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A Level Biology OCR A > 4.1.2 > Flashcards

4.1.2 Flashcards

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1
Q

What is biodiversity?

A

A measure of the variation found in the living world

Biodiversity includes all different plant, animal, fungus, and microorganism species, the genes they contain, and the ecosystems they form a part of.

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2
Q

Define habitat.

A

Where an organism lives

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3
Q

What is a species?

A

A group of organisms that can freely interbreed to produce fertile offspring

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4
Q

What is habitat biodiversity?

A

The range of habitats in which different species live

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5
Q

List common habitats found in the UK.

A
  • Sand dunes
  • Woodland
  • Manicured lawns
  • Ponds
  • Dark corners between buildings
  • Small patches of trees
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6
Q

What is species biodiversity?

A

The variation among individual organisms of the same species

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7
Q

What is genetic biodiversity?

A

The variation between individuals belonging to the same species

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8
Q

Why is it difficult to count all organisms in a habitat?

A

Many microorganisms cannot be cultured, and it is impractical to count all organisms

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9
Q

What is random sampling?

A

Sample sites inside the habitat are randomly selected

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10
Q

What is an advantage of random sampling?

A

Ensures that the data are not biased by selective sampling

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11
Q

What is a disadvantage of random sampling?

A

May not cover all areas of a habitat equally and low presence species may be missed

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12
Q

Define opportunistic sampling.

A

Sampling decisions based on prior knowledge or observable characteristics

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13
Q

What is stratified sampling?

A

Dividing a habitat into areas and sampling each area separately

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14
Q

What is systematic sampling?

A

Samples are taken at fixed intervals across the habitat

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15
Q

What should be prepared before visiting a site to measure biodiversity?

A
  • Suitable clothing
  • Suitable footwear
  • Apparatus for sampling
  • Clipboard, pen, and paper
  • Appropriate identification keys
  • Camera or smartphone
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16
Q

What is a quadrat?

A

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

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17
Q

How is percentage cover estimated using a quadrat?

A

By identifying plants found within the quadrat and calculating their coverage

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18
Q

What is a transect?

A

A line taken across the habitat for sampling purposes

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19
Q

What is a pitfall trap?

A

A trap set in the soil to catch small animals

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20
Q

What is sweep netting?

A

A technique involving sweeping a net through vegetation to catch small animals

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21
Q

What is the mark-release-recapture technique?

A

A method to estimate animal population sizes by marking and releasing individuals

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22
Q

What is Simpson’s index of biodiversity?

A

A measure of the diversity of a habitat, considering species richness and evenness

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23
Q

What does species evenness measure?

A

The relative numbers or abundance of individuals in each species

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24
Q

How can abundance in plants be measured?

A

As percentage cover rather than as numbers of individuals

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25
What is the formula for calculating total population using mark-release-recapture?
Total population = (C1 x C2) / C3
26
Fill in the blank: A _______ is a version of a gene.
allele or gene variant
27
Fill in the blank: The position of a gene on a chromosome is called its _______.
locus
28
Fill in the blank: A _______ gene locus has more than two alleles.
polymorphic
29
What is necessary when estimating the size of small animal populations in soil?
Sampling soil and counting individuals
30
What is Simpson's index of diversity?
A measure of the diversity of a habitat that accounts for both species richness and species evenness ## Footnote It is calculated using the formula involving the number of individuals of a species and the total number of individuals of all species.
31
What does a high value of Simpson's index indicate?
A diverse habitat with many different species and organisms ## Footnote Such habitats can withstand environmental changes better than low-diversity habitats.
32
What is the effect of a low value for diversity in a habitat?
It suggests a habitat dominated by a few species, making it vulnerable to environmental changes ## Footnote A small change can significantly damage or destroy such a habitat.
33
How can genetic diversity be assessed?
By observing variations in observable features among individuals ## Footnote Genetic diversity is indicated by the presence of more than one allele for a particular gene locus.
34
What is a polymorphic gene locus?
A locus that has more than two alleles ## Footnote This increases genetic diversity within a population.
35
How is genetic diversity calculated?
By calculating the percentage of loci in a population that have more than one allele ## Footnote Example: Genetic diversity = (number of polymorphic loci/total loci) x 100%.
36
What is monoculture?
A crop consisting of one strain of one species ## Footnote Monocultures have very limited genetic diversity.
37
What are some human activities that affect biodiversity?
Clearing natural vegetation, habitat destruction, pollution, and overexploitation of resources ## Footnote These activities often lead to extinction and reduced genetic diversity.
38
What is the impact of agriculture on biodiversity?
It reduces the size of habitats and population sizes of wild species, leading to decreased genetic diversity ## Footnote Agriculture often relies on monoculture and selective breeding.
39
What is the significance of keystone species?
They have a disproportionate effect on their environment relative to their abundance ## Footnote Their decline can lead to dramatic changes in the ecosystem.
40
What is soil depletion?
The loss of soil fertility caused by the removal of minerals through continuous cropping ## Footnote This can lead to reduced agricultural yields.
41
What are some economic reasons to maintain biodiversity?
Ecosystem services such as regulation of climate, purification of water, and nutrient recycling ## Footnote Biodiversity supports food production and the discovery of new medicines.
42
What is conservation in situ?
Active management to maintain biodiversity in the natural environment ## Footnote It involves minimizing human impact and protecting habitats.
43
What are wildlife reserves?
Designated areas established for the conservation of habitats and species ## Footnote Large reserves are crucial for conservation efforts.
44
What are the principles for choosing a wildlife reserve?
Comprehensiveness, adequacy, and representativeness ## Footnote These ensure the long-term survival of species and ecological diversity.
45
What is the impact of climate change on species with low genetic diversity?
They show less variation and are less able to adapt to changing conditions ## Footnote They may need to migrate to suitable climates, facing various obstacles.
46
What is a major consequence of deforestation?
Increased flooding due to reduced soil protection and altered water drainage ## Footnote The removal of trees can lead to severe ecological consequences.
47
What is the current rate of extinction compared to the normal background rate?
100-1000 times higher ## Footnote Many scientists believe we are at the start of a mass extinction event caused by human activities.
48
What are marine conservation zones?
Areas of the sea set aside to conserve the diversity of species and habitats ## Footnote These zones play a critical role in protecting marine biodiversity.
49
True or False: Selective breeding increases genetic diversity.
False ## Footnote Selective breeding often reduces genetic diversity by focusing on specific traits.
50
What should conservation not mean?
Excluding all human activity
51
What needs should a reserve meet?
Needs of the indigenous people
52
What are some reasons for conflict arising in reserves?
* Protected animals raiding crops * Poaching of protected animals * Illegal harvesting of timber * Tourists feeding animals or leaving litter
53
How many National Parks are there in the UK?
15
54
What is the purpose of National Nature Reserves (NNR)?
To protect sensitive features of the environment and enable research and education
55
How many Sites of Special Scientific Interest (SSSIs) are there in the UK?
Over 6000
56
What are some examples of habitats included in SSSIs?
* Large wetlands * Chalk rivers * Heathlands * Flower-rich meadows * Shingle beaches * Upland moors and peat bogs
57
How many marine conservation zones were designated in the UK in 2013?
27
58
What are the advantages of in situ conservation?
* Conserves plants and animals in their natural environment * Protects biodiversity and ecosystems * Protects natural and cultural heritage * Allows management for ecological integrity * Provides opportunities for sustainable land uses * Facilitates scientific research * Potential to restore ecological integrity
59
What are some disadvantages of in situ conservation?
* Fragmented habitats * Loss of genetic diversity * Conditions causing endangerment may still exist * Attraction for poachers and ecotourists
60
What is repopulation in the context of biodiversity?
Rebuilding biodiversity where it has been lost
61
What is conservation ex situ?
Conservation outside the normal habitat of the species
62
What are some modern reproductive technologies used in zoos?
* Freezing sperm, eggs, or embryos * Artificial insemination * In vitro fertilisation * Embryo-transfer techniques
63
What are the advantages of ex situ conservation?
* Protection from predation and poaching * Health monitoring and medical assistance * Population division for disaster management * Measurement of genetic diversity * Selective breeding for increased diversity * Easier research on endangered species * Fundraising opportunities * Educational use
64
What are some disadvantages of ex situ conservation?
* Limited genetic diversity * Exposure to diseases * Living outside natural habitat * Nutritional management issues * Abnormal behavior and reproduction challenges * Difficulties in reintroduction to the wild
65
What is a key feature of botanic gardens in conservation?
Storage and germination of seeds
66
What technique can botanic gardens use to quickly increase plant numbers?
Tissue culture
67
What can captive-bred individuals from botanic gardens be used for?
Reintroduction to the wild

A Level Biology OCR A (2 decks)

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