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Evolution Flashcards

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Biology 101 flashcards
1
Q

What is evolution?

A

The change in characteristics of species over time

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2
Q

What is a species?

A

Group of similar organisms that can successfully reproduce with each other to produce fertile offspring

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3
Q

What is a population?

A

Group of organisms of same species that live together in a particular area at a particular time and are interbreeding with eachother

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4
Q

What is biodiversity ?

A

The variety of life on earth

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5
Q

What is extinction ?

A

When a species disappears forever (death)

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6
Q

What causes extinction ?

A

Predation , competition , disease , lethal mutations , environmental changes, natural disasters and human interferences

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7
Q

What is a theory ?

A

Explanation of something that has been observed in nature which can be supported by facts , generalisations , tested hypotheses , models and laws

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8
Q

What is a hypothesis ?

A

Possible solution to a problem

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9
Q

What is the Theory of Evolution ?

A

Scientific theory since various hypothesis relating to evolution has been tested and verified over time

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10
Q

What is a phylogenetic tree or cladogram?

A

Diagram that represents evolutionary relationships between species

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11
Q

What is palaeontology ?

A

The study of plant and animal fossils

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12
Q

What are fossils?

A

Remains or traces of once living organisms that have escaped decay and been preserved

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13
Q

Where are fossils found ?

A

Ice, sedimentary rock, tree resin, volcanic lava , tar pits of anaerobic swamps

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14
Q

What are the ideal conditions for fossilisation?

A

Should be covered quick after death so anaerobic conditions are created and slow down decomposition

Harder parts preserved

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15
Q

What are the steps in fossilisations ?

A
  1. Plant/animal dies and covered in sediment on land/sea bed
  2. Soft tissue decays, hard parts remain and organic material in mineralised
  3. Sediment covers body in layers compressing it and cementing it together
  4. Fossils encased until exposed via earth movements/erosion/palaeontologists
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16
Q

What is a homologous structure?

A

Similar structures of organisms with common ancestor but not always same function

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17
Q

What are analogous structures?

A

Do not have common ancestor and have similar structures with same function

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18
Q

What is biogeography ?

A

The study of the distribution of species , to find out if the species have a common ancestor

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19
Q

What are some genetic similarities found in common ancestors ?

A

Identical DNA structure
Similar sequence of genes
Similar portions of DNA with no functions
Similar mutations (mDNA)

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20
Q

What is crossing over ?

A

In prophase 1 of meiosis involves an exchange of genetic material leading to new combinations of maternal and paternal genetic material in each new cell resulting from meiosis

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21
Q

What is Random arrangement ?

A

Random segregation of maternal and paternal chromosomes at the equator during metaphase allows different combinations of chromosomes/chromatids to fo into each new cell resulting from meiosis , making them different

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22
Q

What is random fertilisation?

A

Fertilisation between egg cells and different sperm formed by meiosis resulting in offspring that are different from eachother

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23
Q

What is random mating?

A

Random mating within a species leads to a different set of offspring from each mating pair

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24
Q

What is a mutation?

A

Changes the structure of a gene or chromosome and therefore the organisms genotype. Since the genotype influences the phenotype, it creates organisms with new, different characteristics from one generation to the next

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25
Q

What are the two types of variation ?

A

Continuous
Discontinuous

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26
Q

What is continuous variation ?

A

Those characteristics where there is a range of intermediate phenotypes eg height

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27
Q

What is discontinuous variation?

A

Those characteristics that fall into distinct categories eg. Blood groups

28
Q

What are theories of evolution ?

A

Lamarckism (Jean Baptiste de Lamarck)
Darwinism (Charles Darwin)
Punctuated equilibrium (Eldridge and Gould)

29
Q

What two laws is Lamarcks theory based off?

A

The law of use and disuse of organs which can lead to the enlargement or shrinkage of organs

The law of inheritance of acquired characteristics whereby characteristics developed during the life of an individual can be passed on to their offspring

30
Q

What was Lamarcks theory?

A

He thought each species had an independent evolutionary line with a starting point.

Thought organisms changed during their lifetimes based on needs and passed onto new generation. This has been disproved

31
Q

Explain Darwin’s theory of natural selection

A

There is a great deal of variation amongst offspring
Some have favourable characteristics and some do not
In a change of conditions/environment then a characteristic that is suited will survive and unfavourable characteristics die
This leads to those organisms reproducing and pass on the allele for favourable characteristic
Next generation has higher proportion of individuals with favourable characteristics
Similar organisms are related and are descendants of a common ancestor

32
Q

What is punctuated equilibrium ?

A

Explains speed in which evolution takes place

Evolution takes long where species do not change or change gradually over time through natural selection
This alternates with rapid changes which occur through natural selection during which new species form in a short period of time
Evolution occurs as big jumps rather than small steps

33
Q

What is artificial selection?

A

Animal/plant breeding to selectively develop particular phenotypes

34
Q

Describe domestication in dogs

A

Dog first animal to be domesticated by humans
Evolved from wolves
Mature dogs resemble wolf Cubs
Main reason was that they were tame
Humans have adopted wolf pups for tame ness
Today there are 800 different dog breeds
Unfortunately long term breeding of pedigree dogs within a small gene pool often led to inbreeding
In contrast cross breeds show hybrid vigour and fewer ailments

35
Q

Describe domestication of maize

A

Maize most important crop in SA
Grass family (2m tall)
American Indians domesticated from toesinte
Maize is not entirely dependent on humans for propagation and survival
Kernel attached to con so they can’t disperse naturally
Maize cannot compete in wild

36
Q

What is a disadvantage of artificial selection?

A

Removes a lot of variation from a population . Selectively bred organism are prone to disease or environmental changes

37
Q

What is speciation?

A

The formation of a new species when frequency of certain alleles in a population changes

38
Q

What are mechanisms of speciation ?

A

Interbreeding
Geographical isolation
Reproductive isolation

39
Q

What is interbreeding ?

A

Mating of closely related by genetically different individuals. Occur commonly in plants less common in animals

40
Q

What is geographical isolation ?

A

If population is split by a geographical barrier
No gene flow between populations
Exposed to different environment different natural selection
Populations become different from each other
Can’t interbreed if mixed
Two different species

41
Q

What is reproductive isolation ?

A

Isolation maintained by biological barriers preventing two or more populations from cross-breeding and exchanging genes

42
Q

What are the reproductive isolation mechanisms ?

A

Time or seasonal isolation
Behavioural isolation
Plant-pollinator adaptations
Mechanical isolation

43
Q

Explain Time/seasonal isolation

A

Populations become fertile and reproduce at different times of year and may choose to mate during day and not at night

44
Q

Explain behavioural isolation

A

Mating rituals and courtship displays differ between the populations

45
Q

Explain plant-pollinator adaptation

A

Plants evolve to only attract one type of pollinator

46
Q

Explain mechanical isolation

A

Size/position if sex organs in populations differ, fertilisation prevented

Infertile offspring offspring are developed but cannot produce gametes

47
Q

Explain how an infection like TB can lead to antibiotic resistance

A

A person with TB takes antibiotics long enough to kill harmful bacteria
But because the feel better they stop taking antibiotics before the course completed
Random mutations of bacteria leads to bacteria being able to survive antibiotic dosages
They multiply and become drug resistant

Drugs would not help as MULTIDRUG-RESISTANT TB BACTERIA (MDR-TB) evolved
(MDR-TB) developed into EXTENSIVELY DRUG-RESISTANT TB (XDR-TB) which needs 5 drugs

48
Q

Explain resistance to insecticides

A

One insecticide (DDT)being used on a particular insect might become useless (mosquitoes)
Malaria will become hard to control
Mosquitoes will breed quickly and some offspring will have favourable mutations enabling them to detoxify DDT making them resistant
Through natural selection they will survive and pass genes on to next gen
All Mozzysss will be resistant to DDT

49
Q

Explain HIV resistance to ARV’s

A

Occurs same way as when people don’t take ARV’s as prescribed which builds drug resistant bacteria
Most HIV are killed by ARV drugs but strongest survive
Surviving HIV replicate forming new drug resistant population of HIV

50
Q

Explain the natural selection of Galapagos finches

A

13 different species have different bill sizes
Plants produce seeds of different toughness
During wet years plants form smaller seeds, finches will smaller beaks are able to eat more seeds and survive
Larger beaked finches can’t eat the small seeds and starve
During drier years, food limited to tough seeds
Natural selection favours bigger beaks as they can break into the tough seeds and the smaller beaks can’t

51
Q

What family do humans fall under?

A

Hominids

52
Q

What does a phylogenetic represent?

A

The possible evolutionary relationships among a set of organisms

53
Q

What do primates include?

A

humans, apes, orangutans, gorillas and chimpanzees

54
Q

What characteristics do humans share with other primates?

A

opposable thumb
two hands (five fingers)
long arms that rotate freely
naked finger and toe ends with flat nails
reduced snout and weakened sense of smell
forward facing eyes with stereoscopic vision
eyes have cones which make colour vision possible
Large brain in comparison to rest of body
few offspring

55
Q

What characteristics differ between humans and primates?

A

Bipedalism
Brain size
Teeth
Prognathism
Palate shape
Cranial ridges
Brow ridges

56
Q

Define bipedalism

A

The ability to walk on two legs

57
Q

Define quadrupedalism

A

The ability to walk on four legs

58
Q

How to facilitate bipedalism?

A

Opposable big toe became aligned with other toes
Pelvis became larger, shorter, broader to support greater body weight
Ball of femur was angled
Spinal column changed from straight to s-shaped
foramen magnum shifted to forward position

59
Q

What does greater cranial size entail?

A

Greater intelligence
increased ability to live in large groups
communicate via a language

60
Q

How much bigger are human brains compared to that of a chimpanzee?

A

3.5x

61
Q

What skull features do humans have?

A

More rounded skull
No prominent brow ridges
Flatter face
Less protruding jaw
Teeth smaller and more uniform in length (omnivorous)
Curved palate allowing for speech
More centrally placed foramen magnum

62
Q

What evidence supports evolution?

A

Fossil evidence
Genetic evidence
Cultural evidence

63
Q

What do fossils support?

A

They support the idea of common ancestors for living hominids

64
Q

What is used for genetic evidence ?

A

mtDNA

65
Q

How is mtDNA used?

A

Passed down from mother to child and is mutated
Mutations spread between isolated populations
Number of differences in mtDNA between two species tells scientists how long ago the species were separated

66
Q

What is cultural evidence?

A

The use of stone tools to crack nuts
The use of stone tools correlated with increased dexterity and size of cranium

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