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A Level - Biology > 10: Biodiversity > Flashcards

10: Biodiversity Flashcards

1
Q

What is a species?

A

The basic unit of classification

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2
Q

What do members of a species have in common?

A

They are capable of breeding to produce fertile offspring

Belong to the same gene pool

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3
Q

What is a gene pool?

A

All genes & alleles of a population

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4
Q

What do same species have in common?

A

Similar physical/biochemical
Similar immunologically (antibodies)
Occupy same ecological niche
Similar courtship behaviour

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5
Q

What is courtship behaviour determined by?

A

Genetics

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6
Q

Why can an animal with an odd number of chromosomes not reproduce?

A

Odd number of chromosomes cannot split evenly in meiosis, no gametes can form

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7
Q

What is a hierarchy?

A

Groups within larger composite groups with no overlap

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8
Q

What is the binomial naming system?

A

First generic name denotes the genus - Capital first letter
Second specific name - lowercase, if not known replaced with “sp.”
Italics in papers, underlined in exams

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9
Q

What is the purpose of courtship behaviour?

A 
Recognise members of their own species
Identify a mate capable of breeding
Form a pair bond
Synchronise mating
Become able to breed
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10
Q

Why is recognising members of the same species important?

A

Ensure mating only takes place between members of the same species
To ensure fertile offspring

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11
Q

Why is identifying a mate capable of breeding important?

A

Both partners need to be sexually mature for mating

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12
Q

How does courtship action work?

A

Male carries out a “courtship action”
Female responds yes or no
No makes male give up and moves to other female
Yes makes male do a different action and after a few this will make mating occur

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13
Q

What is the stimulus response chain?

A

Male action and response by female
Yes to actions until mating occurs
All members of same species follow same chain

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14
Q

What does courtship include?

A

Chemicals
Behavioural displays
Etc.

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15
Q

What is taxonomy?

A

Theory and practice of biological classification

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16
Q

What is artificial classification?

A

Classifies organisms according to differences based on analogous characteristics

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17
Q

What are analogous features?

A

Same function but different evolutionary origin

E.g bird wing and bee wing

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18
Q

What is phylogenetic classification?

A

Based on evolutionary relationship between organisms and their ancestors
Classifies species into groups using shared features derived from ancestors
Groups in a hierarchy

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19
Q

What are homologous characteristics?

A

Same basic structure and evolution origin but may have different functions

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20
Q

What is the domain and what are they?

A

Highest taxonomic rank

Bacteria, Archaea, Eukarya

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21
Q

What are the taxonomic ranks?

A 
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
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22
Q

What are the features of bacteria?

A 
Single-celled prokaryotes
Absence of membrane-bound organelles
Ribosomes are smaller
Cell walls contain murein
No histones
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23
Q

What are the features of archaea?

A

Single-celled prokaryotes that differ from bacteria by:
Genes/protein synthesis more similar to eukaryotes
Membranes contain fatty acids and glycerol with ether bond
No murein
More complex form of RNA polymerase

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24
Q

What are eukarya?

A

Eukaryotic cells
Membrane-bound organelles
Membranes contain fatty acids and glycerol with ester bond
Not all have cell wall, those that do have no muerin
Ribosomes are large

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25
Q

Define biodiversity

A

Variety of living organisms in an area

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26
Q

What is species diversity?

A

Refers to number of different species in one community

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27
Q

What is a community?

A

All populations of different species in a habitat

28
Q

What is genetic diversity?

A

Refers to variety of genes possessed by population of species

29
Q

What is ecosystem diversity?

A

Refers to range of different habitats

30
Q

What is local biodiversity?

A

Variety of different species in a small habitat

31
Q

What is global biodiversity?

A

Variety of different species on Earth

32
Q

What is species richness?

A

Number of different species in an area at a given time

33
Q

What is the index of diversity?

A

Way of measuring biodiversity

“d”

34
Q

What is the index of diversity equation?

A 
d = N(N-1) / sum of n(n-1)
N = number of organisms of all species
n = number of organisms of one species
35
Q

What do farmers do to affect crops and what is the affect of this?

A

Increase the amount of food that they produce

Reduces biodiversity

36
Q

What are some examples of biodiversity reduction due to agriculture?

A 
Woodland clearance
Hedgerow removal
Pesticides
Herbicides
Monoculture
37
Q

How does woodland clearance and hedgerow removal affect biodiversity?

A

Destroys habitat for farmland
Species lose shelter and food source
Causes death and loss of biodiversity

38
Q

How do pesticides and herbicides affect biodiversity?

A

They kill pests/weeds

Reduces biodiversity in the area

39
Q

What is mono-culture and how does it affect biodiversity?

A

Only grow one type of plant

Single type means supports fewer organisms

40
Q

What is done to balance biodiversity and agriculture?

A

Conservation schemes

Such as legal protection to species, or rewarding farmers for protecting biodiversity

41
Q

How can evolutionary relationships/genetic diversity be investigated?

A

Compare observable features
Compare DNA base sequences
Comparing proteins
Compare mRNA

42
Q

Why is comparing physical features done and what are the disadvantages?

A

Done as the features are due to DNA coding for structural proteins
But environment affects observable features
Observable characteristics are polygenic so there is continuous variation, difficult to make distinctions

43
Q

What does polygenic mean?

A

Characteristic is caused by many different genes

Therefore many different variations

44
Q

What are the two ways you can compare DNA base sequences?

A

DNA sequencing

DNA hybridisation

45
Q

Why is comparing DNA base sequences done?

A

Closely related species have similar DNA sequences
After evolution initially similar sequence
Over time there will be more differences due to mutations

46
Q

What is DNA sequencing?

A

Computers compare order of bases

Closely related species have a higher % of similar bases

47
Q

What colours are given to different bases in DNA sequencing?

A

Adenine - green
Thymine - red
Cytosine - blue
Guanine - yellow

48
Q

Why is mRNA sequences used to compare species?

A

mRNA copied from DNA

mRNA of a common gene can be sequenced to see how similar they are

49
Q

Why is mRNA preferable to sequencing DNA?

A

mRNA is found in the cytoplasm

mRNA is a copy of one gene not thousands of genes like in DNA

50
Q

Why is comparing proteins used to compare species?

A

Closely related species have similar amino acid sequences for the same protein

51
Q

What are the two ways to compare proteins?

A

Counting similarities/differences in amino acid sequence of the same protein in different species
Immunological comparisons

52
Q

What is immunological comparisons for comparing proteins?

A

Antibodies bind to protein to form a precipitate
Similar proteins bind to the same antibody
If antibody binds to protein in different species they are closely related
Compare amount of precipitate formed

53
Q

What is inter-specific variation?

A

Variation between different species

54
Q

What is intra-specific variation?

A

Variation between members of the same species

55
Q

Why are samples taken?

A

Unrealistic to get data from the whole population of the Earth

56
Q

Why is a sample not representative of a population?

A

Sampling bias - selection process may be biased

Chance - individuals may not be representative of the population

57
Q

What can be done to increase how representative a sample is?

A

Large sample size - smaller probability that chance will influence it and anomalies won’t affect it
Analysis - shows whether variation is the result of chance

58
Q

What is the shape of a normal distribution curve?

A

Symmetrical bell-shape

59
Q

What is it called when a distribution curve is shifted?

A

Skewed curve

60
Q

What are the three methods for calculating averages?

A

Mean - sum of values / number of values
Mode - most common value
Median - middle value of a set of values

61
Q

Where is the mean, median and mode on a normal distribution curve?

A

Same value in the middle

62
Q

What is mean used for?

A

Provides average value

Allows comparison of averages

63
Q

What is standard deviation used for?

A

Measure of spread of values around the mean

Large S.D means values vary a lot

64
Q

How is standard deviation shown on a graph?

A

Bars one standard dev. above and below

If they overlap can’t be said to be different

65
Q

Why is index of diversity used instead of species richness?

A

Takes into account both species richness and evenness
Gives an idea of the number of each species relative to population size
Small and large populations are treated differently

A Level - Biology (22 decks)

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