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BIOLOGY GCSE > INHERITANCE, VARIATION AND EVOLUTION #2 > Flashcards

INHERITANCE, VARIATION AND EVOLUTION #2 Flashcards

1
Q

what are the two factors that influence some of our characteristics

A

genes and environment

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2
Q

natural selection

A

start with variation is present in the population due to mutations
the change in conditions (in the question) causes the (mutation) to become an advantage
this means the individuals with the mutation are more likely to survive, breed and pass on the allele for that characteristic to their offspring
the offspring inherit the characteristic
the change in condition must be sustained over multiple generations

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3
Q

what is selective breeding

A

selective breeding is a process where humans breed plants and animals for desired characteristics

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4
Q

what type of features is selective breeding used for to acquire

A

disease resistance in food crops or garden plants
animals that produce more meat or milk
domestic dogs and farm animals with a gentle nature
large flowers

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5
Q

the process of selective breeding

A

from existing stock select the ones that have the characteristics you are after
breed them with each other
select the best of the offspring and breed them together
continue this process over several generations, eventually all the offspring will have the characteristics

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6
Q

limitations of selective breeding

A

selective breeding greatly reduces the number of alleles in the population
there is less variation between individuals in the population

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7
Q

what is genetic engineering

A

is to transfer a gene responsible for a desirable characteristic from one organism into another organism so that it also has that characteristic

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8
Q

process of genetic engineering

A

a useful gene is cut from the chromosome of an organism using enzymes and is inserted into a vector
the gene is then inserted into the chromosome of another organism
this gives it its desirable characteristic

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9
Q

how can insulin be made so that patients do not have to use pig insulin

A

the gene for insulin production is cut from human dna using enzymes
a bacterial plasmid is cut open with enzymes and the human gene inserted
the plasmids are transferred to bacterial cells which then produce the insulin by protein synthesis

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10
Q

how are gm crops useful

A

they have had their genes modified to improve the size
quality of fruit
or to make them resistant to disease

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11
Q

problem with genetic engineering

A

maybe changing the organisms genes might accidently create unplanned problems which could get passed on to future generations

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12
Q

cons for gm crops

A

may not be safe for human health

transplanted genes can get out into the natural environment

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13
Q

pros for gm crops

A

certain characteristics can increase the yield

people living in developing countries lack nutrients, gm crops could be engineered to contain the nutrients missing.

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14
Q

what are clones

A

clones are individuals that are identical to their parents

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15
Q

how to clone plants

A

tissue culture- take small groups of cells from part of a plant and growing them under special conditions
a mass of identical plant cells form called a callus
each callus cell can be grown into a new plant

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16
Q

name a quick and cheap way of cloning plants

A

tissue culture

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17
Q

two ways of cloning animals

A

embryo transplant and adult cell cloning

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18
Q

what happens in embryonic cloning

A

an embryo is divided into several individual cells
each cell grows into an individual embryo in the lab
transfer embryos into their host mothers, which have been given hormones to get them ready for pregnancy
identical cloned calves are born

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19
Q

in adult cell cloning…….

A

you remove the nucleus from an unfertilised egg cell,
take the nucleus from a skin cell and insert it into an empty egg cell
give the cell an electric shock so it starts to divide to form an embryo
insert the embryo into a host mother to develop

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20
Q

benefits of adult cell cloning

A

save animals from extinction

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21
Q

risks of adult cell cloning

A

limits the variation in a population

ethical reasons

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22
Q

benefits of genetic engineering in medicine and agriculture

A

medical drugs have been produced
gm crops have been developed that they are resistant to herbicides or to insects
other gm crops grow well in hot places in the world
can improve the growth rate of plants and animals

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23
Q

disadvantages of genetic engineering in medicine and agriculture

A

insects that are not pests may be affected by gm crops
in the long terms insects may become resistant to pesticides
worry about the effect of eating gm crops on human health

   ethical reasons
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24
Q

what two factors cause variation between organisms of the same type

A

genes

the environment

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25
Q

in adult cell cloning which cell provides the nucleus for the clone

A

a skin cell from the adult being cloned

26
Q

how are new genes formed

A

by mutation

27
Q

what class of chemicals is used to stimulate the cells in tissue culture

A

hormones

28
Q

for natural selection questions what should you remember

A

mutation of gene—-advantage to survival——-breed——pass on genes

29
Q

lamaraks theory

A

his theory stated that characteristics that develop during an organisms lifetime can be passed on to the next generation

30
Q

darwins theory

A

theory of natural selection when he went to an island

he noticed that organisms of a particular species show a wide range of variation for a particular characteristic

he also observed that reproduction always gives more offspring than the environment can support

he concluded that those with characteristics best suited for their environment are more likely to survive and breed successfully
Darwin did not know about genes

31
Q

why did people object darwins theory of evolution

A

it challenged the creationist theory that god created the earth and all living things on it
many scientists were not convinced because they still did not think there was sufficient evidence for the theory
Darwin theory could not be explained without the knowledge of genetics and variation which was discovered 50 years after darwins death

32
Q

what is speciation

A

where the populations become so different that successful interbreeding is no longer possible

33
Q

what is genetic variation

A

the wide range of alleles that control the characteristics in a population

34
Q

what is isolation

A

where two populations of a species become separated

35
Q

how can populations become isolated

A

islands can break away from mainland new rivers can form mountain ranges can separate populations and climate

36
Q

what are fossils

A

fossils are the remains of organisms from millions of years ago that can be found in rocks

37
Q

how can fossils be formed

A

from the hard parts of animals that do not decay easily
from parts of organisms that have not decayed because some conditions for decay are absent
parts of organisms being replaced by other materials

38
Q

name a hard part of an animal that will not decay easily

A

bones

39
Q

what is extinction

A

means that a species that once existed has completely died out

40
Q

what can cause extinction

A

a new disease can kill all members of a species
a new predator may be introduced to an area that kills and eats all species
a catastrophic event can happen like a volcanic eruption

41
Q

why might a species die out if the climate changes

A

climate change may make it too cold or hot or too wet or too dry for a species and reduce its food supply

42
Q

why do some pathogens spread rapidly

A

people are not immune to it

there is no effective treatment

43
Q

what do mutations of pathogens produce

A

new strains that are resistant to antibiotics

44
Q

how does antibiotic resistant bacteria become resistant

A

mutations of pathogens new strains which are resistant to antibiotics
antibiotics kill the individual pathogens that have not developed resistance
the resistant pathogens survive and reproduce and a whole population of a resistant strain develops

45
Q

how do you slow down the rate of development of resistant strains

A

antibiotics should not be used for mild infections and patients should always complete each course of antibiotics

46
Q

what are the three domains called

A

archaea, bacteria and eukaryota

47
Q

what is archaea

A

they are primitive forms of bacteria, including extremophiles that can live in extreme conditions

48
Q

what kingdom does the domain archaea have

A

archaebacteria

49
Q

what kingdom does the domain bacteria have

A

eubacteria

50
Q

what is eukaryota

A

all have cells that contain a nucleus enclosing the genetic material

51
Q

what kingdoms do eukaryota have

A

Protista
fungi
plants
animals

52
Q

why are there no fossils of early life forms

A

early organisms had soft bodies so any fossils would’ve been destroyed by geological activity

53
Q

MRSA Is a bacterium resistant to many antibiotic how can the spread be reduced in hospitals

A

doctors and nurses should wash hands to kill microorganisms
isolate patients to reduce spread of bacteria
make sure visitors wash their hands before and after they leave the hospital to maintain high amount of hygiene

54
Q

suggest three factors that can change in a habitat area causing problems for the organisms living there

A

the climate might change hot colder wetter drier
a new predator might move into the area
a new competitor for the food supply might move into the area

55
Q

what is the main difference between lamaraks theory of evolution and darwins theory

A

Lamarck suggested that characteristics that developed during the lifetime of the organism could be passed on, Darwin said that organisms with the best characteristic survived to breed and the offspring inherited the characteristic

56
Q

what are evolution trees

A

they show the relationship between different groups of organisms

57
Q

what is geographical isolation give an example

A

two populations of organisms become separated and live in two different regions for example either side of a river

58
Q

what are the stages of speciation

A

isolation of two groups
there is genetic variation in the two populations
alleles are selected that give an advantage
interbreeding is no longer possible because the populations have diverged
therefore a new species has formed

59
Q

types of genetic testing

A

antenatal testing
neonatal testing
pre- implantation genetic diagnosis

60
Q

antenatal testing

A

Antenatal testing is used to analyse an individual’s DNA or chromosomes before they are born. This testing is offered to couples who may have an increased risk of producing a baby with an inherited disorder, but it can’t detect all the risks of inherited disorders.

61
Q

neonatal testing

A

involves analysing a sample of blood that is taken from pricking a baby’s heel. It detects genetic disorders in order to treat them early.

62
Q

Pre-implantation genetic diagnosis (PGD)

A

is used on embryos before implantation. Fertility drugs stimulate the release of several eggs.The eggs are collected and fertilised in a Petri dish. This is known as in vitro fertilisation (IVF). Once the embryos have reached the eight-cell stage, one cell is removed.

BIOLOGY GCSE (15 decks)

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