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Biology Year 12 > Evolution > Flashcards

Evolution Flashcards

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1
Q

Gene pool

A

The sum total of genetic information present in a population

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2
Q

Selective pressure

A

Environmental conditions that favour certain individuals

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3
Q

Selective advantage

A

Organisms that have better phenotype to survive will have more likely survive and pass them onto the next generation

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4
Q

Is it easier for natrual selection to get rid of a dominate or recessive trait

A

It’s easier to get rid of a dominant trait due to heterozygous Bb have the same selective advantage as BB and when having offspring there is still always a chance for the recessive trait to occur.

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5
Q

What is gene flow

A

Also known as migration
Changes due to migration can occur very quickly
Is directional

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6
Q

What’s genetic drift

A

Is a pattern of random change in allele frequency from one generation to the next
the direction of change is UNPREDICTABLE.
Unlike natrual selection it does not favour one allele over another
Mainly occurs in small populations

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7
Q

What is genetic bottle neck

A

When the size of population is drastically reduced from a bush fire, flood, new disease etc.
The few survivors that reproduce to give the next generation may be an underrepresented sample of the original gene pool

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8
Q

What’s the found effect

A

When a small underpresentative or nonrandom sample of the population leaves to colonies a new region.
The first organisms of the population to start a new colonie are called founders

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9
Q

What’s a mutation

A

New alleles occurring due to mistake in DNA

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10
Q

Whats point mutation

A

Affects a single base in DNA
by substitution
Commonly affect structural genes

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11
Q

What’s a frameshift mutation

A

A three nucleotide (codon) insertion or deletion cause the genes message it encodes to no longer make sense

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12
Q

What’s a block mutation

A

Chromosomal change affecting large segments of a chromosome
Either:
Deletion of part of a chromosome
Duplication or gain of part of a chromosome
Translocation or reciprocal exchange between non homologous chromosomes
Inversions when a segment of a chromosome rotates through 180 degrees

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13
Q

What’s aneuploidy

A

The presence of an abnormal number of chromosomes eg a human cell contain 45 or 47 chromosomes

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14
Q

What’s polyploidy

A

When a cell contains more than two sets of chromosomes

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15
Q

Define natural selection

A

A process by which new heritable traits of organisms better adapted to their environment tend to survive and produce more offspring

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16
Q

What’s the steps of natural selection

A
  • There is variation between individuals
  • Organisms with favoured phenotype will have an improved chance of survival and reproducing.
  • individuals who survive and reproduce increase the chances of passing those genes on to the next generation
  • favoured genes will increase in frequency within the population over time
  • over long period of time the characteristics of the favourable gene will be the most noticeable within the population
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17
Q

Why can’t organisms produced asexually not undergo natural selection

A

They do not have variation between individuals

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18
Q

Living factors of selective pressures

A

Predators , competing for food, water, space, mates, parasites

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19
Q

Non living facfors of selective pressures

A

Changes to temperature, pollutants, availability of water, minerals, light and natural disasters

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20
Q

Define biological species

A

A group of interbreeding individuals, they are often composed of different populations that are quiet distinct these are known as subspecies.

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21
Q

What does speciation mean

A

Refers to the process by which new species are formed
It occurs when gene flow has ceased between populations where it previously exists
Is brought about by development of reproductive isolating mechanisms which maintain the integrity of the new gene pool

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22
Q

What’s the two types of speciation

A

Splitting and budding

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23
Q

What’s splitting speciation

A

A species could split fairly equalling into two populations that envolve differently until they eventually become separate species

Photo

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24
Q

What is budding speciation

A

A small part of species population could “bud off” from main part and evolve rapidly to form a new species while leaving most of the original species population unchanged

Photos

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25
Q

What is allopathic speciation

A

Populations become geographically separated and become subjected to different selection pressures. They establish reproductive isolating mechanisms in isolation.

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26
Q

Step 1 of allopathic speciation

A

Moving into new environment
The population occupies new parts of the environment
The population has a common gene pool that interbreed

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27
Q

Step 2 of allopatric speciation

A

Geographical isolation
Gradual formation of physical barriers may isolate parts of the population at the extremes of the species range
The gene flow between the isolated populations is prevented and becomes rare

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28
Q

Agents causing geographical isolation include

A

Continental drift, climate change and changes in sea level

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29
Q

Step 3 of allopatric speciation

A

Formation of subspecies
Isolated populations have different selection pressures that will favour the individual traits suited to each environment
Natural selection occurs

30
Q

What’s atage 4 of reproductive isolation

A

Each sub species develops reproductive isolating mechanisms

Even if geographical barriers are removed the species will no longer breed with each other

31
Q

What is artificial selective/ selective breeding

A 
Involves breeding (selecting) from individuals with the most desirable phenotype.
Selection imposed by humans is more intense and rapid then occurring in nature
32
Q

How does artificial/ selective breeding occur

A

Artificial insemination, embryo transfer,

33
Q

Does Loss of genetic variation matter

A

When a disease occurs if all the species are the same they will die out eg when the potato famine occurs one million Irish pease te died due to not having enough potatos to feed on.
Variation is needed if the environmental conditions changes

34
Q

What are scientists doing to stop a disease in crops destroy everything

A

The keep seed banks and gene banks that seek to conserve diversity in plant species

35
Q

What are fossils

A

Any parts or impressions of an organism that may survive after death

36
Q

When do fossils form

A

Only under special conditions:
Anything from water has more chance of forming a fossil
Fossils form best when organisms are buried quickly as it slows the decay process

37
Q

What types of rocks are fossils most commonly found

A

Sedimentary rock

38
Q

What’s a fossil rock profile

A

Layers of sedimentary rock arranged in the order they were laced down. The most recent layers are near the surface

39
Q

Define evolution

A

Permanent genetic change in a population of individuals over an extended period of time

Does not refer to changes occurring to individuals over their own life time

40
Q

What’s the two types of evolution and explain

A

Micro evolution- describes small scale changes which gene pools over generation

Macro evolution- large scale changes in form as viewed in the fossil record involving whole groups of species.

41
Q

Index fossils

A

Fossils used to identify geological periods

42
Q

Transitional fossil

A

Fossils that are intermediate between ancestral and descendant species.
They show evolutionary transition

43
Q

What’s absolute dating

A

If a fossil can be accurately age then it is easier to form accurate time of life

44
Q

Radiometric/ isotopic dating

A

More accurate way of dating fossils. The method measures the amount of isotopes that are radioactive in either the fossil or rocks the fossil is found in

45
Q

What’s radio carbonate dating

A

Used to identify the age of young fossils.
Carbon is found in dead remains of organisms. Most of carbon is non radioactive carbon 12 while a small amount is in form of carbon 14 is radioactive.
Carbon 14 breaks down into nitrogen 14
Carbon 12 will not break down
By comparing the amount of carbon 14 with nitrogen 14 you can get a more accurate age

46
Q

The diagram for radio carbonate dating

A

Photos

47
Q

Homologous structures

A

Structure in different organisms that have a similarities present as a result common ancestory.
Even though they may serve a different function as they have been adapted for a different purpose.
Eg wing, arm, leg etc
This provides evidence for divergent evolution

48
Q

Anologous structures

A

Have similarities between species but is not inherited from a common ancestor
Structures that have the same function in different organisms may come from different origins
Eg wings on birds and butterflies
May indicate convergence evolution

49
Q

What is DNA hybridisation used for

A

One way to reconstruct the evolutionary history of species

50
Q

What is the process of DNA hybridisation

A

DNA from two different species is unzipped and recombined to form hybrid DNA
Heat is used to separate the hybridised strands
The amount of heat required to do this is a measure of how similar the DNA strands are (%bonding)
More heat required displays that there are more bonds equalling DNA to be similar
Less heat required for very different species

51
Q

Amino acid sequencing in evolution history

A

Closely related species have proteins with similar amino acid sequences
The degree of similarity of these proteins is determind by the mutations that have occurred.
The greater the time since common ancestry= more mutations

52
Q

What is divergent evolution

A

When closely related species become more dissimilar over time usually in response to different environmental conditions and selection pressures

53
Q

What’s an example of divergent evolution

A

Galapagos island finches

Natural selection occurred resulting in different species of birds changing to suit the foods they eat on the islands

54
Q

What is convergent evolution

A

Occurs when similar features develop independently in organisms that are not clearly related but may live in similar environments.
Eg a wolf ang tiger

55
Q

What’s a mass extinction

A

A period in the geologic history of the earth during which an abnormally high number of species die out over a relatively short time frame

56
Q

What is mitrochondrial DNA

A

Another piece of evolutionary evidence
MtDNA inherited from the mother only
By comparing mtDNA in populations it is possible to trace the origin of mtDNA to a female ancestor in Eastern Africa called mitrochondrial eve

57
Q

Gene regulation and natrual selection

A

Two important genes in Darwin finches
BMP4 a regulatory gene- this gene stimulates the production of material that makes beaks
CAM-a gene that regulated calcium that makes the shape of the beak
When BMP4 is turned on early the CAM gene is turned on late then a short break occurs

58
Q

What’s the molecular clock do

A

Uses mutation rates in DNA to estimate the time two species split and evolve independent

59
Q

What does the molecular clock theory rely on

A

The Mutations are neutral, they do not affect phenotype

The mutations occur at a fairly regular Occassion

60
Q

What does each degree below 87 degrees represent in DNA hybridisation

A

The percentage of difference in the DNA

61
Q

What’s the first group of organisms that show human features

A

Primate- advanced group of mammals that share common characteristics

62
Q

Characteristics of primates

A

Vision- large forward facing eyes with 3D vision
Face- snout is reduced and sense of smell also
Collarbone-ability to rotate the arm so it can extend behind the body
Posture- upright and erect posture at times
Hands-opposable thumb
Reproduction- maternal instincts exist
Social organisation- live in groups

63
Q

What’s hominoids

A

Grouping of greater and lesser apes including gorillas, chimpanzee and humans

64
Q

What’s a hominins

A

Modern human species and our extinct close relatives that could walk erect on their hind legs in a sustained fashion

65
Q

What happened to the foraminifera magnum over time

A

Moved further forward so the skull is balanced on the spine

66
Q

What’s cultural evolution and examples

A 
Changes in human societies over time where those changes are socially passed on and not genetically
Eg domestic animals 
Burials and rituals 
Totems
Paintings
67
Q

What’s technology evolution

A

Development of technology that gives humans increased control over their environment. It has increased at an exponential rate. The rapid increase of tools is directly related to cultural evolution and increase in brain size

68
Q

Human evolution 5 significant developments over 5 million years

A
  1. Hind limbs become longer so forelimbs no longer drag
  2. Stance progressively became upright due to change in position of foramen magnum
  3. The brain capacity increase=increase intelligence
  4. The size of jaw decreased
  5. Thumbs became fully opposable. Toes straighten and arc develops in feet
69
Q

What’s the out of Africa model

A

Homo sapiens sapiens have common origin in Africa. Members from Africa migrated out. Supported by mitrochial DNA

70
Q

What’s classified as a young fossil

A

40,000-50,000 years old

71
Q

What causes antibiotic resistance

A

Any mutation that provides an advantage under certain selection presses may spread quickly through bacteria population
This has created the selective environment for increased frequency of antibiotic resistance genes in populations

72
Q

Relative dating vs absolute dating

A

Absolute dating is the exact age of a fossil eg

Relative dating is the relation of age compared to rock layers around it eg the fossil position in the layer of rocks

Biology Year 12 (8 decks)

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