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Biology Aqa Science > Topic 6c Evolution and classification > Flashcards

Topic 6c Evolution and classification Flashcards

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1
Q

What is variation

A

Variation is all the differences in the characteristics of individuals in a population

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2
Q

What is Genetic variation

A

Genetic variation refers to the variation in characteristics determined by genes inherited form our parents. Fusion of gametes creates genetic variation within a population

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3
Q

What is Environmental Variation

A

Environmental variation refers to the differences in characteristics of individuals in a population caused by the environment where an organism lives

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4
Q

Give an example of Environmental Variation

A
  • Language in humans is caused by the environment we live in
  • Plant growth is strongly influenced by environmental factors e.g. Plants exposed to more favourable environmental conditions will be healthier i.e. sunlight mineral content in soil,
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5
Q

Give an example of Genetic and Environmental variation

A

Height - The max height that a plant or animal can grow is determined by its genes (GENETIC). But whether or not the organism reaches their max height potential can be down to the environment they live in e.g. the amount of food, enough calcium for their bone to fully develop (Environmental).

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6
Q

What is a mutation

A

A mutation is a random change in an organisms DNA. A change to the sequence of Bases in DNA

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7
Q

Explain why most mutations have no effect on an organisms Phenotype

A

Most mutations have very little to no affect on the protein the gene codes for meaning that the protein is changed to such a little extent that it still performs the same function. So mutations have no affect on the organisms phenotype

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8
Q

Your sporting ability may be affected by your genes and your environment. suggest one environmental factor which may affect your sporting ability

A

The training facilities you may have access to, The amount of time you are able to train

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9
Q

What is the theory of evolution

A

All of today’s species have evolved form simple life forms that first started to develop over three billion years ago.

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10
Q

According to the theory of evolution how long ago did life on earth begin

A

three billion years ago

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11
Q

According to the theory of evolution, how did complex organims come to exsist on earth

A

They evolved from simpler organisms

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12
Q

What is natural selection

A

The natural process by which species evolve and the best adapted individuals survive longer, have more off spring and thereby spread there characteristics.

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13
Q

What is natural selection

A

The natural process by which the best adapted individuals survive longer, have more off spring and thereby spread there characteristics.

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14
Q

Warfrin is a chemical used to kill rats. It is now less used as many rats have became resistant to it.
Using the theory of evolution by natural selection explain why rats have become resistant to the drug warfrin.

A
  • Variants in the original rats genetic make up showed some rats were resistant to warfrin whereas others weren’t.
  • Rats with the genetic mutation making them resistant to warfrin were better suited to the environment so had a better chance of survival.
  • This meant they were more likely to breed and pass on their genes (Warfrin resistance) to the next generation
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15
Q

What was Gregor Mendel known for

A

noting characteristics were passed of from generation of plants to the next (the idea of inherited units)

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16
Q

What is speciation

A

When the phenotype (characteristics) of the same species change so much due to natural selection (geographical barrier) that a completely new species is formed and they can no longer produce fertile offspring

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17
Q

For what reasons do species become extinct

A

Rapid Environmental changes e.g. destruction of habitat
Disease kills all species
Anew predator kills all species
Catastrophic event e.g. volcanic eruption or collision with an asteroid

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18
Q

For what reasons do species become extinct

A

Rapid Environmental changes e.g. destruction of habitat

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19
Q

Anteaters feed on insect such as ants. they have evolved extremely long tongues to reach into ant nests

Suggest how Lamarck’s theory may have explained the evolution of lounge tongues in anteaters.

A

Lamarcks theory = repetitive use develops certain characteristics passed on to offspring
Lamarcks theory would have suggested that the anteater would have developed the characteristically long tongue through repetitive use over a lifetime and pass it on to their offspring.

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20
Q

Anteaters feed on insect such as ants. they have evolved extremely long tongues to reach into ant nests

Suggest how scientists would have explained the evolution of long tongues in anteaters using the theory of natural selection

A

Scientists would argue that the anteaters would carry the gene allele for a long tongue and short tongue due to genetic variants. Those anteaters carrying the gene for the long tongue would survive longer than those without as they are able to get more food and therefore they would breed and the gene for a long tongue would be passed on to their off spring.

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21
Q

What is selective breeding

A

selective bleeding is when humans artificially select plants or animals that are going to breed so that the genes for a specific characteristic remain in the population.

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22
Q

Give an example of a feature that an organism might be selectively bred for

A

features that are considered attractive or useful:

  • Animals that produce more meat or milk
  • Crops with disease resistance
  • Dogs with a good, gentle temperament
  • Decorative plants with big unusual flowers
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23
Q

Explain one problem associated with selective breeding

A

It reduces the gene pool which is known as inbreeding. Inbreeding can cause health problems, such as genetic defects and susceptibility to disease. Due to the lack of variation of alleles in the gene pool, if a new disease appears there’s less of a chance of an organism possessing any disease resistant alleles.

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24
Q

What does genetic engineering involve

A

Cutting out and transferring a gene responsible for a desirable characteristic from one organism’s genome (genetic make up) into another organism, so that it has the desired characteristic.

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25
Q

In genetic engineering why are useful genes sometimes transferred into animals and plants in the early stages of development.

A

It means that the organism will develop with the characteristic coded for by the gene

26
Q

Give an example of a characteristic that bacterial cells have been engineered to have

A

Bacterial cells have been engineered to produce human insulin

27
Q

What does GM mean and what can GM crops be made resistant to

A

Insects, Viruses and herbicides

28
Q

How are vectors used in genetic engineering

A
  • A useful gene is cut out from an organism using enzymes and inserted into a vector (DNA molecule used to carry additional genetic material into a cell)
  • Vector would usually be a virus or bacterial plasmid.
  • The vector is then introduced to the target organism and the useful gene is inserted into the cell.
29
Q

B thuringenesis is a bacteria which produces a crystal protein poisonous to insects. Suggest the benefit of genetically engineering a crop that produces this protein

A

If insects eat the crop they would be poisoned. If less insects eat the crop the yields would be higher

30
Q

Suggest a possible risk of growing crop plants that have been modified to produce B thuringenesis

A
  • could affect the number of wild plants living in and around the crop
  • People may develop allergies to the crop
  • Transplanted genes may get out into the natural environment (nuisance weeds which may have previously been eaten by insect may start to produce the crystal which kills insects and in turn they will not be eaten and continue to grow more)
31
Q

What are the benefits to GM Crops

A
  • Characteristics chosen for the GM crops can increase yield, making more food
  • GM crops can be grown to contain specific nutrients that people living in developing countries may have previously been lacking in
32
Q

What is cloning

A

Cloning refers to the process of making an exact genetically identical copy of an organism

33
Q

What are the two types of plant cloning

A

Tissue culture:

  • Tissue is taken from the tip of the parent plant (Meristem tissue)
  • Placed on a medium containing growth hormones
  • Grown into new plants

Cuttings:

  • Cuttings are taken from the parent plant, each with a new bud on them
  • Cuttings are kept in moist conditions until they are ready to plant
  • Cuttings a planted and new plants are grown which are genetically identical to the parent plant
34
Q

What benefits are associated with cloning plants through taking cuttings

A

Plants can be produced quickly and cheaply

35
Q

Name and explain the two methods of animal cloning

A

Embryo transplant:

  • Embryo is created by using sperm to artificially fertilise an egg cell
  • The early embryo that develops is split many times to produce clone cells
  • Cloned embryos are implanted into many organisms
  • When they new organisms are born they are genetically identical to the parent

Adult Cell cloning:

  • Remove nucleus form an unfertilised egg cell
  • Remove nucleus from an adult body cell
  • Insert nucleus from adult body cell and insert it into unfertilised egg cell
  • The egg cell is then stimulated by an electric shock which makes it divide
  • The embryo is then implanted into the uterus of an adult female where it grows into a clone of the original adult cell.
36
Q

scientists are taking the nucleus from the skin cell of an adult black footed cat (Endangered species) and implant them into the egg cell of a domestic cat. Once dividing the embryo will be implanted into the uterus of the domestic cat.

Would an embryo created by the sciencetists method share the same genetic information as the domestic cat

A

No because the nuclues containing the genetic material of the domestic cat would have been removed from the egg cell. It would share the same genetic material as the black footed cat.

37
Q

scientists are taking the nucleus from the skin cell of an adult black footed cat (Endangered species) and implant them into the egg cell of a domestic cat. Once dividing the embryo will be implanted into the uterus of the domestic cat.
Suggest how the following could help to save the black footed cat
1. using common domestic cats as surrogate mothers rather than black footed cats
2. Being able to take skin cells from black footed cats that have already died as well as ones that are still alive

A

There are an abundance of common domestic cats to implant embryos into so there is more chance of creating large numbers of offspring of black footed cats

Using cells from both dead and alive cats may increase the number of parents meaning more black footed cats may be produced

38
Q

What concerns may people have regarding the cloning of cells in order to save endangered species

A

Cloning may reduce the gene pool creating fewer variations of alleles in the population. If a new disease appears the whole population could be wiped out as there may not be a disease resistant allele in the population
It is possible that cloned animals may not be as healthy as a normal one.

39
Q

What is a fossil

A

The remains of an organism from many years ago, which are found in a rock

40
Q

What do fossils provide evidence of

A

Evidence that organisms lived many years ago

41
Q

Explain why there is a lack of evidence to support any hypothesis about how life on earth began

A

Scientists believe many early organisms were soft bodied and tend to decay away without forming fossils plus fossils that did form would have been destroyed by geological activity (tectonic plate movement)

42
Q

Define speciation

A

Speciation is the development of a new species

43
Q

How can you tell if speciation has occurred.

A

When organisms of the same species have changed so much that they can no longer interbreed to produce fertile offspring

44
Q

Give an example of how speciation occurs through natural selection

A
  1. two populations of the same species show genetic variation due to a wide range of alleles.
  2. two populations become isolated from one another due to a physical barrier e.g. river separating primates
  3. Individual characteristics make them better adapt to their new environments and give them a better chance of survival/breeding
  4. Alleles that control the beneficial characteristics are more likely to be passed on to the next gen
45
Q

Give an example of how speciation occurs through natural selection

A
  1. two populations of the same species show genetic variation due to a wide range of alleles.
  2. two populations become isolated from one another due to a physical barrier e.g. river separating primates
  3. Individual characteristics make them better adapt to their new environments and give them a better chance of survival/breeding
  4. Alleles that control the beneficial characteristics are more likely to be passed on to the next gen
  5. eventually individuals from the different populations will have changed so much that they will not be able to breed with one another to produce fertile offspring.
  6. This means the two groups have become separate species and speciation has occurred.
46
Q

When did Russell Wallace and Charles Darwin come together publish joint work on the idea of natural selection

A

1858

47
Q

What is the name of the book that Darwin published in 1859

A

On the Origin of Species

48
Q

What prominent work is Alfred Wallace also better known for

A

His work on warning colours in animals

49
Q

Why can bacteria evolve rapidly

A

Due to their ability to reproduce rapidly

50
Q

Give examples on different types of antibiotic resistant

A 
MRSA = (Methicillin resistant Staphylococcus aures) 
MDR-TB = Multi drug resistant TB
51
Q

Why is the development of new antibiotics unlikely to keep up with the appearance of new antibiotic resistant strains of bacteria

A

The rate of development for new antibiotics is very slow which means were unlikely to be able to keep up with the demand for development of new drugs. It is also very costly to produce new drugs

52
Q

James has a mild bacterial infection and is told by his doctor that it will clear up on its own and not prescribed any antibiotics.
Suggest why James doctor does this.

A

It is important that doctors don’t over prescribe antibiotics in order to slow down the development of antibiotic resistant bacteria.

53
Q

Describe how populations of penicillin resistant bacteria may have increased

A

People may have had an infection which was treated with penicillin. A mutation may have given rise to a genetic variant which caused some bacteria to become resistant to penicillin meaning that only the non resistant strains would have been killed and the resistant bacteria would have survived and reproduced increasing their population.

54
Q

What is the Linnaean system

A

Its a system used for classifying groups of living things according to their characteristics

55
Q

How is the Linnaean system divided and further sub divided

A

Firstly divided into the Animal kingdom and Plant Kingdom then sub divided as follows:

  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species
56
Q

If you were shown the classification of an organism and asked to give its binomial name what would this be referring to

A

Every organism is named from their Genus and their Species. Binomial name would refer to the organisms Genus and Species

57
Q

What is the three domain system and who developed it

A

Is a classification system using comparisons of different organisms biochemistry and it was developed by Carl Woese

58
Q

Give a breakdown of the 3 domain system

A

The three domain system consists of:

  1. Archaea = Primitive bacteria found in extreme conditions such as hot springs
  2. True bacteria = like E coli and Staphylococcus
  3. Eukaryota = Broad range of organisms including fungi, plants animals and protists such as amoeba
59
Q

The sinaloan milk snake has evolved to have a similar pattern to the deadly coral snake. The coral snakes colour warns predators that it is dangerous to eat.
Using the idea of natural selection, explain how the milk snake may have evolved to have similar colouring to the coral snake.

A

The original milk snake showed some variation in its gene alleles which meant some had similar colouring to the coral snake and others didn’t. Milk snakes that looked like the coral snake were less likely to be eaten and so were more likely to survive, reproduce and pass on the gene specific to the coral snake colouring to the next generation of offspring.

60
Q

Darwin’s idea of natural selection were only gradually accepted. Give three reasons why this was the case.

A
  • It went against the common religious beliefs at the time
  • There wasn’t enough evidence to convince scientists at the time
  • Information regarding Genetics wasn’t known at the time
61
Q

Use your knowledge of speciation two describe how two separate species of squirrels would have formed on either side of the grand cannon.

A
  • Populations of the original squirrel species would have became separated due to the physical barrier caused by the grand cannon
  • Each population showed variation due to a wide range of alleles
  • In each population, individuals with characteristics which made them better able to adapt to their environment were more likely to survive and breed
  • The alleles specific to those characteristics would be passed down to the offspring/next generation
  • Eventually individuals from the different populations changed so much that they were no longer able to interbreed to produce fertile offspring
62
Q

A bird species is found on both sides of the grand canyon. Why would the formation of the canyon not cause the bird species to form two separate species

A

Birds have the ability to fly across the canyon so they were not isolated.

Biology Aqa Science (15 decks)

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