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GCSE - Biology > Biology Higher 4 GCSE (only B4 and B5) > Flashcards

Biology Higher 4 GCSE (only B4 and B5) Flashcards

1
Q

define an ecosystem

A

the living and physical conditions in an area

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2
Q

define a community

A

the organisms within an ecosystem

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3
Q

define a habitat

A

the area in which a community lives

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4
Q

define population

A

the total number of organisms in an area

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5
Q

producers

A

plants and organisms that can make up their own food.

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6
Q

consumers

A

they are unable to make their own food and have to eat producers to gain energy

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7
Q

decomposers

A

they gain energy by breaking down dead or decaying material.

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8
Q

biotic factors

A

living factors

like number of trees, squirrels etc.

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9
Q

abiotic factors

A

non-living factors

like light intensity, temperature, pH, moisture level.

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10
Q

what is competition

A

when animals compete fr limited resources

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11
Q

what do animals need

A 
food
water
breeding partner
space
shelter
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12
Q

what do plants need

A 
light 
water
carbon dioxide
minerals 
space
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13
Q

3 types of interdependance

A

predation
mutualism
parasitism

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14
Q

how may energy be lost between trophic levels

A

not all of the organism is eaten
some of the biomass may be used in respiration, which produces ATP for movement and heat
Indigestible parts of an animal- hair, nails
waste products

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15
Q

efficiency of biomass transfer

A

efficiency of biomass transfer=

biomass after transfer/ biomass before transfer *100

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16
Q

how does nitrogen go from the air to plants

A

nitrogen-fixing bacteria that mix oxygen with nitrogen in the air to make nitrates

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17
Q

how does ammonia in the soil get absorbed by plants

A

nitrifying bacteria turns ammonia into nitrates

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18
Q

how do nitrates turn back into nitrogen in the atmosphere

A

denitrifying bacteria releases nitrogen

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19
Q

what is percolation

A

when water trickles through soils and rocks to join the river

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20
Q

why do the levels of carbon dioxide vary during the day

A

photosynthesis only takes place during the day- so co2 in only removed during the daylight
respiration happens 24/7 so co2 is continued to be added the entire day

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21
Q

whats the difference between a decomposer and a detritivore

A

decomposers are microorganisms. they break down or decay organic material at a microscopic level.
detritivores are small animals that speed up decomposition by breaking down organic material into smaller pieces.

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22
Q

how do bacteria release nutrients

A

they release enzymes on the dead remains
the enzymes can then digest the dead matter and make it soluble (dissolve-able)
the soluble products are absorbed by the fungus

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23
Q

what factors affect the rate of decomposition

A

warm temperatures
Moist environments: needs water to decompose
aerobic conditions: oxygen is needed for the microorganisms to respire.

24
Q

rate of decay

A

rate of decay = change in mass (g)/ time (day)

25
Q

phenotype

A

the appearance of an organism

26
Q

what is variation

A

difference within a species

27
Q

genetic variation and environmental variation

A

genetic- physical genetic material in an organism (dna)

environmental- the environment in which you live in

28
Q

discontinuous variation

A

individuals that show characteristics that fall into distinct groups, such as blood groups

29
Q

continuous variation

A

can have any value between minimum and maximum

30
Q

asexual reproduction

A 
usually produces clones
examples: 
potato plants 
spider plants 
daffodils
31
Q

sexual reproduction

A

requires 2 parents
its offspring isn’t identical since it uses 2 pair of genes
it produces sex cells called gametes that fuse together in fertilisation.

32
Q

advantages and disadvantages of asexual reproduction

A

advatages:
if the parent can adapt well to an area, so can the offspring
only one parent is needed- so its quicker to reproduce

disadvantage:
if there is a change to biotic or abiotic changes, it may destroy the entire species

33
Q

advantages and disadvantages of sexual reproduction

A

advantage:
variation in offspring leads to adaptations in a species

disadvantage:
reproduction requires 2 parents. It is much slower so fewer offspring are produced

34
Q

differences between diploid and haploid cells

A

diploid: 46 chromosomes
haploid: 23 chromosomes

35
Q

what is a zygote

A

a fertilised egg cell

36
Q

meiosis

A

produces gametes

which are haploid cells (23)

37
Q

chromosomes for male

A

XY

38
Q

chromosomes for female

A

XX

39
Q

history of genetics

A

1866- Gregor Mendel carried out an experiment on peas
He noticed that characteristics were determined by hereditary units (now called genes)
They are passed on from both parents and they are either dominant or recessive

1869- Nuclein discovered
Friedrich Miescher discovered there is an acidic substance present in each nucleus (DNA)

1944- Genes can be transferred from one generation to another

1950- DNA base pairs found by Erwin Chargaff

1952- DNA crystals photographed by Maurice Wilkins and Rosalind Franklin

1953- Double helix structure
James Watson and Francis Crick

1953- 2000 - Identified individual genes that code for genetically inherited disorders

2003- Human genome project completed- they discovered 24000 genes

40
Q

evolution

A

a gradual change in species over time

41
Q

explain natural selection

A
  1. Organisms show variation caused by a difference in their genes
  2. The organisms with the characteristics that are best adapted will survive
  3. genes from the successful will be passed down to their offspring
  4. the process is then repeated many times
42
Q

examples of evolution

A

peppered moths-
before the industrial revolution, moths were pale. then a mutation made them dark coloured, but they didn’t survive because they couldn’t camouflage against the light coloured trees
after the industrial revolution, the trees were covered in soot so they became dark and the darker moths became more camouflaged against them, so they survived longer

43
Q

how are fossils made

A
  1. the reptile dies
  2. the flesh rots, leaving the skeleton covered in sand and soil before it is damaged
  3. protected over millions of years, it becomes mineralised and turns to rock
  4. eventually, the fossils emerge as the rocks move and erosion takes place
44
Q

how does the fossil record provide evidence for evolution

A

fossils of the simple organisms are generally much older compared to the more complex ones that are much younger
plant fossils appear before animal ones- so animals clearly needed plants
closely related organisms came from the same ancestor and this can be found by studying their anatomy

45
Q

what other evidence is there for evolution

A

rapid change in species- as bacteria can replicate, scientists can study evolution in action and observe the changes
extinction- species that are unable to adapt to environmental changes usually die out
molecular comparison- scientists have began to compare the DNA and proteins of different species and the order of nucleic orders etc.

46
Q

Theory of evolution

A

He joined a scientific expedition to the Galapogas Islands and he made his observation on finches. He saw that the beaks of the finches was entirely based on the types of food that they ate.
At the same time that Charles Darwin was developing his theory, Alfred Russel Wallace gathered evidence for his theory, which was overall very similar to Darwin’s so they did a joint report.

47
Q

Binomial nomenclature

A

A universal system of naming species.
The first name is the organism’s genus.
The second name is the organism’s actual name

48
Q

Classification system

A 
Kingdom 
Phylum 
Class
Order 
Family 
Genus 
Species
49
Q

Natural classification

A

looking for a common ancestor. the study of evolutionary links is known as phylogeny.

50
Q

artificial classification

A

they group together organisms based off of their physical, observable characteristics.

51
Q

define a species

A

a group of organisms that share the same genetic material and can breed to have fertile offspring

52
Q

A research team want to genetically engineer pigs so that they produce organs that are not
rejected by humans.
Describe how they could do this

A 
Identify gene for human tissue types 
isolate this gene 
insert this gene into the pig embryo 
replicate the gene
check the cell for expression of the gene
53
Q

how is malaria spread

A

an example of protozoa
mosquitoes suck blood out of someone with malaria
then pass it on

54
Q

what happens to a person’s lungs when they are having an asthma attack

A

airways become swollen and restrict air flow.

muscles around bronchiols contract

55
Q

why is the ozone layer reducing

A

people using CFCs, refrigeration

greenhouse gases increased

GCSE - Biology (28 decks)

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