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H Biology > Unit 3 > Flashcards

Unit 3 Flashcards

1
Q

Definition of food security

A

the ability of a human population to access food of sufficient quality and quantity

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2
Q

Natural factors which affect food production (5)

A

drought, pests, flooding, disease, desertification

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3
Q

Damage to environment which must be avoided during food production (5)

A

global warming, pollution, deforestation, soil erosion, reducing soil fertility

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4
Q

Limiting factors of plant growth (6)

A

Light intensity, CO2 concentration, temperature, availability to nutrients, pests and diseases, competition

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5
Q

Intensive farming practices and their effects (3)

A

Growth of higher yield crops - higher yield cultivar is created or selected and maintained through cultivation
Fertilisers - give increases crop yield
Pesticides - crops are protected from pests, diseases and competition through insecticides, herbicides and fungicides

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6
Q

How is energy lost in a food chain?

A

Heat, waste and movement

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7
Q

What happens to the light that hits a leaf?

A

83% is absorbed, 12% is reflected and 5% is transmitted

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8
Q

What do the black bars on an absorption spectrum represent?

A

light wavelengths that are absorbed

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9
Q

What does an absorption spectrum show?

A

the wavelengths of light absorbed by different pigments in a leaf

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10
Q

What does an action spectrum show?

A

the rate of photosynthesis at different wavelengths of light

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11
Q

What is the function of accessory pigments?

A

to extend the range of wavelengths that can be absorbed

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12
Q

What is the first stage of photosynthesis called?

A

The light dependent stage

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13
Q

What does light energy do to electrons?

A

excites them and raises them to a higher energy state

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14
Q

What enzyme turns adp into atp?

A

ATP synthase

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15
Q

What is energy used for in the first stage of photosynthesis?

A

to phosphorylate ADP (make ATP)

photolysis of water (splitting of water into hydrogen and oxygen)

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16
Q

What does hydrogen bind to and make in the first stage of photosynthesis?

A

hydrogen binds to NADP to form NADPH

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17
Q

What is a by-product in stage 1 of photosynthesis?

A

oxygen

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18
Q

What is the second stage of photosynthesis called?

A

Carbon fixation or the calvin cycle

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19
Q

What is used in stage 2 of photosynthesis from stage 1?

A

ATP and NADPH

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20
Q

What does RuBisCO do in stage 2 of photosynthesis?

A

attach carbon dioxide to RuBP

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21
Q

What forms when carbon dioxide attaches to RuBP in stage 2 of photosynthesis?

A

3PG

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22
Q

What is 3PG used for?

A

it is phosphorylated by ATP and joins the hydrogen from NADPH to from G3P

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23
Q

How is G3P formed?

A

3GP joins with hydrogen from NADPH

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24
Q

What is G3P used for?

A

to regenerate RuBP and to synthesise glucose

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25
Q

What does the glucose produced in stage 2 of photosynthesis do?

A

some is converted into starch
some is used to produce energy in respiration
some is converted into cellulose for cell walls

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26
Q

Reasons to alter an organisms genetics (5)

A

higher yield, increase in nutritional value, resistance to disease/pests, to survive particular environmental conditions, to make it more suitable for harvesting

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27
Q

What is a cultivar?

A

a plant that has been created or selected intentionally for desirable characteristics which can be maintained through cultivation

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28
Q

What is a plant field trial?

A

an experimental investigation in an organisms natural environment instead of a lab

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29
Q

What can plant field trails evaluate? (3)

A

the performance of different cultivars in a range of environments
the effects of different treatments such as pesticides or fertilisers
genetically modified crops

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30
Q

Required when designing plant field trials

A

careful selection of treatments/variables
replicates (several trial plots increases reliability)
randomisation (where treated and controlled areas are across the plot)

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31
Q

What is inbreeding?

A

closely related plants and animals are bred for several generations until they breed true to the desired type due to the elimination of heterozygotes

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32
Q

What is inbreeding depression?

A

an accumulation of homozygous recessive alleles which can be deleterious
can result in loss of vigour, poor general health, reduced size, reduced fertility, reduced yield

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33
Q

What can inbreeding lead to? (2)

A

loss of heterozygosity

inbreeding depression

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34
Q

How are F1 hybrids produced?

A

the crossing of 2 different inbred homozygous cultivars

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35
Q

Why are the F2 generation not favourable?

A

can be too genetically diverse

can lack the improved characteristics seen in the F1

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36
Q

2 forms of genetic technology

A

genetic sequencing

genetic transformation

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37
Q

What is genome sequencing used for?

A

can be used to identify organisms that possess particular alleles for a desired characteristic

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38
Q

2 types of weeds

A

perennial

annual

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39
Q

Properties of perennial weeds (3)

A

grow for several seasons
sexual and asexual reproduction (vegetative)
storage organs

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40
Q

Properties of annual weeds (6)

A 
grow for one season only
sexual reproduction
rapid growth
short lifecycle 
high seed output
long term viability of seeds
41
Q

What are the common invertebrate pests of plants?

A

insects
nematode worms
molluscs

42
Q

What effects do invertebrate pests cause?

A

destroy the leaves
reduces the plants ability to carry out photosynthesis/ produce sugar
causes a reduction in vigour and yield of crop

43
Q

2 ways weeds, pest and diseases can be controlled

A

chemical and cultural

44
Q

3 cultural methods of crop protection

A

ploughing, weeding, crop rotation

45
Q

What is ploughing and what effect does it have?

A

turning over the top layer of soil to bury weeds deep enough for them to die and decompose

46
Q

What is weeding and what effect does it have?

A

removing weeds should be done early to reduce competion

weeds should also be removed from the edge of the field to prevent a breeding ground for pathogens

47
Q

What is crop rotation and what effect does it have?

A

a series of different crops are grown on the same piece of land one after the other over 4 growing seasons
the pathogens in the soil from the first crop cannot grow on the second

48
Q

2 chemical methods of crop protection

A

selective pesticides, systemic pesticides

49
Q

What do selective pesticides do?

A

absorbs through the leaves speeding up the metabolism of the plant so that they use up all their food reserves and die
have a greater effect on broad leaved plants

50
Q

What do systemic pesticides do?

A

spreads through the vascular system of the plant and kill pests feeding on them

51
Q

5 problems with pesticides

A

Toxicity, persistence, accumulation (bioaccumulation), magnification (biomagnification), resistant populations

52
Q

Explain toxicity (problems with pesticides)

A

pesticides can be poisonous to non-target species and could cause disease such as cancers

53
Q

Explain persistence (problems with pesticides)

A

a persistent pesticide is not broken down by the environment, harmful effects are prolonged

54
Q

Explain bioaccumulation (problems with pesticides)

A

persistent pesticides pass through food chains and build up in animal tissue, their concentration gets higher

55
Q

Explain biomagnification (problems with pesticides)

A

the concentration of persistent pesticides increases at each trophic level and can will harm the larger predators at the top of the food web

56
Q

Explain resistant populations (problems with pesticides)

A

some organisms may not be killed by the pesticide (resistant)
when they reproduce they pass on the genes for this resistance

57
Q

What is biological control?

A

the control of a pest population through the introduction of one of its ‘natural’ enemies eg predator, pathogen or parasite

58
Q

What is a problem with biological control?

A

the control organism could become invasive

59
Q

What is integrated pest management?

A

a process for controlling pests while minimising any risks to other organisms
uses a combination of chemical, cultural, and biological control to improve yield

60
Q

Advantage of IPM

A

to reduce chemical use

61
Q

Properties of intensive farming

A

cost effective
lower costs
higher profits
poorer animal welfare

62
Q

Properties of free range farming

A

requires more land
more labour intensive
gets higher price for products
better quality of life

63
Q

behavioural indicators of poor welfare

A 
stereotypy
misdirected behaviour
failure in sexual behaviour
failure in parental behaviour
altered levels of activity
64
Q

What is stereotypy?

A

where an animal makes repetitive movements over and over again
often shown by animals in bare or confined enclosures

65
Q

What is misdirected behaviour?

A

normal behaviour directed inappropriately towards itself, it’s surroundings or another animal
common in animals kept in isolation

66
Q

What is altered levels of activity?

A

animals may show very low levels of activity (apathy)
or
very high levels of activity (hysteria)

67
Q

What is direct contact? (symbiosis)

A

when a parasite is passed directly from one host to another when the two hosts come in close physical contact eg head lice

68
Q

What are resistant stages? (symbiosis)

A

some parasites can resist drying out and other stresses such as temperature extremes and harsh chemicals
they can survive outside the host for a period of time

69
Q

What are vectors? (symbiosis)

A

a vector is an intermediate organism that transfers a parasite from one host to another

70
Q

What is a secondary host? (symbiosis)

A

a secondary or intermediate host is necessary for some parasites to complete their life cycle

71
Q

What is mutualism?

A

a form of symbiosis which benefits both partner species involved in the interdependent relationship

72
Q

What is a social hierarchy?

A

a rank order within a group

73
Q

What is cooperative hunting?

A

when a group of animals work together to gain food

74
Q

Advantages of cooperative hunting (4/5)

A
  • increase in hunting excess rate
  • predators can take down larger prey
  • the kill can be made more efficiently
  • less energy is used per individual
  • all predators obtain maximum amount of food possible
75
Q

What are some social defence strategies and their benefits?

A
  • group organisation to ensure there is a lookout always available: warns group of dangers
  • groups can work together to attack a predator: protects offspring
  • animals can move together in herds, flocks or schools: more difficult for predators to pick of individuals
  • travelling in groups: provides protection for most of herd
76
Q

What is altruism?

A

a behaviour which benefits the recipient but harms the donor
common if they are related (kin)

77
Q

What is kin selection?

A

when natural selection favours behaviour that increases the survival of relatives as they share many alleles

78
Q

What is helper behaviour?

A

help in raising young usually by older offspring

79
Q

What is reciprocal altruism?

A

a type of altruism in which the roles of the donor and recipient later reverse

80
Q

What are social insects?

A

insects that exhibit social behaviours which means that they live together in large family groups and exhibit a range of complex behaviours
an example - honey bees

81
Q

What will a social insect society have? (3)

A
  • cooperative care of young insects
  • parents and their offspring living together
  • the development of a caste system
82
Q

What is ritualistic behaviour?

A

repetitive behaviours used to communicate in reproductive and competitive situations

83
Q

What is appeasement behaviour?

A

when one animal tries to reduce aggression of another through grooming, hugging or kissing

84
Q

What are the components of biodiversity that can be measured? (3)

A
  • genetic diversity
  • species diversity
  • eccosystem diversity
85
Q

What is genetic diversity?

A
  • the number and frequency of alleles within a population

- the total genetic variability/genetic characteristics of a species

86
Q

What is species diversity?

A

a measure of the number of different species in an ecosystem AND the proportion of each species

87
Q

What is species richness?

A

a measure of the number of different species in an ecosystem

88
Q

What is relative abundance?

A

the proportion of each species in an ecosystem

89
Q

What is ecosystem diversity?

A

the number of distinct ecosystems within a defined area

90
Q

What are some threats to biodiversity?

A

-overexploitation: harvesting of a natural resource

91
Q

What is the bottleneck effect?

A

when a population reduces sharply in number as a result of fire, drought, overhunting or disease
the remaining organisms may be descendants of only a small number of individuals therefore lacking genetic variation
lack of variation means the whole population is susceptible to any change in environmental conditions

92
Q

What is habitat fragmentation?

A

when a habitat is divided into several smaller habitats

93
Q

What causes habitat fragmentation?

A
  • clearing habitats for road building
  • agriculture
  • urbanisation
94
Q

What can habitat fragmentation lead to?

A

a decrease in species richness (reduced biodiversity)

95
Q

What are habitat corridors?

A

isolated fragments from habitat fragmentation can be linked
they provide a safe way to get from one place to another and increase access to food and choice of mate
eg bear bridges in banff national park

96
Q

What is an introduced species?

A

a non-native species that has arrived in a new geographical area due to human activity either intentionally or accidentally

97
Q

What is a naturalised species?

A

when a non-native species spreads within wild communities, becomes established and can maintain its population through reproduction

98
Q

What is an invasive species?

A

a naturalised species that can spread rapidly and eliminate native species therefore reducing species diversity

H Biology (3 decks)

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