biodiversity Flashcards

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1
Q

Define a species

A

A species is a group of organisms with similar phenotypes, which can breed to produce fertile offspring

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2
Q

Outline how species are named

A

Species are named using a binomial system, having a generic name (the genus) and a specific name (the species).

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3
Q

Describe courtship behaviour and explain its purpose

A

Courtship behaviour includes: displays, signals, gift bringing, calls. It helps animals to: recognise members of the same species, identify a mate that is capable of breeding, form a pair bond, synchronise mating, stimulate a physiological state to allow breeding.

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4
Q

Explain the principles of classification

A

Phylogentic classification groups organisms based on evolutionary relationships, shared features derived from ancestors and arrnages groups into a hierachy of decreasing size and there is no overlap between groups. It follows the system: domain, kingdom, phylum, class, order, family, genus, species.

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5
Q

Explain the relationship between classification and evolution

A

Phylogenetic classification is based on characteristics which have the same evolutionary origins. Taxa are based on evolutionary line of descent. The highest taxonomic group is the domain which comprises Bacteria, Archae and Eukarya.

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6
Q

Describe the meaning of species diversity

A

The number of species and the number of individuals of each species within a community

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7
Q

Explain how a diversity index can be used

A

Species diversity index is a quantitative method of measuring species diversity. It takes into account both measures of species diversity, and enables a comparison to be made between different sites or the same site at different times. This can be useful in assessing the success of habitat management techniques.

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8
Q

Describe the effect of agriculture on species diversity and the species diversity index

A

Selective breeding leads to reduced allele frequency, so reduced genetic diversity. Creation of monocultures and the use of pesticides to reduce competition between pest species and the crop species reduce the species diversity index in an area.

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9
Q

Describe specific agricultural activities which reduce species diveristy, include direct and indirect examples.

A

Removal of hedgerows and grubbing out of woodland, filling in ponds and draining wetlands, over grazing, use of pesticides and inorganic fertilisers, espace of effluent from silage stores and slurry tanks in to water courses, absence of crop rotation and lack of intercropping or undersowing.

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10
Q

Explain how a balance between conservation and farming can be achieved

A

Maintain existing hedgerows or plant new ones, maintain ponds and wetland or create new areas. Reduce pesticide use, use biological control measures instead, use organic fertilisers, use crop rotations using nitrogen fixing plants, use intercropping to control weeds and pests, create meadows, don’t cut road vergs until after seed dispersal, introduce conservation headlands to encourage breeding of insects and wild flowers.

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11
Q

Explain the use of the following techniques in comparing genetic diversity within, and between, species:- Observable characteristics

A

This is an historic method of comparing genetic diversity and is based on the assumption that observable characteristics are coded for by genes. Variation within the characteristics corresponds to the number of and variety of alleles. This is unreliable due to polygenic characteristics, and environmental factors affecting observable characteristics.

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12
Q

Base sequence of DNA

A

Nucleotide bases can be tagged by dyes. This enables comparison of base sequences between organisms by computers. This can also be used to determine evolutionary relationships.

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13
Q

Base sequence of mRNA

A

As mRNA bases are complementary to DNA, sequencing mRNA can give the same information as that of DNA

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14
Q

Amino acid sequence of proteins

A

Since amino acid sequences are determined by mRNA which is determined by DNA, it can give a measure of genetic diversity. Amino acid sequences for proteins in different organisms can be compared. More similarities means closer evolutionary relationships.

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15
Q

Explain how immunological comparisons are used to investigate variations in proteins

A

Antibodies of one species will respond to specific antigens on proteins in the blood serum of another species. Serum from species A is injected into species B. Species B produces antibodies specific to the antigen sites on protein from species A. Serum is extracted from species Band mixed with the blood of species C. The antibodies respond to the corresponding antigens on the protein of species C. This forms a precipitate. Mre similar antigens leads to more precipitate being produced, and therefore indicates the two species (B & C) are closely related.

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16
Q

Describe how random sampling carried out.

A

Random sampling is used to estimate populations or choose individuals to study from a population. Divide your study area into a grid. Use a random number generator to give co-ordinates. At each co-ordinate place a quadrat or select an individual to study. Record the number of target organisms in each quadrat. Or record the characteristics of the selected individual.

17
Q

Explain what sampling is and why it is used.

A

Sampling is when measures are taken of a selection of individuals and the findings are extrapolated to give a measurement for a whole population. It would be impossible to count the number of red blood cells in a human body, but a small sample can be taken and an estimate can be made using the results. Sampling can be random to avoid sampling bias, however, chance can cause some individuals which are not representative of the population to be included which can cause results to be unreliable.

18
Q

Describe the types of variation and their causes

A

Interspecific variation is the differences between species and is the result of evolution by natural selection. Intraspecific variation is the differences between individuals of the same species and is caused by different alleles, including new alleles caused by mutations and by environmental factors.

19
Q

Explain what is meant by the mean and standard deviation

A

The mean is the sum of the sampled values divided by the number of samples. It is always the highest point of a normal distribution curve. Standard deviation is a measure of the range of values from the mean. It gives an indication of the variance within the data set.

20
Q

What is meant by the term ‘species richness’?

A

the number of different species in a particular area at a given time

21
Q

Why is it more useful to calculate species diversity, rather than relying on species richness?

A

It measures number of species AND the number of individuals. Some species may only be present in small numbers

22
Q

What is meant by the term ‘biodiversity’?

A

the range and variety of alleles, species and habitats within a specific region

23
Q

How does the diversity of agricultural land differ from that of a natural ecosystem?

A

agricultural land is controlled by humans.
There is a smaller number of species and a smaller variety of alleles.
Large amounts of species considered valuable reduce the space and nutrients available for other species

24
Q

Give 3 farming practices that directly reduce species diversity

A

removal of hedgerows
creating of mono-cultures
filling in ponds/draining other wetlands
over-grazing of land –> preventing regeneration of woodland

25
Q

Give 3 farming practices that indirectly reduce species diversity

A

use of pesticides/inorganic fertilisers
escape of effluent from silage stores
absence of crop rotation and lack of inter-cropping

26
Q

Give 5 examples of conservation techniques to reduce the impacts of farming practices

A

plant hedges as field boundaries
reduce pesticide use/ use organic fertilisers
use inter-cropping to control weeds
maintain existing ponds
leave wet corners of fields

27
Q

What are 4 ways of investigating genetic/bio diversity?

A

comparing observable characteristics
comparing DNA base sequence
comparing mRNA base sequence
comparing a/a sequence in proteins

28
Q

Give 3 limitations of comparing observable characteristics as a way of measuring diversity

A

large numbers of observable characteristics are coded for by more than one gene
difficult to distinguish
Characteristics can be modified by the environment

29
Q

What is interspecific variation?

A

differences in organisms from two different species

30
Q

What is intraspecific variation?

A

members of the same species differ from one another

31
Q

Why may sampling not be an accurate representation of a population

A

sampling bias
chance

32
Q

Give 2 ways we can minimise the risk of chance impacting the sampling process

A

bigger sample size
analysis of the data collected

33
Q

Why is taking a larger sampling size good?

A

reduce impact of anomalies
reduce risk of chance
increases reliability

34
Q

Why might biomass be used rather than the number of individuals?

A

individual organisms too small to count/could not be identified

35
Q

Why use sterilised soil when investigating plants?

A

kill pathogens that cause disease
no other fungi/bacteria
no competitors