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Biology 3&4 > U4 AOS1 SAC Revision > Flashcards

U4 AOS1 SAC Revision Flashcards

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1
Q

What is a selection pressure?

A

A condition/factor which influences and affects allele frequencies within a population

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2
Q

What other thing along with selection pressures are described as being the “driving force of evolution”?

A

Mutations

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3
Q

What are the 3 main categories of selection pressures?

A

Abiotic which includes aspects of the physical environment
Influence from another species like parasitism and predation
Population pressure which includes competition between members

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4
Q

What is the definition of Natural Selection?

A

A mechanism of evolution

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5
Q

What are the 6 main factors of Natural Selection?

REMEMBER MNEMONIC

A

1) Variation must exist within the population
2) Overcrowding exists, meaning not all individuals can survive
3) Phenotypes that suit their environment are ‘selected for’
4) Individuals with these phenotypes are more likely to survive
5) They can then reproduce
6) Passing their alleles onto the next generation

Very Old Species Sometimes Remain Idiotic

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6
Q

What is Gene Flow?

A

The movement of individuals (migration) of the same species from one population to another

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7
Q

What happens when Gene Flow stops?

A

A species is considered to be isolated, which leads to speciation

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8
Q

What is Genetic Drift?

A

A change in allele frequency within a gene pool over time, which occurs randomly or by chance

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9
Q

Where is Genetic Drift more likely to occur?

A

In smaller populations, as there is less less gene flow

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10
Q

What are 2 processes considered to be types of Genetic Drift?

A

1) Bottleneck Effect

2) Founder Effect

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11
Q

What is the Bottleneck Effect?

A

A severe reduction in genetic diversity that occurs due to a catastrophe like a natural disaster, or by human activity which may result in a change in allele frequency

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12
Q

How do Bottleneck Effects affect allele frequencies/variation?

A

Smaller populations mean that there are less individuals, which may result in inbreeding. This therefore reduces variation within the population

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13
Q

What is the Founder Effect?

A

Occurs when a small group of individuals from a larger population move to a new population starting a new gene pool

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14
Q

How does the Founder Effect affect allele frequencies/ variation

A

It results in a smaller population being produced which leads to inbreeding which reduces variation, and new selection pressures can then drive natural selection to occur.

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15
Q

What are the 4 main ways that Variation is produced?

A

1) Random mating
2) Independent Assortment of chromosomes during Meiosis
3) Recombination of chromosomes during fusion of Gametes
4) Mutations

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16
Q

What is Continuous Variation?

A

Type of variation where the variation of a gene has an infinite amount of possibilities

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17
Q

What is Discontinuous Variation?

A

Type of variation where the variation of a gene has a select/limited amount of possibilities

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18
Q

What is Allopatric Speciation?

A

The phenomenon whereby a new species is formed due to geographical isolation of two populations of the same species

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19
Q

What is Speciation generally?

A

The evolution of a new species from an ancestral species

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20
Q

What is Selective Breeding?

A

Method of breeding where animals with a particular phenotype that is desired to the breeder are allowed to breed, which leads to an increase in frequency of the desired trait

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21
Q

What is a key difference between random mating and selective mating?

A

Selective breeding involves humans choosing organisms with desired traits and breeding them, while random mating involves individuals all having an equal chance of mating

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22
Q

What are 3 Negatives of Selective Breeding?

A

1) Reduces genetic variation which can lead to a reduction in resistance to environmental change
2) Reduces biodiversity of domesticated species
3) Can increase the frequency of genetic abnormalities

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23
Q

What are Fossils?

A

Fossils are preserved remains, impressions or traces of organisms found in rock or mineral deposists

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24
Q

What is the Fossil Record?

A

The total number of all fossils that have been discovered

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25
Q

How does Fossilisation occur, and where is it more likely to occur?

A

Fossilisation occurs when an organism is covered in sediment, as this reduces the decay due to the lack of oxygen and decomposers. This is more likely to occur in aquatic environments due to the constant movement of sediment.

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26
Q

What are the 4 main types of Fossils?

A

1) Impression Fossils
2) Mineralised Fossils
3) Trace Fossils
4) Mummified Organisms

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27
Q

What are the 2 main techniques used in relative dating of fossils?

A

1) Principle of Superposition

2) Principle of Correlation

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28
Q

What is the principle of superposition?

A

This principle is used to distinguish the relative age of rocks, and states that the oldest stratum is at the bottom, with younger layers lying above it.

29
Q

What is the principle of correlation?

A

This principle is too used to distinguish the relative age of rocks, but it is based on identifying the presence of index fossils, which are fossils that are known to be present all over the world which means that the all exist in the same stratum of rock.

30
Q

What are the 3 different techniques of Absolute Dating?

A

1) Carbon-14 Dating
2) Potassium-Argon Dating
3) Electron Spin Resonance

31
Q

What is Carbon-14 dating used to date?

A

Organic remains up to 60 000 years old

32
Q

What is Potassium-Argon dating used to date?

A

Igneous rocks containing K-bearing minerals that are 0.5 Myr and older

33
Q

What is the Electron Spin Resonance used to date?

A

Any material that is between 50 000 to 500 000 years old

34
Q

What is Divergent Evolution?

A

Type of evolution that occurs when one ancestral species gives rise to several new species over time

35
Q

What structures are organisms that evolved via Divergent evolution more likely to have?

A

Homologous Structures as they have evolved from a common ancestor

36
Q

What is Convergent Evolution?

A

Type of evolution which occurs when two species, which do not share a recent common ancestor, independently develop similar features due to similar selection pressures

37
Q

What structures are organisms that evolved via Convergent evolution more likely to have?

A

Analogous structure as they have evolved structures in a similar way with a similar function

38
Q

How is the ABSOLUTE age of a rock expressed?

A

Expressed as exact units of time

39
Q

How is the RELATIVE age of a rock expressed?

A

Expressed as being simply younger, older or the same age as other rock strata

40
Q

What are 3 different types of substitution in DNA sequences?

A

1) Conservative
2) Semi-conservative
3) Non-conservative

41
Q

Why is looking at Amino Acid sequences useful in determining relatedness between species?

A

The accumulation of mutations in DNA results in different amino acid sequences of proteins

42
Q

What is another name for Divergent Evolution?

A

Adaptive Radiation

43
Q

What are the 5 ideal circumstances for Fossilisation to occur?

A

1) Rapid covering of organism in sediment
2) Protection from the elements and scavengers/decomposers
3) Slower rate of decomposition (low oxygen levels, alkaline or cold environment)
4) Further layers of sediment
5) Little disturbance of burial site

44
Q

Explain the ‘Molecular Clock’ technique

A

The Molecular clock is a process where mtDNA sequences of different species are compared, and the amount of differences in the base sequences are recorded. The number of changes can be used to calculate the relative time that has passed since the two diverged from a common ancestral species.

45
Q

What is Conservative Substitution?

A

Occurs when an amino acid is replaced by one with similar biochemical properties and shape, which has little to no affect on the protein

46
Q

What is Semi-Conservative Substitution?

A

Occurs when an amino acid is replaced by another which has a similar shape but different biochemical properties, meaning that there can be possible changes to the shape or function of the protein produced.

47
Q

What is Non-Conservative Substitution?

A

Occurs when an amino acid is replaced by a very different one, which has major changes in the function and shape of the protein produced.

48
Q

What are 3 limitations of the ‘Molecular Clock’ technique?

A

1) Assumes the rate of genetic mutations is constant, when it can actually be increased or decreased by many factors
2) Different sections of DNA mutate more frequently then others (different speeds to their molecular clocks)
3) Genes which are essential to the survival of an organims rarely mutate

49
Q

How is mtDNA inherited?

A

All offspring only inherit their mother’s mtDNA.

50
Q

Is the rate of mutation in mtDNA higher or lower then nuclear DNA? Why?

A

It is higher, as mtDNA has only 37 genes, and mtDNA doesn’t have the same repair mechanisms that nucleur DNA has

51
Q

Briefly explain the steps of DNA-DNA Hybridisation Technique?

A

Two DNA strands which contain the same genes are obtained from two different species, are heated which breaks the hydrogen bonds between nucleotides, causing the DNA strands to become singular. They are then cooled and allowed to pair with each other, via the base pairing rules which is present in all nuclear DNA. The more pairing that occurs, shows how genetically similar the two species are, showing that they diverged from a common ancestor not that long ago, and are fairly closely related.

52
Q

What are Phylogenic Trees?

A

Branching diagrams which can be used to show the evolutionary relationships between different groups of organisms.

53
Q

What is meant by the term ‘Hominoids’?

A

The collective term for apes and all members of the family Hominoidea (including humans)

54
Q

What is meant by the term ‘Hominin’?

A

Collective term for various human species and their bipedal walking ancestors, including Species within the genus’ Homo and Australopithecus.

55
Q

What is meant by the term ‘Primates’?

A

Collective term for all members of the order Primates, which includes apes, monkeys, and members of the Homo and Australopithecus genus’.

56
Q

What 4 common characteristics can be used to identify a Primate?

A

1) 5 digits on hands and feet which allow gripping, along with opposable big toes and/or opposable thumbs.
2) Relatively large brains compared to their body size
3) Social mammals which live in groups ranging from a pair to a troop of hundreds.
4) Stereoscopic Vision

57
Q

What are 4 clear distinctions between Monkeys and Humans?

A

1) Other monkeys like chimps ‘knuckle walk’ while humans are bipedal
2) Human toes are shorter, with the big toe aligned with the others meaning it is not opposable, like monekys
3) Human foot has an arch to assist in bipedal movement
4) Monkey’s arms and legs are generally the same size, unlike humans.

58
Q

What are the 7 common ancestors of Humans which were involved in the evolution of modern Humans,

A

1) Australopithecus afarensis
2) Paranthropus robustus
3) Homo habilis
4) Homo erectus
5) Homo neanderthalensis
6) Homo denisovans
7) Homo sapiens

59
Q

What is one important aspect of the Australopithecus afarensis species?

A

They were the first known species that was bipedal, meaning they are in the hominin group

60
Q

What is one important aspect of the Paranthropus robustus species?

A

They were the first species that began eat meat as shown by the presence of canines.

61
Q

What is one important aspect of the Homo habilis species?

A

They were the first known species to use tools, which resulted them in being called ‘the handyman’

62
Q

What is one important aspect of the Homo erectus species?

A

They were the first known hominins to move out of Africa, and spread across the globe

63
Q

What is one important aspect of the Homo neanderthalensis species?

A

They were the first known hominins who had the capacity for speech and language, as shown by their organised hunting methods

64
Q

What is one important aspect of the Homo denosovans species?

A

There aren’t many fossils found, but the only new information that was obtained was that these were the first hominin species to show interbreeding between Homo sapiens and Homo neanderthals

65
Q

What is one important aspect of the Homo sapien species?

A

They were the first known species to show skilled hunting and gathering, as well as the continuation of the evolution of culture.

66
Q

What are some important STRUCTURAL changes in the Homo sapien evolution line?

A
  • Absence of a prominent brow ridge
  • Brain got relatively larger
  • Skull became more rounded, with the loss of crests
  • Teeth and jaw got smaller
  • Forehead became more sloped then flat
  • Nose and chin became more prominent and round, then flat
  • Face became more vertical then sloped
  • Widening and elongation of Pelvic bone into a more ‘bowl-shaped’
67
Q

What are some important FUNCTIONAL changes in the Homo sapien evolution line?

A
  • Development of canines
  • Development of Bipedalism
  • Loss of body hair
  • Movement of big toe in alignment with the others
  • Changed from living in trees (aboreal) to living on the ground (terrestrial)
68
Q

What are some important COGNITIVE changes in the Homo sapien evolution line, which are also considered to be aspects of Cultural Evolution?

A
  • Began to form speech and language
  • Began to create tools and weapons (technology)
  • Began to create clothing
  • Began to build structures
  • Began to develop communal roles
  • Began to use fire
  • Began to document important things in paintings and drawings (cultural evolution)
69
Q

What does Cultural Evolution mean?

A

Cultural Evolution is the term used to describe the evolution and change in human way of life, as opposed to the biological evolution of modern humans.

Biology 3&4 (14 decks)

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