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Evolution Flashcards

(66 cards)

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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
What are the two types of variation ?
Continuous Discontinuous
26
What is continuous variation ?
Those characteristics where there is a range of intermediate phenotypes eg height
27
What is discontinuous variation?
Those characteristics that fall into distinct categories eg. Blood groups
28
What are theories of evolution ?
Lamarckism (Jean Baptiste de Lamarck) Darwinism (Charles Darwin) Punctuated equilibrium (Eldridge and Gould)
29
What two laws is Lamarcks theory based off?
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
What was Lamarcks theory?
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
Explain Darwin’s theory of natural selection
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
What is punctuated equilibrium ?
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
What is artificial selection?
Animal/plant breeding to selectively develop particular phenotypes
34
Describe domestication in dogs
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
Describe domestication of maize
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
What is a disadvantage of artificial selection?
Removes a lot of variation from a population . Selectively bred organism are prone to disease or environmental changes
37
What is speciation?
The formation of a new species when frequency of certain alleles in a population changes
38
What are mechanisms of speciation ?
Interbreeding Geographical isolation Reproductive isolation
39
What is interbreeding ?
Mating of closely related by genetically different individuals. Occur commonly in plants less common in animals
40
What is geographical isolation ?
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
What is reproductive isolation ?
Isolation maintained by biological barriers preventing two or more populations from cross-breeding and exchanging genes
42
What are the reproductive isolation mechanisms ?
Time or seasonal isolation Behavioural isolation Plant-pollinator adaptations Mechanical isolation
43
Explain Time/seasonal isolation
Populations become fertile and reproduce at different times of year and may choose to mate during day and not at night
44
Explain behavioural isolation
Mating rituals and courtship displays differ between the populations
45
Explain plant-pollinator adaptation
Plants evolve to only attract one type of pollinator
46
Explain mechanical isolation
Size/position if sex organs in populations differ, fertilisation prevented Infertile offspring offspring are developed but cannot produce gametes
47
Explain how an infection like TB can lead to antibiotic resistance
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
Explain resistance to insecticides
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
Explain HIV resistance to ARV’s
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
Explain the natural selection of Galapagos finches
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
What family do humans fall under?
Hominids
52
What does a phylogenetic represent?
The possible evolutionary relationships among a set of organisms
53
What do primates include?
humans, apes, orangutans, gorillas and chimpanzees
54
What characteristics do humans share with other primates?
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
What characteristics differ between humans and primates?
Bipedalism Brain size Teeth Prognathism Palate shape Cranial ridges Brow ridges
56
Define bipedalism
The ability to walk on two legs
57
Define quadrupedalism
The ability to walk on four legs
58
How to facilitate bipedalism?
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
What does greater cranial size entail?
Greater intelligence increased ability to live in large groups communicate via a language
60
How much bigger are human brains compared to that of a chimpanzee?
3.5x
61
What skull features do humans have?
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
What evidence supports evolution?
Fossil evidence Genetic evidence Cultural evidence
63
What do fossils support?
They support the idea of common ancestors for living hominids
64
What is used for genetic evidence ?
mtDNA
65
How is mtDNA used?
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
What is cultural evidence?
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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