Biodiversity and classification Flashcards
What is classification
The organisation of living organisms into groups
What is a species
A group of organisms that are capable of breeding to produce living, fertile offspring.
What is the binomial system
The system we use to name organisms where they are given two names- The first is called the generic name and the second is the specific name.
What does the generic name in the binomial system for classifying organisms tell us
The generic name denotes the genus to which the species belongs.
What does the specific name in the binomial system for classifying organisms tell us
The specific name denotes the species to which organisms belong.
What are the key three rules that are applied to the binomial system in scientific writing
1) The names are printed in italics, or, if handwritten, they are underlined to indicate that they are scientific names.
2) The first letter of the generic name is in uppercase, but the first letter of the specific name is in lowercase.
3) if the specific name is not known it can be written as ‘sp’
What is the purpose of courtship behaviour
To ensure that mating is successful and that the offspring have the maximum chance of survival.
How does courtship behaviour help to achieve its purpose of ensuring that mating is successful and the offspring have the maximum chance of survival.
- individuals can recognise members of their own species
- individuals can identify a mate that is capable of breeding.
- individuals can from a pair bond
- Individuals can synchronise mating
- individuals become available to breed by bringing s member of the opposite sex into a physiological state that allows breeding to occur.
How is individuals being able to recognise a member of their own species an advantage of courtship behaviour
It ensures that mating only takes place between members of the same species because only members of the same species can produce fertile offspring.
How is individuals being able to identify a mate that is capable of breeding an advantage of courtship behaviour
It is important because both partners need to be sexually mature, fertile and receptive to mating.
How is individuals being able to form a park bond an advantage of courtship behaviour
Forming a pair bond leads to successful mating and raising of the offspring.
How is individuals being able to synchronise mating an advantage of courtship behaviour
Individuals synchronise mating so that it takes place when there is the maximum probability of the sperm and egg meeting.
What is taxonomy
The theory and practice of biological classification
What are the two main forms of biological classification
1) Artificial classification
2) Phylogenetic classification
What is artificial classification
- Artificial classification divides organisms according to differences that are useful at the time.
- Such features may include colour, size, number of leg etc.
- These are described as analogous characteristics where they have the same function but do not have the same evolutionary origins.
What is an example of an analogous characteristic that may be used in artificial classification
Wings of butterflies and birds- they are both used for flight but originated in different ways.
Describe phylogenetic classification
Phylogenetic classification:
A) Is based upon the evolutionary relationships between organisms and their ancestors
B) classifies species into groups using shared features derived from their ancestors.
C) Arranges the groups into a hierarchy, in which the groups are contained within larger composite groups with no overlap.
What are relationships in a phylogenetic classification partly based on?
Homologous characteristics
What are homologous characteristics
Homologous characteristics have similar evolutionary origins regardless of their functions in the adult of a species.
What is each group in the phylogenetic classification called
A taxon (plura taxa)
What is a domain
- A domain is the highest taxonomic rank.
What are the three recognised domains
- Bacteria
- Archaea
- Eukarya
Describe the domain of bacteria
- Bacteria are a group of single-celled prokaryotes with the following features:
1) The absence of membrane-bound organelles such as nuclei or mitochondria
2) Unicellular, although cells may occur in chains or clusters.
3) Ribosomes are smaller (70S) than in eukaryotic cells
4) Cell walls are present and made of murein (but never chitin or cellulose)
5) Single loop of naked DNA made up of nucleic acids but no histones.
Describe the domain of archaea
- Archaea are a group of single-celled prokaryotes that were originally classified as bacteria which they resemble in appearance.
- They differ from bacteria because:
1) Their genes and protein synthesis are more similar to eukaryotes.
2) Their membranes contain fatty acid chains attached to glycerol by ether linkages.
3) There is no murein in their cell walls.
4) They have a more complex form of RNA polymerase.
Describe the domain of eukarya
- Eukarya are a group of organisms made up of one or more eukaryotic cells.
- Their features are:
1) Their cells possess membrane-bound organelles such as mitochondria or chloroplasts.
2) They have membranes containing fatty acid chains attached to glycerol by ester linkages.
3) Not all possess cells with a cell wall, but where they do it contains no murein.
4) Ribosomes are larger (80S) than in bacteria and archaea
What are the four kingdoms that the Eukarya domain is divided into
- Protoctista
- Fungi
- Plantae
- Animalia
List the order of classification in the Linean system
1) Domain
2) Kingdom
3) Phylum
4) Class
5) Order
6) Family
7) Genus
8) Species
Define phylogeny
The evolutionary relationship between organisms.
What is biodiversity
The general term used to describe variety in the living world.
What are the three components of biodiversity
1) Species diversity
2) Genetic diversity
3) Ecosystem diversity
What is species diversity
Species diversity refers to the number of different species and the number of individuals of each species within any one community.
What is genetic diversity
Genetic diversity refers to the variety of genes possessed by the individuals that make up a population of species.
What is ecosystem diversity
Ecosystem diversity refers to the range of different habitats, from a small local habitat to the whole of the earth.
What is one of the ways of measuring species diversity
Species richness
What is species richness
The number of different species in a particular area at a given time.
What is the calculation we use to measure biodiversity called
The index of species diversity.
Will agricultural ecosystems have a high or low species diversity.
Low
List some of the factors that have led to food production doubling in the UK over the past forty years
Improved genetic varieties of plant and animal species, greater use of chemical fertilisers and pesticides, greater use of biotechnology and changes in farm practices which all lead to larger farms and the conversion of land supporting natural communities into farmland.
List some of the agricultural practices that have directly removed habitats and reduced species diversity
- removal of hedgerows and grubbing out woodland
- creating monocultures, for example replacing natural meadows with cereal crops or grass for silage.
- Filling in ponds and draining marsh and other wetland.
- over-grazing of land, for example upland areas by sheep, thereby preventing regeneration of woodland.
List some of the agricultural practices that have indirectly led to a decrease in biodiversity
- 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 undersowing.
List 12 examples of conservation techniques that farmers can use
1) Maintain existing hedgerows at the most beneficial height and shape. An A-shape provides better habitats than a rectangular one.
2) Plant hedges rather than erect fences as field boundaries.
3) Maintain existing ponds and here possible create new ones.
4) Leave wet corners of fields rather than draining them.
5) Plant native trees on land with a low species diversity rather than in species-rich areas.
6) Reduce the use of pesticides- use biological control where possible or genetically modified organisms that are resistant to pests.
7) use organic, rather than inorganic, fertilisers.
8) use a crop rotation that includes a nitrogen-fixing crop, rather than fertilisers, to improve soil fertility.
9) Use intercropping rather than herbicides to control weeds and other pests.
10) create natural meadows and use hay rather than grasses for silage
11) Leave the cutting of verges and field edges until after flowering and when seeds have dispersed.
12) Introduce conservation headlands- areas at the edges of fields where pesticides are used restrictively so that wildflowers and insects can breed.
List the four key ways which genetic diversity can be compared between organisms
1) Comparison of observable characteristics
2) Comparison of DNA base sequences
3) Comparison of the base sequence of mRNA
4) Comparison of amino acid sequences in proteins.
Describe the comparison of observable characteristics method of looking at genetic diversity
- This method is based on the fact that each observable 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 (plus environmental influences)
What is the limitation with using comparison of observable characteristics as a method of looking at genetic diversity
- Most characteristics are coded for by more than one gene- they are polygenic.
- This means that they are not discrete from each other but vary continuously.
- it is often difficult to distinguish one from another.
- characteristics can also be modified by the environment so differences differences may be because of different environmental conditions not different alleles.
Why can we measure genetic diversity by comparing base sequences of mRNA
- mRNA is coded for by DNA as the base sequences on mRNA are complementary to the DNA it was made from.
- Therefore, comparing base sequences of mRNA works in the same way comparing DNA does.
Why can we use the comparison of amino acid sequences in proteins as a method of measuring genetic diversity
- the sequence of amino acids in proteins is detained by mRNA, which is determined by DNA.
- the degree of similarity in the amino acid sequence of the same protein in two species therefore reflects how closely related they are.
What is interspecific variation
Two species differing from one another
What is intraspecific variation
Members of the same species differing from one another.
What is sampling
- 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 populations as a whole, then the measurements can be relied upon.
What are two key reasons why measurements taking when sampling might not be representative of the population.
1) sampling bias: The selection process may be biased. The investigators may be making unrepresentative choices.
2) Chance: Even if sampling bias is avoided, the idnividuals choose, by chance, may not be representative.
Why is random sampling a good way of sampling
It eliminates sampling bias
Describe a method of random sampling to stop sampling bias.
1) Divide the study area into a grid of numbered lines, for example, by stretching two long tape measures at right angles to each other.
2) Using random numbers, from a table or generated by a computer, to obtain a series of coordinates
3) take samples at the intersection of each pair of coordinates.
What can you do to aim to remove chance from the sampling process
- Use a large sample size: The more individuals that are selected, the smaller the probability is that chance will influence the result, and the less influence anomalies will have.
- analyse in depth the data collected
What three values are associated with a normal distribution curve
- the mean
- the mode
- the median
How does the mean appear on a normal distribution curve
- the mean is the measurement at the maximum height of the curve/peak of the curve.
How is the standard deviation shown on a normal distribution curve
- the standard deviation is a measure of the width of a 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.
