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Biology > Evolution > Flashcards

Evolution Flashcards

1
Q

Variation

A

Differences in characteristics of individuals in a population

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2
Q

3 causes of variation in any population

A

-Inheriting different alleles from parents like hair colour
-Environment changes like colours of flower due to soil
-Combo of environment + genetics like height

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3
Q

What causes the genetic variation in species?

A

Mutations or random changes in DNA

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4
Q

Types of mutations

A

-No effect on the phenotype
-Influence the phenotype under certain circumstances
-Completely determine the phenotype (rarely)

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5
Q

How do mutations effect a population?

A

If the environment changes
A mutation could help them survive or resistant to change
Thus the surviving organisms will have a different phenotype
And will be inherited by all other organisms
Which is the baseline for evolution

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6
Q

How have different species come to be on earth?

A

All have evolved over very long period of time from simple single cells
Through evolution by natural selection

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7
Q

Stages of natural selection aka evolution

A

Species have a lot of genetic variation for diff phenotypes
If the environment changes, those with alleles to adapt to this change more likely to survive
Thus more likely to reproduce
And their offspring could inherit this allele then reproduce
Thus over time the whole population will have this phenotype

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8
Q

Evolution

A

The change in inherited characteristics of a population over time through natural selection

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9
Q

How does an animal differentiate into 2 different species?

A

If 2 populations of species become so different in phenotype over a period of time
Due to evolution
That they can no longer interbreed and produce a fertile offspring
= 2 separate species

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10
Q

Selective breeding

A

When humans decide which animals/ plants with a specific phenotype to breed in order to get an offspring with a desired phenotype
Pretty much speeding up the process of evolution but so they’re more useful to us

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11
Q

Examples of selective breeding

A

Dogs = more gentle nature
Crops = disease resistance
Cattle = more milk/ meat
Plants = large flowers

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12
Q

Stages of selective breeding (cows for meat)

A

Take mixed population of cows and select largest male + female
Breed them
Sexual reproduction = variation so some offsprings don’t have desired characteristic
So select the largest male and female offspring from that
Breed them
Repeat for many generations until all offsprings are large

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13
Q

Big problem with selective breeding

A

Breeding closely related animals/plants = inbreeding
Which cause being prone to disease or inherited defects

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14
Q

Genetic engineering

A

When a gene from one organism with a specific characteristic
Is taken from an organism
And transferred to another when in development so it has that characteristic

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15
Q

Using genetic engineering for type 1 diabetes

A

Putting the insulin producing gene in bacteria from a human
Then purified
So it produces insulin
Thus can help treat type 1 diabetes

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16
Q

Genetically modified

A

When you transfer a human gene to an organism to make it carry out a specific function/ have a specific characteristic

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17
Q

Why would we genetically modify crops?

A

Produce a greater yield
Resistant to disease/ insects
Produce bigger fruits
Resistant to herbicides so farmers can kill weeds but not harm the crops

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18
Q

Disadvantages of genetically modified crops?

A

Possibly harm insects
Or wild flowers
Health effects if humans eat it needs more research

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19
Q

Gene therapy

A

Using genetic modification to cure inherited disorders in humans

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20
Q

Disadvantages of gene therapy

A

We don’t know long term effects
Don’t know if it has effects on other genes

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21
Q

Steps of genetic engineering

A

Identify gene we want to transfer (from animal/human/plant)
Use enzymes to isolate it
Transfer gene into a circle of dna called plasmid from bacteria, or into a virus
Desired gene is transferred into target organism

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22
Q

Vector

A

The plasmid or virus that transfers the DNA from one organism to another

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23
Q

In genetic engineering Why do we transfer gene at an early stage in the target organisms development?

A

Make sure all cells receive the transferred gene
So the organism develops with this characteristic

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24
Q

Clone

A

Organism genetically identical to its parent

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25
Q

Advantages of cloning plants

A

Because it’s genetically identical to parent we know what it’s characteristics will be

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26
Q

Cloning plants using cuttings

A

Take small cutting of plant
Dip the end in rooting powder
Thus the plant develops roots
And is genetically identical

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27
Q

What method to get hundreds of clones of a plant?

A

Tissue culture

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28
Q

Tissue culture stages

A

Take parent plant
Divide into many small pieces
Containing small number of cells
Incubate with plant hormones
So the plant is stimulated to grow and develop fully grown clones

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29
Q

Conditions for tissue culture

A

Sterile
So we don’t have any microorganisms like bacteria or fungi

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30
Q

Adv of tissue culture

A

Thousands of genetically identical plants quick and cheap (commercially)
We can be certain of characteristics
Preserves rare species

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31
Q

Who began classifying species?

A

Carl Linnaeus

32
Q

Classification system Linnaeus developed

A

2 kingdoms: plant and animal
Each then divided into smaller categories

33
Q

What were the smaller categories Linnaeus developed?

A

Kingdom
Phylum
Class
Order
Family
Genus
Species

34
Q

How to remember smaller categories Linnaeus came up with

A

Kingdom = King
Phylum = Philip
Class = Came
Order = Over
Family = For
Genus = Good
Species = Soup

35
Q

Binomial name system

A

Species name is:
Genus + species
Eg homo sapien

36
Q

What is Linnaeus system based on?

A

Characteristics we can physically see

37
Q

Why did Linnaeus system change

A

Advances in science so we don’t have to base it on what we see
We can use tech to Analyse dna

38
Q

What classification system is used now?

A

Three domains

39
Q

Who came up with three domain system

A

Carl woese

40
Q

What’s in the 3 domain system?

A

Archae (primitive bacteria) in hot springs
True bacteria (in our bodies)
Eukaryota (animal, plants, fungi, protists, amoeba)

41
Q

How can we tell how closely related species are?

A

Evolutionary tree
The length of time goes up the scale at the side

42
Q

How to make an evolutionary tree?

A

Use classification data on living ones like dna
But if it’s extinct we use fossils

43
Q

Problem with evolutionary tree

A

Extinct creatures can only be judged on fossils
But records of fossils for some are incomplete

44
Q

How do evolutionary trees work?

A

Where it crosses = common ancestor

45
Q

Fossils

A

Remains of organisms from millions of years ago in rocks

46
Q

How can fossils form?

A

If conditions for organism to decay aren’t there thus it doesn’t ie too cold, no oxygen or water
If the organism decays but is replaced by minerals
By traces of organisms like footprints

47
Q

Problem with fossils

A

Most organisms didn’t have skeleton (soft body)
And didn’t form fossils
And the ones that did were destroyed due to changes in earths crust

48
Q

What do fossils show

A

Huge number of species that have been extinct

49
Q

Ways of cloning animals

A

Embryo transplants
Adult cell cloning

50
Q

Embryo transplant stages

A

Sperm and egg cell from target mammal with desired characteristics
Produces fertilised egg
Develop into early stage embryo
Use glass rod to split in 2
Transplant this into 2 host mothers to give birth
Therefore have 2 identical offspring = clones

51
Q

Why must we separate an early stage embryo into multiple embryos during embryo cloning?

A

So the cells don’t specialise into specialised cells before they can be split

52
Q

Problem with embryo transplants

A

Because it undergoes fertilisation in sexual reproduction, we can’t be certain it has desired characteristics as it’s varied

53
Q

How can we overcome the problem with embryo transplants?

A

Use adult cell cloning instead

54
Q

Benefits of adult cell cloning

A

Cloning from an adult = we know what characteristics it will have

55
Q

Stages of adult cell cloning

A

Take cell from target animal
Remove nucleus
Take unfertilised egg cell from same species
Take the nucleus out of this egg cell and throw it away
So we insert nucleus from original target animal cell
So now it only contains genetic info from target animal
Give it an electric shock so it divides = embryo
As the embryo develops, put in host mother to continue development

56
Q

Why does the host mother and clone look different in adult cell cloning?

A

Because we are NOT cloning the host mother!!!!
She is acting as a surrogate to give birth to it and provide it with what it needs
We are cloning a different animal

57
Q

Evolution by natural selection (triple science)

A

In a species there is lots of genetic variation for characteristic
Ones with characteristics most suited to environment can breed most successfully
So the useful characteristic could be passed to next generation

58
Q

On the origin of species

A

Darwin’s theories of evolution published book

59
Q

Origin of species book reception at the time

A

Very controversial
Only became gradually accepted

60
Q

Why was Darwin’s work not accepted at first?

A

Strong belief god made everything
Some felt he did not have enough evidence
Not understanding of how things are inherited

61
Q

Jean baptise Lamarck theory

A

If characteristic is regularly used it develops more thus passes to its offspring

62
Q

Problem with Lamarcks theory

A

Changes due to environment are not passed onto offspring
So it’s incorrect

63
Q

Wallace’s theory

A

Same evolution by natural selection theory as Darwin
Came up with it separately at the same time
So they jointly published their studies

64
Q

Speciation

A

How new species form from different animals

65
Q

What did Wallace notice when studying speciation?

A

Closely related species are separated by geographical barriers eg a river

66
Q

How do new species form?

A

If a geographical barrier separates a population
The population could once interbreed and spread mutations
But now they can’t breed
And natural selection favours different alleles on either side that will change the population
Thus 2 they can’t spread this mutation and will develop into separate species

67
Q

How do we know when we have developed a different Species?

A

Can no longer interbreed to produce a fertile offspring

68
Q

Who came up with many of the discoveries of genetics?

A

Gregor Mendel

69
Q

How did Mendel carry out experiments?

A

Looked at shape of the pea pods and its flowers

70
Q

What did Mendel’s experiments show him?

A

Genes aren’t blended together but we get how we look from inherited units
These don’t change as we pass them down
These could be masked and reappear with later generations

71
Q

How was mendel’s work accepted?

A

Scientists studied cell division and saw chromosomes act in a similar way to what Mendel said

72
Q

What organisms evolves extremely quickly?

A

Bacteria under ideal conditions

73
Q

Examples of antibacterial resistant

A

MRSA

74
Q

What causes bacteria resistance to antibiotics?

A

Mutation causes one to be resistance to antibiotics
Antibiotic kills all bacteria except the resistant one
So it begins to reproduce with no competition = resistant strain rises and spreads

75
Q

How to reduce bacteria resistance?

A

Not prescribe antibiotics inappropriately
Patients complete course of antibiotics so none can mutate
Restrict use in farming

76
Q

Problem with creating new antibiotics

A

Too slow and expensive
Once developed it can’t keep with the new strains of resistant bacteria

Biology (55 decks)

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