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Biology > Unit 2.3 Biodiversity And Evolution > Flashcards

Unit 2.3 Biodiversity And Evolution Flashcards

1
Q

What is a species?

A

A group of individual organisms very similar in appearance, anatomy, physiology, biochemistry and genetics, whose members are able to interbreed freely to produce fertile offspring

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2
Q

What is a habitat?

A

The place where an organism lives

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3
Q

What is biodiversity?

A

The variety of life - the range of living organisms to be found

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4
Q

What is genetic variation?

A

Variation between individuals belonging to the same species

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5
Q

What is random sampling?

A

Studying a small part of the habitat and assuming it contains a representative set of species that can be applied to the whole habitat. The sample sites must be chosen at random

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6
Q

Name 2 ways of randomly choosing the position of a sample site

A
  • Take samples at regular distances across the habitat
  • Use random numbers, generated by a computer or a random number table, to plot coordinates within the habitat
  • Select coordinates from a map of the area and use a portable global positioning satellite system to find the exact position inside the habitat
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7
Q

How many samples should you take?

A

Depends on the size of the habitat and the time available

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8
Q

Why is the random sampling technique not always good for counting plants?

A

Can miss plants that occur only infrequently

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9
Q

What is a quadrat?

A

A square frame used to define the size of the sample area

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10
Q

How can you measure the abundance of plants within a quadrat?

A
  • An abundance scale, such as ACFOR (abundant, common, frequent, occasional, rare)
  • Estimate the percentage cover (using a point frame - a frame holding a number of long needles or pointers)
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11
Q

What is a transect?

A

A line taken across the habitat

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12
Q

What is the difference between a line and a belt transect?

A

Line: record the plants touching the line at set intervals along it; could use a quadrat at set intervals along the line (interrupted line transect)
Belt: place a quadrat beside the one and move it along to line so you can study a band or belt in detail

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13
Q

What is the problem with sampling animals?

A

They move - any attempt to sample the animals in a habitat will disturb the habitat, so many animals will detect your presence and hide away.
Should not trap larger animals; can note their presence by careful observation

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14
Q

What are 4 methods of catching animals?

A

Sweep netting, collecting from trees, a pitfall trap, a Tullgren funnel, a light trap

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15
Q

Why do we need to study a habitat?

A
  • Human activities affect the environment in a number of ways
  • Unless we study how our activities affect our environment, we cannot assess the effect we have
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16
Q

What is species richness? How can you measure it?

A

The number of species present in a habitat.

Use a qualitative survey - make observations within the habitat and record all the different species you see.

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17
Q

What is species evenness?

A

A measure of the relative numbers or abundance of individuals in each species

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18
Q

How can you measure species evenness of plants?

A

Count the number of plants of each species per unit area, or measure the percentage cover of each species

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19
Q

How can you measure species evenness of animals?

A

Calculate how many animals of each species there are per unit area of the habitat

  • Larger animals: observe carefully and count the individuals present
  • Smaller animals: take samples, then calculate population size using the mark-and-recapture technique
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20
Q

How does mark-and-recapture work?

A
  • Capture a sample of animals, then mark each individual in some way that causes it no harm. The number captured will be C1.
  • Then release them and leave the traps for another period of time
  • The number captured on the 2nd occasion will be C2
  • The number of already marked animals will be C3
    Total population = (C1 x C2)/C3
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21
Q

What is Sinpson’s Index of Biodiversity?

A

A measure of the diversity of a habitat, that takes into account both species richness and species evenness.
Formula: D = 1 - Σ(n/N)^2
n is the number of individuals of a particular species
N is the total number of all individuals of all species
High value = a diverse habitat

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22
Q

What are the 5 kingdoms? Briefly describe each.

A

Prokaryotes: have no nucleus
Fungi: consist of a mycelium with walls made from chitin
Plants: multicellular organisms that gain their nutrition from photosynthesis
Animals: heterotrophic multicellular eukaryotes
Protoctists: include all the organisms that don’t fit into the other 4 kingdoms

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23
Q

What is the difference between autotrophs and heterotrophs?

A

Autotrophs: gain their nutrition from photosynthesis
Heterotrophs: gain their nutrition by digesting and absorbing organic matter

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24
Q

Name 3 features of prokaryotes

A
  • No nucleus
  • Have a loop of naked DNA that is not arranged in linear chromosomes
  • Have no membrane-bound organelles
  • Have smaller ribosomes than in other groups
  • Have cells smaller than those of eukaryotes
  • May be free-living or parasitic
  • Carry out respiration on cell surface membranes
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25
Q

Name 3 features of protoctists

A
  • Eukaryotes
  • Mostly single called
  • Show a wide variety of forms
  • Show various plant-like or animal-like features
  • Mostly free-living
  • Have autotrophic or heterotrophic nutrition
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26
Q

Name 3 features of fungi

A
  • Eukaryotes
  • Have a mycelium, which consists of hyphae
  • Have walls made of chitin
  • Have cytoplasm that is multinucleate
  • Mostly free-living and saprotrophic (cause decay of organic matter)
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27
Q

Name 3 features of plants

A
  • Eukaryotes
  • Multicellular
  • Have cells surrounded by a cellulose cell wall
  • Have autotrophic nutrition
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28
Q

Name 3 features of animals

A
  • Eukaryotes
  • Multicellular
  • Have heterotrophic nutrition
  • Have fertilised eggs that develop into a ball of cells called blastula
  • High degree of mobility
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29
Q

Why do we classify living things?

A
  • For our convenience
  • To make the study of living things more manageable
  • To make it easier to identify organisms
  • To help us see the relationships between species
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30
Q

What is the current system of classification?

A

There are 8 taxa:

  • Domain
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species
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31
Q

What is taxonomy?

A

The study of the principles behind classification

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32
Q

What are the 3 domains for classification?

A
  • Bacteria (eubacteria)
  • Archaea (archaebacteria)
  • Eukaryotae
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33
Q

What is the binomial system?

A

A system that uses 2 names to identify each species:

- The genus name and the species name

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34
Q

Why is the binomial system good?

A
  • Latin is used as a universal language in the binomial system
  • So whenever a species is named, it is given a universal name
  • Every scientist in every country will use the same name
  • This avoids the potential confusion caused by using common names
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35
Q

When writing the name of an organism, what should you do?

A
  • Put it in italics if typed, or underline it if handwritten

- Use a capital letter for the first letter of the genus name

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36
Q

Why should you carry out an environmental impact assessment (EIA) before carrying out a large development?

A

To check that the development will not harm the environment too much

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37
Q

Why is it important to identify organisms when developing on a site?

A
  • When carrying out an EIA, scientists need to know what species are present in the area
  • If there is a species that is very rare, then losing that habitat would have a major impact on that species and on the environment
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38
Q

What is a dichotomous key?

A
  • A way of identifying and naming a specimen you have found
  • It uses a series of questions with 2 alternative answers
  • The answer to each question leads you to another question
  • Eventually the answers will lead you to the name of the specimen
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39
Q

What is physiology?

A

The study of how living things work

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40
Q

How can biochemistry be used for classification?

A
  • Evidence from biochemistry can help to determine how closely related 1 species is to another
  • Certain large biochemical molecules are found in all living things, but they may not be identical in all living things
  • The differences reflect the evolutionary relationships
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41
Q

How can cytochrome c be used to help classify species?

A
  • This protein is used in the process of respiration, but it is not identical in all species
  • Proteins are large molecules made from a chain of smaller units called amino acids
  • The amino acids in cytochrome c can be identified
  • If we compare the sequence of amino acids in samples of cytochrome c from 2 different species, we can draw certain conclusions:
    • If the sequences are the same, the 2 species must be closely related
    • If the sequences are different, the 2 species are not so closely related
    • The more differences found between the sequences, the less closely related the 2 species
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42
Q

How can DNA be used to classify species?

A

All organisms use DNA or RNA.
DNA always provides the genetic code, which means that a particular piece of DNA or RNA codes for the same protein in a bacterium as in any other organism.
- DNA sequences can be compared
- The more similar the sequence, the more closely related the 2 species are

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43
Q

What are some structural differences between Bacteria and Archaea/Eukaryotae?

A

Bacteria have:

  • A different cell membrane structure
  • Flagella with a different internal structure
  • Different enzymes for building RNA
  • No proteins bound to their genetic material
  • Different mechanisms for DNA replication and building RNA
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44
Q

What features do Archaea share with the Eukaryotae?

A
  • Similar enzymes for building RNA
  • Similar mechanisms for DNA replication and building RNA
  • Production of some proteins that bind to their DNA
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45
Q

What is variation?

A

The presence of differences between individuals

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46
Q

How is genetic variation caused?

A

By differences between the genes and the combination of genes or alleles

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47
Q

What are the 2 forms of variation within a species?

A
  • Continuous

- Discontinuous

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48
Q

What is continuous variation?

A
  • Variation in which there is a full range of intermediate phenotypes (values) between 2 extremes
  • Most individuals are close to the mean value
  • The number of individuals at the extremes is low
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49
Q

What is discontinuous variation?

A
  • Variation in which there are discrete groups of phenotypes with no or very few individuals in between
  • The members of a species may be evenly distributed between the different forms, or there may be more of 1 type than the other
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50
Q

What is environmental variation?

A
  • Variation caused by the environment, such as diet.

- Not all our genes are active at 1 time, but changes in the environment affect which genes are active

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51
Q

How are environmental variation and genetic variation linked?

A

Environmental variation is limited by your genes

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52
Q

What is an adaptation?

A

A feature that enhances survival and long-term reproductive success

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53
Q

What are the different types of adaptations that an organism can have?

A
  • Behavioural
  • Physiological/biochemical - ensures the correct functioning of cell processes
  • Anatomical - a structural adaptation
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54
Q

What are xerophytic plants?

A

Plants that are adapted to living in very dry conditions

55
Q

What behavioural adaptations do xerophytic plants have? Explain they help to reduce water loss.

A
  • Some close their stomata when little water is available, which conserves water so that they do not wilt
  • Some open their stomata only at night, which conserves water because less will be lost from the leaves at night when it is cooler and the air is more humid
  • Some fold or roll their leaves when water is in short supply. This traps moist air in the folded leaves, so it reduces the water vapour potential gradient for diffusion out of the leaf, reducing water loss
  • Some open their stomata when they are short of water, which causes the leaves to wilt and exposes less surface area to the sun
56
Q

What physiological/behavioural adaptations do xerophytic plants have?

A

The mechanisms by which a plant can open or close its stomata, fold its leaves or store water

57
Q

What anatomical adaptations do xerophytic plants have?

A
  • The roots may be shallow, but spread out over a wide area, allowing a plant to absorb a lot of water when it is available
  • The roots may be very long, enabling the plant to reach water that is deep underground
  • The stem or leaves may be fleshy (an adaptation to store water)
  • The leaves may be reduced in size, reducing the surface area for evaporation
  • The leaves may be very waxy, so moisture can leave the leaf only through the stomata
  • The leaves may be curled, folded, hairy, or have their stomata sunk in pits. These adaptations trap a layer of moist air next to the stomata, reducing the water potential gradient for water vapour to diffuse into the atmosphere, reducing water loss by transpiration.
58
Q

Why people be concerned about using insecticides?

A

Insects develop insecticide resistance.
Harm unintented species.
Ethically wrong.

59
Q

Suggest how the effects of insecticide can be measured.

A

Randomly sample areas before and after insecticide is used, using a sweet net technique. Sample at different times of day, and have at least 5 samples. Use the same technique of counting the insects. Use the capture-recapture technique.
Calculate the mean.

60
Q

Define variation

A

Differences within a species

61
Q

Suggest why a small mass range of a species may not be accurate

A

Only a small number have been sampled, individuals sampled may not be representative and individuals sampled from one area may be different from average of the whole population

62
Q

What are the advantages of using a seed bank, opposed to adult plants, to conserve a plant specises?

A 
Seeds can be collected from the wild without damaging habitat.
Plants produce an excess of seeds.
They can stored for a long time.
They take up little space.
Store large numbers.
Cheaper to transport.
63
Q

Why is it important seeds are collected from different sites in the wild for a seed bank?

A

Increase gene pool.
Reduced chance of disease affecting whole population.
Reduces chance of inbreeding.
Maintain geographical variation.

64
Q

Suggest why antibiotic resistance is a major concern.

A

Have untreatable illnesses.
Potential pandemic.
Developing new antibiotics is expensive

65
Q

How does fossil evidence support the idea that evolution has taken place?

A

Fossils show organisms have changed over time.
Fossils can be dated.
Fossils show intermediate forms.

66
Q

What is natural selection?

A

The selection by the environment of particular individuals that show certain variations. These individuals will survive to reproduce and pass on their variations to the next generation.

67
Q

What is speciation?

A

The formation of a new species

68
Q

How long does speciation take?

A

It generally takes many generations, because it is a long, slow accumulation of changes

69
Q

How does speciation occur?

A

There must be a reproductive barrier, so that some organisms are unable to breed with others in the group:

  • Variations or changes that provide a benefit spread down the generations in a population through reproduction
  • If changes occur in part of the group, but cannot spread to the whole group, then only part of the group will benefit
  • A collection of small changes that cannot pass to the whole group means that some members become different to the rest
  • They may become so different that they can no longer interbreed
70
Q

What is allopatric speciation?

A

Speciation due to organisms of a species being separated by geographical barriers so that over time members of the 2 populations become so different that they cannot interbreed and are considered to be 2 different species

71
Q

What is sympatric speciation?

A

Speciation that occurs within one area - some factor other than geographical separation has prevented free interbreeding between members of the species

72
Q

Outline the features of domain classification compared with the 5 kingdom system
(3 marks)

A

Based on DNA
Domain divides into kingdoms.
Domain reflects differences between bacteria and archaea such as DNA replication
Eukaryote domains are grouped from kingdoms Protoctists, plants, animals, and fungi - they all have nucleus’s.
Prokaryotes are in the same kingdom

73
Q

Describes the different forms of variation

7 marks

A

Continuous - effect of many genes
Quantiative - range of intermediate values
Discontinuous - few genes with no environmental effect and no intermediates

74
Q

Explain why a reduction in biodiversity may present problems for agriculture in the future

A

Loss of genetic diversity and genes, so lose gene for resistance to disease.
We don’t know what crops will be needed in the future.

75
Q

Suggest how the excessive use of inorganic fertilisers on farmland can cause a reduction in biodiversity.

A

They promote the growth of one species. Other plants are out competed.

76
Q

Explain why it may become more difficult to discover new drugs in the future.
(2 marks)

A

Habitats destroyed due to deforestation.
Drugs from these plants.
Biodiversity is reducing.

77
Q

State the properties of collagen. (2 marks)

A

Strong, flexible and not elastic

78
Q

A student places his quadrat on areas he considers to have the most biodiversity. How is this wrong? (2 marks)

A

Unrepresentative data
Not random
Over - estimate of biodiversity

79
Q

Define the term classification. (2 marks)

A

Placing organisms into groups based on similarities.

80
Q

Explain three aspects of a development (motorway) that would need to be considered when carrying out an EIA (3 marks)

A

The biodiversity of the ecosystem.
If there are endangered species present.
Rarity of habitat.
Current legal status eg National Park.

81
Q

Explain why two species share the same genus name.

A

They have a similar appearance.

They have a common ancestor.

82
Q

Explain why animals are taken from different areas for ex-situ conservation. (3 marks)

A

To increase genetic biodiversity.
Reduce risk of inbreeding.
Geographical variation.
Less risk to lose to disease.

83
Q

Explain how fungus adapts to overcome a resistance of a plant to it. (4 marks).

A

Resistance is the selection pressure. Those fungus that are suspeptable are killed but the fungus that overcome the resistance due to a random mutuation causing genetic variation, survive. They reproduce passing on their characteristics to their offspring.

84
Q

What were the observations that Darwin made, that led to his theory of evolution?

A
  • Offspring generally appear similar to their parents
  • No two individuals are identical
  • Organisms have the ability to produce large numbers of offspring
  • Populations in nature tend to remain fairly stable in size
85
Q

Summarise Darwin’s conclusions

A
  • There is a struggle to survive
  • Better adapted individuals survive and pass on their characteristics
  • Over time, a number of changes may give rise to a new species
86
Q

What is the problem with fossil evidence?

A

There are gaps in the record, so it is incomplete:

  • Usually only the hard parts of an organism survive to become a fossil
  • Many living things don’t have any hard parts, so they leave no fossils
  • Also fossils only form under certain conditions
  • After they have formed, they can still be damaged or destroyed by movements of the rocks
87
Q

How can the study of biological molecules provide evidence for evolution?

A

If one species gives rise to another, both are likely to have the same biological molecules

  • Certain molecules are found throughout the living world
  • 2 closely related species will have evolved recently as separate species, so the biological molecules in each are likely to be identical or similar
  • In species that took separate evolutionary paths a long time ago, the biological molecules are likely to differ more
88
Q

How can protein variation provide evidence for evolution?

A

Vital proteins such as DNA polymerase and RNA polymerase are found in all living things
- The central part of these proteins is very similar across all living groups
- Higher organisms have added extra subunits, which do not affect the basic function of the enzyme but they appear to improve the regulation of its action
Cytochrome c
- The sequence of amino acids in cytochrome c can be compared
- The number of changes is greater for species that are very different

89
Q

How can the structure of DNA provide evidence for evolution?

A
  • Genes can be compared by sequencing the bases in DNA

- This shows that closely related species evolved relatively recently as separate species

90
Q

How can a species evolve into a new, different species?

A
  • A population of the species migrates to a new environment
  • An environmental change affects only some populations of the species
  • There is a reproductive barrier preventing some populations of the species from interbreeding
91
Q

What are insecticides?

A

Pesticides that are designed to kill insects

92
Q

How do insecticides work?

A
  • It applies a very strong selection pressure
  • If the individual insect is susceptible, it will die
  • If it has some form of resistance, the individual will survive
  • This will allow it to reproduce and pass on the resistance characteristic
  • So the resistance quickly spreads through the whole population
93
Q

How has resistance to insecticides developed?

A
  • The insects may be able to break down the insecticide using enzymes (they metabolise them)
  • The target receptor protein on the cell membrane may be modified
94
Q

How can pesticides become a problem for the food chain?

A
  • If insects are resistant, they survive applications of these chemicals
  • The insects may then be eaten by their predators
  • The predators receive a larger dose of the insecticide
  • It is quite possible for the insecticide to move all the way up the food chain
95
Q

How can bacteria become resistant to antibiotics?

A
  • When you take antibiotics, most of the bacteria are killed
  • But there may be one, or a few, that are resistant to the antibiotic
  • They are rarely completely unaffected by the antibiotic, but they are more resistant than most
  • Once most of the bacteria have been killed, you tend to feel better, so many people stop taking the antibiotics before they have finished the prescribed course
  • This allows the resistant bacteria to survive and reproduce to create a resistant strain of bacteria
  • Overuse and incorrect use of antibiotics has led to strains of bacteria resistant to virtually all the antibiotics in use
96
Q

How has human society developed in recent centuries?

A
  • We have learned to use the environment to our advantage
  • Our numbers have risen dramatically and continue to rise
  • We are using more and more of the Earth’s resources
  • Our activities often harm other species, either directly or indirectly
  • Loss of biodiversity occurs
  • Extinction may occur
97
Q

What is extinction?

A

When a species ceases to exist

98
Q

Name some human activities that reduce biodiversity and cause extinction

A
  • Hunting for food (over-harvesting)
  • Killing for protection (e.g. Insects that are vectors of disease)
  • Killing to remove other competitors for our food (e.g. Use of pesticides to kill insects, fungi and other pests)
  • Pollution
  • Habitat destruction (e.g. Deforestation)
  • Inadvertent introduction of new predators and competitors to natural flora and fauna
99
Q

Why is it important to conserve the diversity of species alive today?

A

Evolution has provided answers to many technological problems
Natural ecosystems perform processes that are of value to humans:
- Regulation of the atmosphere and climate
- Purification and retention of fresh water
- Formation and fertilisation of soil
- Recycling of nutrients
- Detoxification and recycling of wastes
- Crop pollination
- Growth of timber, food and fuel
All living organisms have the right to survive and to live in the way for which they have become adapted

100
Q

What are the threats to a species with low genetic diversity?

A
  • Changes in the climate
  • Increase in levels of pollution
  • Emergence of new diseases
  • Arrival of new pests
101
Q

Why is genetic diversity important?

A

It makes it possible for a species to evolve, because they can adapt to changes in the environment

102
Q

What is the gene pool?

A

The sum total and variety of all the genes in a population or species at a given time

103
Q

How do humans affect the genetic diversity of natural habitats through habitat destruction?

A
  • When we clear natural vegetation, we reduce the size of natural habitats and reduce the population size of any species living in those habitats
  • This reduces the overall gene pool for the species
  • This decreases the genetic variation and hence the ability of the species to evolve
104
Q

How can modern agriculture affect genetic variation?

A

It uses monoculture and selective breeding:

  • This reduces the variation and genetic diversity of domesticated plants and animals
  • It also leads to the extinction of some varieties within a species
105
Q

What is genetic erosion?

A

The loss of genetic variation due to (artificial) selection or habitat loss

106
Q

Why is climate change a big problem for species that have lost their genetic variation?

A
  • They are unable to evolve
  • As the climate changes, they will be unable to adapt to the changes in temperature and rainfall in the area where they live
  • The only alternative will be for them to move
  • Plant and animal populations can move with changing conditions
107
Q

What obstructions are there to the migration of plants/animals?

A
  • Major human developments
  • Agricultural land
  • Large bodies of water
  • Humans
108
Q

How can global warming affect agriculture?

A
  • Higher carbon dioxide levels altering photosynthesis
  • Higher temperatures increasing growth rate
  • Longer growing seasons
  • Greater evaporation of water and therefore greater precipitation
  • A change in the distribution of precipitation
  • Loss of land due to rise in sea level and increased salinity of soil
109
Q

How can diseases be affected by climate change?

A
  • Crops being grown in new areas will encounter new diseases and pests
  • Higher temperatures may provide a longer growing season for crops, but the pests will also have more time in which to increase in numbers
  • More species of pests and diseases may be able to overwinter successfully and cause greater infestations earlier in the year
    Human diseases will also migrate
110
Q

Why is it important to conserve biodiversity?

A

If biodiversity declines, then genetic diversity will also decline
- This means at we could lose the natural solution to some of our problem
Wild animals and plants may hold the answers to problems caused by climate change:
- Populations of wild pants growing in an area have had thousands of years to evolve
- They have adapted to overcome the problems presented by the environment
- They may also have adapted to the pests and diseases found in that area
- By careful selection and breeding from wild species, we may be able to breed new crop varieties that can cope with the new conditions created by climate change
The number of potential new medicines to be found in wild plants is unknown
The range of possible vaccines that could be developed from wild microorganisms is also unknown

111
Q

What is conservation in situ?

A

The conservation of a species within its normal environment

112
Q

Why is conservation in situ important?

A

It minimises human impact on the natural environment and protecting the natural environment

113
Q

What are the advantages of designating an area as a reserve?

A
  • Plants and animals are conserved in their natural environment
  • It permanently protects biodiversity and representative examples of ecosystems
  • It permanently protects significant elements of natural and cultural heritage
  • It allows management of these areas to ensure that ecological integrity is maintained
  • It provides opportunities for ecologically sustainable land uses, including traditional heritage activities and the associated economic benefits
  • It facilitates scientific research
  • It may be possible to restore the ecological integrity of the area
114
Q

What conflict has arisen due to reserves being set up without consideration of the local people?

A
  • Protected animals coming out of the reserve to raid crops
  • People continuing to hunt protected animals for food
  • Illegal harvesting of timber and other plant products
  • Tourists feeding protected animals or leaving litter
115
Q

What is conservation ex situ?

A

The conservation of an endangered species by activities that take place outside its natural environment

116
Q

What are the advantages of conservation ex situ?

A
  • It can increase the numbers of individuals in an endangered species
  • It can also enable repopulation by introducing captive-bred animals to the wild
117
Q

What are the disadvantages to captive breeding?

A
  • Expensive
  • The animals are often not in their natural environment and many animals fail to breed successfully
  • Space is limited and this limits the number of individuals, which restricts the genetic diversity
  • A decrease in the genetic diversity of a population results in a lack of variation
  • This means the species is less able to adapt to changing conditions, which can affect animals’ ability to breed successfully
  • Even if reproduction is successful the animals have to survive reintroduction to the wild, where they need to find food and survive predation
  • There can also be difficulties with acceptance by the existing wild members of their species
118
Q

What modern techniques are there that make it possible to preserve large amounts of genetic material?

A
  • Sperm freezing
  • IVF
  • Artificial insemination
  • Embryo-transfer
119
Q

How can plants be conserved?

A
  • As part of their life cycle, most plants naturally have a dormant stage (the seed)
  • As seeds are produced in large numbers, they can be collected from the wild without causing too much disturbance to the ecosystem or damaging the wild population
  • These seeds can be stored in huge numbers (they don’t take up much space) and germinated in protected surroundings
  • Plants can often be bred asexually
  • The botanical garden can increase the numbers of individuals very quickly, providing an ample supply of individuals for research
  • The captive-bred individuals can be replanted in the wild
120
Q

What are the disadvantages of conserving plants using seeds?

A
  • Any collection of wild seeds will cause some disturbance
  • The collected samples may not hold a representative selection of genetic diversity
  • Seeds collected from the same species from another area will be genetically different and may not succeed in a different area
  • Seeds stored for any length of time may not be viable
  • Plants bred asexually will be genetically identical, reducing genetic diversity further
  • Conclusions from research based on a small sample may not be valid for the whole species
121
Q

What is a seed bank?

A

A collection of seed samples

122
Q

What are the advantages of seed banks?

A
  • They contain seeds that can remain viable for decades and possibly hundreds of years
  • The seeds are not simply being stored
  • Some of them are being used to provide a wide range of benefits to humanity:
    • food and building materials for rural communities
    • disease-resistant crops for agriculture
  • They can also be used for habitat reclamation and repopulation
123
Q

How are seeds stored?

A

In very dry or freezing conditions:

  • they are resistant to desiccation
  • the level of moisture in each has a direct effect on storage
  • for every 1% decrease in seed moisture level, the life span doubles
  • for every 5% reduction in temperature, the life span also doubles
124
Q

Why are germination tests needed?

A

To ensure that stored seeds have not died and are able to germinate

125
Q

How do seed banks carry out germination tests?

A
  • They ‘plant’ the seeds in Petri dishes of nutrient agar and keep them in controlled conditions
  • Scientists measure the germination rate (% of seeds that germinate) and the success of germination
  • This enables scientists to monitor the condition of the stored seeds
126
Q

What does CITES stand for?

A

The Convention on International Trade in Endangered Species of Wild Fauna and Flora

127
Q

What does CITES aim to do?

A
  • Regulate and monitor international trade in selected species of plants and animals
  • Ensure that international trade does not endanger the survival of populations in the wild
  • Ensure that trade in wild plants in prohibited for commercial use
  • Ensure that trade in artificially propagated plants is allowed, subject to permit
  • Ensure that some slightly less endangered wild species may be traded subject to a permit, as agreed between the exporting and importing countries
128
Q

What are the aims of The Convention on Biological Diversity?

A
  • Conservation of biological diversity
  • Sustainable use of its components
  • Appropriate shared access to genetic resources
  • Appropriate sharing and transfer of scientific knowledge and technologies
  • Fair and equitable sharing of the benefits arising out of the use of genetic resources
129
Q

What is an environmental impact assessment?

A

A procedure to assess the likely significant effects that a proposed development may have on the environment

130
Q

What are the reasons for carrying out an EIA?

A
  • Avoid or minimise any significant adverse affects on the biological diversity of an area
  • Ensure that any potential environmental consequences of a development are taken into account
  • Promote the exchange of information, consultation + notification of any development that might affect another partner state
  • Promote the notification of any grave danger or damage to biological diversity that may affect another partner state
  • Promote arrangements for emergency responses to activities or events that present a grave and imminent danger to biological diversity
131
Q

What criteria is used to determine whether an EIA is needed?

A
  • Size of the development
  • Environmental sensitivity of the location
  • Types of impact expected
132
Q

What are the 3 broad stages of an EIA?

A
  • The developer compiles an environmental statement, which includes an assessment of local biodiversity and the effect the development is likely to have on biodiversity
  • The environmental statement is publicised
  • The authority takes it into account when making a planning decision
133
Q

How does evolution occur?

A
  • Variation must occur before evolution can take place
  • There is a random genetic mutation
  • Once variety exists, then the environment can ‘select’. It will select those variations that give an advantage
  • Individuals with an advantage will survive and reproduce
  • Therefore they pass on their advantageous characteristics (inheritance)
  • The next generation will be better adapted to their environment. Over time, the group of organisms becomes well adapted to its environment (adaptation)

Biology (3 decks)

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