Biodiversity Flashcards

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1
Q

What is a species?

A

They are capable of breeding to produce living, fertile offspring.
This means that, when a species reproduces sexually, any of the genes of its individuals can be combined with any other.

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2
Q

What was the system before the binominal naming system?

A

Scientists gave new organisms a name that described their features, e.g. blackbird, or rainbow trout.
This resulted in the same names being used in different parts of the world for very different species.
So it was difficult for scientists to be sure they were referring to the same organism.

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3
Q

What is the binominal naming system?

A

It is a universal system based upon Latin or Greek names.
The generic name denotes the genus to which the organism belongs.
The specific name denotes the species to which the organism belongs.

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4
Q

What are the rules of the binominal system?

A

The names are printed in italics or, if handwritten, they are underlined to indicate that they are scientific names.
The first letter of the generic name is in upper case, but the specific name is in lower case.
If the specific name is not known, it can be written as ‘sp.’ (in italics), for example Felix sp. (italics)

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5
Q

What is courtship behaviour?

A

Members of the same species are physically and biochemically similar and can therefore distinguish members of their own species.
The behaviour of members of the same species is more alike than that of members of different species.
Individuals can therefore recognise members of their own species by the way they act.
The ability to display a behaviour is genetically determined.
It too has evolved and it influences the chances of survival.

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6
Q

How does courtship behaviour help achieve successful mating for survival?

A

They enable individuals to:
Recognise members of their own species, to ensure mating only happens in a species, as outside offspring are infertile.
Identify a mate that is capable of breeding because both partners need to be sexually mature, fertile and receptive to mating.
Form a pair bond that will lead to successful mating and raising of offspring.
Synchronise mating so it takes place when there is maximum probability of sperm and egg meeting.
Become able to breed by bringing a member of the opposite sex into a physiological state that allows breeding to occur.

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7
Q

What happens during courtship - females?

A

The females undergo a cycle of sexual activity in which they can only conceive during a very short time.
They are often only receptive to mating for a period around the time when they produce eggs.
Courtship behaviour is used by males to determine whether the female is at this receptive stage.
If she responds with the appropriate behavioural response, courtship continues and is likely to result in the production of offspring.
If she is not receptive, she exhibits a different pattern of behaviour and the male ceases to court her, turning his attentions elsewhere.

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8
Q

What happens during courtship - chains?

A

During courtship, animals use the signals to communicate with a potential mate and with members of their own sex.
Typically there is a chain of actions between a male and a female.
The chain of actions is the same for all members of a species but differs for members of different species.
Both individuals will recognise that their partner is of the same species and that they may be prepared to mate.

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9
Q

What is classification and taxonomy?

A

Classification is organising species into more manageable groups, which allows better communication between scientists and avoids confusion.
Taxonomy is the theory and practice of biological classification.

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10
Q

What is artificial classification?

A

It divides organisms according to differences that are useful at the time.
Such features may include colour, size, number of legs, leaf shape etc.
These are described as analogous characteristics where they have the same function but not the same evolutionary origins.
For example, the wings of butterflies and birds are both used for flight but originated in different ways.

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11
Q

What is phylogenetic classification?

A

It is based upon the evolutionary relationships between organisms and their ancestors.
It classifies species into groups using shared features derived from their ancestors.
It arranges the groups into a hierarchy, in which the groups are contained within larger composite groups.

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12
Q

What are the relationships in a phylogenetic classification?

A

Relationships are partly based on homologous characteristics.
Homologous characteristics have similar evolutionary origins regardless of their functions in the adult of a species.
For example, the wing of a bird, the arm of a human and the front leg of a horse all have the same basic structure and evolutionary origins and are therefore homologous.

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13
Q

What is a taxon?

A

Each group within a phylogenetic biological classification.
Taxonomy is the study of these groups and their positions in a hierarchical order, taxonomic ranks.
These are based upon the evolutionary line of descent of the group members.

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14
Q

What is a domain?

A

The highest taxonomic rank and there are three recognised: Bacteria, Archaea (prokaryotes), and Eukarya.

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15
Q

What is bacteria?

A

A group of single-celled prokaryotes with these features:
The absence of membrane-bound organelles, nucleus and mitochondria.
Unicellular, though cells may occur in chains or clusters.
Ribosomes are smaller.
Cell walls are made of murein.
Single loop of naked DNA made up of nucleic acids, no histones.

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16
Q

What are archaea?

A

A group of single-celled prokaryotes that were originally bacteria as they resemble in appearance.
Different from bacteria because:
Genes and protein synthesis are more similar to eukaryotes.
Their membranes contain fatty acids attached to glycerol by esther linkages.
There is no murein in their cell walls.
Have a more complex form of RNA polymerase.

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17
Q

What are eukarya?

A

A group of organisms made up of one or more eukaryotic cells.
Their cells possess membrane-bound organelles.
They have membranes containing fatty acid chains attached to glycerol by ester linkages.
Not all possess a cell wall, but have no murein.
Ribosomes are larger.

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18
Q

What is the classification of Eukarya?

A

The Eukarya domain is divided into Protoctista, fungi, plantae and animalia.
Within each kingdom the largest groups are known as phyla.
Organisms in each phylum have a body plan radically different from organisms in any other.
Diversity within each phylum allows it to be divided into classes.
Each class is divided into orders of organisms that have additional features in common.
Each order is divided into families and at this level the differences are less obvious.
Each family is divided into genera and each genus into species.

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19
Q

What is phylogeny?

A

The evolutionary relationship between organisms is known as phylogeny.
The phylogenetic relationships of different species are usually represented by a tree-like diagram called a phylogenetic tree.
The oldest species is at the base of the tree while the most recent ones are represented by the ends of the branches.

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20
Q

What is biodiversity?

A

The term used to describe variety in the living world.
It refers to the number and variety of living organisms in a particular area.

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21
Q

What is species diversity?

A

The number of different species and the number of individuals of each species within any one community.

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22
Q

What is genetic diversity?

A

The variety of genes possessed by the individuals that make up of population of a species.

23
Q

What is ecosystem diversity?

A

The range of different habitats, from a small local habitat to the whole of earth.

24
Q

What is species richness?

A

A measure of species diversity.
It is the number of different species in a particular area at a given time (community).
Two communities may have the same number of species but the proportions of the community made up of each species may differ markedly.

25
Q

What is diversity index?

A

d = N(N-1) / Σn(n-1)
d = index of diversity.
N = total number of organisms of all species.
n = total number of organisms of each species.
Σ = the sum of.

26
Q

What are natural ecosystems?

A

As natural ecosystems develop over time, they become complex communities with many individuals of a large number of different species. These communities have a high index of diversity.

27
Q

What are agricultural ecosystems?

A

They are controlled by humans and are different.
Farmers often select species for particular qualities that make them more productive.
As a result, the number of species and the genetic variety of alleles they possess is reduced to the few that exhibit the desired features.

28
Q

What is the impact of agriculture?

A

To be economic, the number of individuals of these desirable species needs to be large.
Any particular area can only support a certain amount of biomass.
If most of the area is taken up by one species that the farmer considers desirable, there is only a smaller area available for all the other species.
The other species have to compete for the little space and resources available, and many will not survive this competition.
Even if species evolved to adapt to the changes, their population would be considerably reduced.

29
Q

What is the impact of pesticides?

A

Pesticides are used to exclude these species because they compete for the light, mineral ions, water and food required by the farmed species.
The overall effect is a reduction in species diversity.
The index of diversity is therefore low in agricultural ecosystems.

30
Q

How has farming affected diversity?

A

In the UK, food production has doubled in the last 40 years.
This has been achieved by the use of improved genetic varieties of plant and animal species, greater use of chemical fertilisers and pesticides, greater use of biotechnology and changes in farm practices.
This led to larger farms and the conversion of land supporting natural communities into farmland.
This has diminished the variety of habitats within ecosystems and consequently reduced species diversity.

31
Q

What practices have directly removed habitats and directly reduced species diversity?

A

Removal of hedgerows and grubbing out woodland.
Creating monocultures, for example replacing natural meadows with cereal crops of grass for silage.
Filling in ponds and draining marsh and other wetland.
Over-grading of land, for example, upland areas by sheep, preventing regeneration of woodland.

32
Q

What practices have had an indirect effect on diversity?

A

Use of pesticides and inorganic fertilisers.
Escape of effluent from silage stores and slurry tanks into water courses.
Absence of crop rotation and lack of intercropping or under sowing.

33
Q

What management techniques are there for diversity?

A

These techniques can increase species and habitat diversity, without unduly raising food costs or lowering yields.
However these practices will make food slightly more expensive to produce, and therefore to encourage farmers there are a number of financial interventions from the Department For Environment, Food and Rural Affairs (DEFRA) and the European Union.
Maintaining biodiversity is important, if it is reduced the global living system becomes increasingly unstable and we all rely on the global system for food and other resources.

34
Q

What conservation techniques are there?

A

Maintain existing hedgerows at the most beneficial height and shape. An A-shape provides better habitats than a rectangular one.
Plant hedges rather than fences as field boundaries.
Maintain existing ponds and try create new ones.
Leave wet corners of fields rather than draining them.
Plant native trees on land with a low species diversity rather than in species rich areas.
Create natural meadows and use hay rather than grasses for silage.
Leave the cutting of verges and field edges until after flowering and when seeds have dispersed.

35
Q

What conservation techniques are there - pesticides?

A

Reduce the use of pesticides - use biological control where possible or genetically modified organisms that are resistant to pests.
Use organic fertilisers.
Use crop rotation that includes nitrogen-fixing crop, rather than fertilisers, to improve soil fertility.
Use intercropping rather than herbicides to control weeds and other pests.
Introduce conservation headlands - areas at the edges of fields where pesticides are used restrictively so that wild flowers and insects can breed.

36
Q

What is comparison of observable characteristics?

A

This method is based on the fact that each characteristic is determined by a gene or genes (with environmental influences).
The variety within a characteristic depends on the number and variety of alleles of that gene.

37
Q

What are the limitations of using observable characteristics?

A

A large number of the characteristics are coded for by more than one gene - polygenic.
This means they are not discrete from one another but rather continuously, and so is often difficult to distinguish from another.
Characteristics can also be modified by the environment.
Differences may therefore be the result of different environmental conditions, rather than alleles.

38
Q

What is comparison of DNA base sequences?

A

Using gene technology, we can now read the base sequences of DNA of any organism.
The exact order of nucleotides on DNA can be accurately determined.
DNA sequencing is now routinely done by automatic machines and the data produced analysed by computers.
In these computerised systems, each nucleotide base can be tagged with a different coloured fluorescent dye - adenine green, thymine red, cytosine blue and guanine yellow.
This produces a series of coloured bands, each of which represents one of the four nucleotide bases.

39
Q

How can comparison of DNA base sequences be used?

A

We can measure the genetic diversity of a species by sampling the DNA of its members and sequencing it to produce a pattern of coloured bands.
Analysis of these patterns allows us to compare the species with another or one individual with another of the same species to determine how diverse they are.
The process would be done using the human eye and so the patterns are scanned by lasers and interpreted by computer software to give the nucleotide base sequence in a fraction of the time.
Evolutionary relationships between species can also be determined.

40
Q

What are the results of comparing DNA base sequences?

A

When one species gives rise to another species during evolution, the DNA of the new species will initially be very similar to its previous species.
Due to mutations, the sequences of nucleotide bases in the DNA of the new species will change, and over time will accumulate more and more differences in its DNA.
As a result, we would expect species that are more closely related to show more similarity in their base sequences than species that are more distantly related.

41
Q

What is comparison of the base sequence of mRNA?

A

The base sequences of mRNA are complementary to those of the strand of DNA from which they were made.
It follows that we can measure DNA diversity, and therefore genetic diversity, by comparing the base sequence of mRNA.

42
Q

What is comparison of amino acid sequence in proteins?

A

The sequence of amino acids is determined by mRNA, which is determined by DNA, so genetic diversity can be measured within and between species by comparing the amino acid sequences of proteins.
The degree of similarity in the amino acid sequence of the same protein in two species will also reflect how closely related the two species are.
Once the amino acid sequence has been determined for two species, they are compared.
This can be done by counting either the number of similarities or the number of differences in each sequence.

43
Q

What are the types of variation?

A

Interspecific variation is when one species differs from another species.
Intraspecific variation is when members of the same species differ from each other.

44
Q

What is sampling?

A

Sampling involves taking measurements of individuals, selected from the population of organisms which is being investigated.
In theory, if these individuals are representative of the population as a whole, then the measurement can be relied upon.
Sampling bias and chance can show why they are not representative however.

45
Q

What is sampling bias?

A

The selection process may be biased.
The investigators may be making unrepresentative choices, either deliberately or unwittingly.
Are they as likely to take samples of buttercups from a muddy area as a dry one?
Will they avoid areas covered in cow dung or rich in nettles?

46
Q

What is chance?

A

Even if sampling bias is avoided, the individuals chosen may, by pure chance, not be representative.
The 50 buttercups selected might just happen to be the 50 tallest in the population.

47
Q

What is random sampling?

A

To prevent sampling bias is to eliminate as much human involvement in choosing the samples as possible - random sampling:
Divide the study area into a grid of numbered lines, for example by stretching two long tape measures at right angles to each other.
Using random numbers, from a table or generated by a computer, obtain a series of coordinates.
Take samples at the intersection of each pair of coordinates

48
Q

How can chance be minimised?

A

Using a large sample size - the more individuals that are selected the smaller is the probability that chance will influence the result, and the less influence anomalies will have. If we sample only a few buttercups, there is a higher chance that they may al be taller than average, but sampling 500 has a much lower probability.
Analysis of the data collected - The data can be analysed using statistical tests to determine the extent to which chance may have influenced the data. These tests allow us to decide whether any variation observed is the result of chance or is more likely to have some other cause.

49
Q

What is the mean?

A

This is the sum of the sampled values divided by the number of items.
It is the measurement at the maximum height of the curve.
It is useful for comparing one sample with another.
However, it does not provide any information about the range of values within the sample.

50
Q

What is the mode?

A

The single value of a sample that occurs most often.

51
Q

What is the median?

A

This is the central or middle value of a set of values.
This requires arranging the values in ascending order.

52
Q

What is standard deviation?

A

The measure of the width of the curve. It gives an indication of the range of values either side of the mean.
A standard deviation is the distance from the mean to the point where the curve changes from being convex to concave.

53
Q

What is the equation for standard deviation?

A

Standard deviation = √Σ(x-x̄)^2 / n-1
Σ = the sum of.
x = measured value (from sample).
x̄ = mean value.
n = total number of values in the sample.