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GCSE Biology > B7 Variation And Evolution > Flashcards

B7 Variation And Evolution Flashcards

1
Q

Environmental variation

A 
Changes due to the environment 
Tattoos 
Scars
Language
Hair colour and length
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2
Q

Genetic variation

A 
Differences from our genes
Blood group
Eye colour
Shape of earlobe
Natural hair colour
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3
Q

Genetic and environmental factors

A 
A mixture of both
Height
Skin colour
Weight 
Sporting abilities
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4
Q

Variation and survival

A

Variation is critical for survival and for evolution

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5
Q

Genetic variation

A

The product of 3 processes that lead to differences in genomes: mutations, sexual reproduction and meiosis
Most mutations have no effect and rarely change the phenotype

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6
Q

An early theory of evolution

A

French scientist Jean-Baptiste Lamarck in 1809
Organisms survived by adapting to their environment passed on this adaption to the next generation
Eg. Giraffes necks were stretched and then passed to next generation

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7
Q

How does evolution happen?

A

The environment does influence the phenotype but not in the way Lamarck suggested
Desired characteristics are passed to their offspring eg.resistant to antibiotics

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8
Q

Natural selection

A

When desired characteristics are passed to their offspring

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9
Q

Environmental changes

A

Geographical isolation, change in climate causes species to adapt differently
Overtime they will develop characteristics different to those or the original species

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10
Q

Darwin’s theory

A

He noticed that animal where the similar but not the same

This lead to the idea of natural selection and evolution

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11
Q

Natural selection

A

The most advantageous characteristics are passed on

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12
Q

Evolution

A

Species are changing and adapting through natural selection in order for survival

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13
Q

How are fossils formed?

A

By dead animal or plants being buried in mud,silt or sand
There is no oxygen so that organisms can not decay the body
Hard parts of animals like bones are fossilised
Can also be trapped in amber or volcanic ash

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14
Q

Evidence from fossil records

A

Older fossils are near the bottom

We can see which species have adapted, survived or died out

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15
Q

Radiometric dating

A

Allows us to identify the exact age of the fossil.

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16
Q

Incomplete fossil records

A

Geological activity has destroyed them
May be lost
Soft bodied organisms can not be fossilised
Missing links between species

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17
Q

Evolution of life

A

Some species have changed a lot whilst others have evolved very slowly
Some bacteria have changed very little as there is still chemical evidence of them in fossils

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18
Q

Warning colouration

A

To deter predators

Favoured by natural selection

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19
Q

Mimicry

A

Unrelated species develop similar warning colourations to help promote their survival

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20
Q

Isolation

A

Geographical isolation causes species to develop different advantageous characteristics
Eventually it will reach a point where the new species can no longer interbreed with the original species to form fertile offspring

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21
Q

Speciation

A

A species that evolves through natural selection to form a new species

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22
Q

Selection pressures

A

Pressures such as food, water, shelter creates competition to which only the best suited species survives and passes on its characteristics

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23
Q

Melanic moths

A

They changes colour from white/pale to a darkened colour in the industrial revolution to help it survive longer

24
Q

Melanism

A

When a species changes its phenotype stop help survive longer

25
Genetic variation
Similar species breed together to provide a greater gene pool in which there is differences so that some species may survive longer than others
26
Gene theory
Genes work by controlling enzyme synthesis | Genes code for proteins
27
Antibiotic resistance | MRSA
This occurs through people not completing their course so the worse bacteria is exposed to the antibiotic. It can then develop resistance. The resistance gene can be passed to other bacteria through plasmids
28
Reducing AMR
People completing the course No sharing prescription Not skipping doses Only prescribing when necessary
29
Solving the problem
Global governments working together Encouraging pharmaceutical companies to develop a new drug Economically challenging for pharmaceutical companies New strains may not be the most effective over a long time Advances in genes may be a solution to the problem
30
Selective breeding
Interbreeding species to get desired characteristics which will be more advantageous
31
Problems with interbreeding
Creates a small gene pool with little variation | Species can become accustomed to diseases which threaten their health and survival
32
Beneficial characteristics for crops
Grow and mature quickly Distinctive taste, colour or aroma Long shelf life Can be frozen
33
Environmental change
genetically modified crops can be wiped out from a change due to little variation and resistance to new diseases
34
Traditional plant breeding
Using plants from a mixed selection to produce a plant then cross breeding with other plants till the desired phenotypes are produced
35
Producing a new variety
It takes a long time as it has to be grown and put through selection pressures to ensure it is different and is different form other similar species
36
Genetic engineering
Taking the desired characteristics of two species and putting them together
37
Insulin
We can genetically engineer bacteria to produce insulin
38
Genetically modified crops
They increase yields and produce better more desirable produce. It ensures crops are not lost to diseases
39
Genetic engineering technique
An enzyme is used to isolate to gene that codes for proteins. The insulin gene is cut out and placed in a plasmid that is cut open by the same enzyme The insulin gene is inserted into the plasmid The plasmid is put back into the bacterial cell The genetically modified bacteria are cultured
40
Feeding the world
GM crops can contain extra nutrients to help ensure people get the vitamins required Eg. Golden rice contains beta carotene which helps code for vitamin A to help with eye sight
41
Herbicide and insecticide resistant crops
GM crops can produce toxins to kill insects without damaging the plant. This produces a greater yield
42
Ecological effects
Whilst there is concerns about pollen containing toxins that will damage other species (possibly through cross pollination), GM crops generally only kill pests that are eating the plant.
43
Gene markers
Helps identify GM species or antibiotic restraint genes. | It can be dangerous to the survival of species as it is easier for predators to identify them
44
GM safety
Some speculate that it may cause allergic reactions but it may be used to prevent people getting reactions Like wise some people say it may cause cancer or autism This has only been some what proven with the use of glyphosate Which is described as harmless to us, animals and the environment
45
Ethics of GM
Not ethical as you are altering Gods creation | However it may be beneficial for the survival of mankind
46
Producing and marketing GM crops
Farmers can not sow seeds from GM crops as they wont breed true instead they have to buy new seeds. Essentially exploiting poorer farmers Have to label GM crops clearly so costumers can decide whether to buy them or not to.
47
Gene therapy
By using a vector we may be able to help treat genetic disorders however it poses many challenges Many got sick from vectors in early trials There is no guarantee that offspring will get the modified genes Very technically and ethically difficult
48
GM cloning
Cloned in small groups (tissue cultures) | Can produce rare plants
49
Embryo transplants
Allow the cloning of animals to occur early on within a pregnancy
50
Adult cell cloning
``` Nucleus is combined with an egg cell An electric shock stimulates the cell to divide by mitosis Embryo has divided into a ball of cells Embryo implanted into an adult female Clone of sheep is born ```
51
Binomial system
``` Kingdom Phylum Class Order Family Genus Species ```
52
Evolutionary trees
Come from organisms alive today and from fossil records Also look at base sequences of portions of DNA, or the structures of other chemicals such as proteins Looks at bit like a family tree
53
Mass extinctions
Fossil records show there are 5 main extinctions | They are generally from a change in the environment
54
Causes of extinctions
``` New predators Compete with native organisms that are present for food Introduction of new species Change in the environment Invasive or new species ```
55
The sixth mass extinction may be occur because humans are
Transforming the landscape Over exploitation of species Pollution Introduction of alien species

GCSE Biology (8 decks)

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