “expensive” - require more resources to produce and care for the offspring

Question 15

2 mechanisms by which sexual selection operates

Answer 15

Female choice
Male-male competition

Question 16

explain female choice in sexual selection

Answer 16

• females often choose mates based on specific traits that refelct the quality or fitness of a potential partner
• e.g. zebra finch - males with brighter beaks (due to a diet rich in carotenoids) are considered healthier - signal good nutrition and overall well-being - 90% of females preferred males with brighter faces

Question 17

explain male-male competition in sexual selection

Answer 17

• males compete with each other for access to females
• e.g. elephant seals - males fight for control over land territories where females gather to breed to gain exclusive reproductive access to all the females on that beach
• 90% of male elephant seals die without reproducing, while a small number of successful males are able to father 80-100 offspring
• leads to sexual dimorphism - male = 4x size of females because larger males are more successful

Question 18

example of 3 vestigial characteristics as a result of evolutionary change

Answer 18

• pythons (leftover legs) - small, vestigial leg bones - remnants from when their ancestors were four-legged reptiles - no longer serve the function of movement
• Whale pelvic bones - remnants from their ancestors who walked on land - once supported legs, but as whales adapted to a fully aquatic life, legs were no longer needed
• vestigial gene (GLO) - glucose -> vitamin C - there but does not work due to mutations (leftover from ancestors that could make their own) - has to get from diet instead - risk of developing scurvy if don’t get enough

Question 19

example of an evolutionary change achieved by remodelling in humans

Answer 19

testes
- Original position of testes = parallel to belly button
- has to migrate to normal position for better temp for sperm – leads to weakness in abdominal wall – more probable to hernea
**they come from fish testes – consequence of evolutionary history

Question 20

example of an experiment that tested an hypothesis of adaptation by natural selection

Answer 20

kestrels
- Lay just under 6 eggs per nest - is this optimal? -tested whether increasing or decreasing the number of eggs would improve the kestrels’ lifetime reproductive success
- found parents with larger clutch sizes (8 eggs) fledged more chicks (6.99 chicks) than those with average (6 eggs) or reduced (4 eggs) clutch sizes
- BUT larger clutch sizes reduced parent survival rates - only 43% of parents with enlarged clutches (8 eggs) survived
- Parents with average clutch sizes (6 eggs) had the highest lifetime reproductive success therefore is optimal
- kestrels have evolved to lay around 6 eggs per nest - balance between maximizing the number of chicks they can raise + ensuring the parents survive long enough to continue reproducing