10. Biodiversity Flashcards
Define biodiversity
The range and variety of genes, species and habitats within a particular region.
Define species diversity
The number of different species and the number of individuals of each species within any one community.
Define genetic diversity
Variety of alleles possessed by the individuals within a population of a species.
Define ecosystem diversity
The range of different habitats within an ecosystem.
Define species
A group of similar organisms that can breed together to produce fertile offspring.
Define classification
The organisation of living organisms into groups, based on accepting principles
Name the system of naming species
Binomial system
Name and describe the 2 parts of the binomial system.
- The generic name: denotes the genus
- The specific name: denotes the species.
What are the rules of the binomial system?
- Names printed in italics/underlined if handwritten
- First letter of generic name in capitals, specific name in lower case.
- If specific name unknown, written as ‘sp’, e.g. Felix sp
Why is it crucial that mating is successful?
The females of most species only produce eggs at specific times, often as little as once a year. Courtship behaviour determines when the female is in the receptive stage.
Why do members of the same species display the same behaviour?
Because they have the same/similar genes.
How does courtship behaviour help increase the chance of successful mating.
- Recognise members of their own species to ensure that mating can produce fertile offspring.
- Identify a mate capable of breeding because both partners need to be sexually mature, fertile and receptive to mating.
- Form a pair bond that leads to successful mating and raising of offspring.
- Synchronise mating so that it takes place where max probability of sperm and egg meeting.
- Become able to breed by bringing members of opposite sex into a physiological state that allows breeding to occur.
Define taxonomy
Taxonomy is the study of phylogenetic groups (taxa) and their positions in a hierarchical order, where they’re known as taxonomic ranks, based on an evolutionary line of descent of the group members.
What is artificial classification?
Divides organisms according to differences useful at the time, Features include analogous characteristics such as colour, size etc. Have same function but not the same evolutionary origins.
What is phylogenetic classification?
- Based upon evolutionary relationships between organisms and their ancestors.
- Classifies species into groups using shared features derived from ancestors.
- Arranges groups into a hierarchy
Define hierrarchy
Groups contained within larger, composite groups with no overlap.
What is the highest taxonomic rank?
Domain
What are the 3 domains?
Bacteria, Archaea and Eukarya
Give features of Bacteria
- Single celled prokaryotes
- Absence of membrane bound organelles
- Unicellular
- Ribosomes smaller than eukaryotes, 70s
- Cell walls made of murein
- Single loop of naked DNA, made up of nucleic acids but no histones
Give features of Archaea
- Single celled prokaryotes
- Cells possess membrane-bound organelles
- Have membranes containing fatty acid chains attached to glycerol by ester bonds
- No murein in cell walls
- More complex RNA polymerase than bacteria
Give features of Eukarya
- Cells possess membrane-bound organelles
- Have membranes containing fatty acid chains linked to glycerol by ester bonds
- Not all cells have cell wall, but ones that do never contain murein
- Ribosomes larger than bacteria, archaea, 80s
- Divided into 4 kingdoms: Protoctista, Fungi, Plantae and Animalia.
Give the classification order
Domain Kingdom Phylum Class Order Family Genus Species
Suggest a way in which the courtship behaviour of one species might be used to determine which of the other 2 species are most closely related to it.
The courtship display that most closely resembles that of the first species is likely to be the closest relative.
Define species richness
The number of different species in a community.
What is the equation for calculating the index of diversity
d = N(N - 1) /
{n(n - 1)
d= index of diversity N= total number of organisms of all species n= total number of organisms of each species
What piece of information do you need to have to calculate the index of diversity?
Total number of organisms of each species
Explain why it is more useful to calculate a species diversity index than just to record the number of species present?
It measures both the number of species and the number of individuals in each species. It therefore takes into account species only present in small numbers.
Explain how agriculture has reduced species diversity
The few species possessing desirable characteristics/alleles are selected and bred. Other species are excluded, as far as possible, by the use of culling or the use of pesticides. Many individuals of a few species, causes low species diversity Therefore, unlike natural ecosystems, agricultural ecosystems have a low index of species diversity.
Explain the balance between conservation and farming
Population growth has caused a great pressure on intensive farming of food. This is achieved by use of genetic varieties of species, chemical fertilisers and pesticides and biotechnology. However, intensive food production has diminished the variety of habitats and reduced species diversity.
Explain why there’ s a reduction in species diversity when a forest is replaced by grassland for grazing cattle
Because forests, with their many layers, contain many habitats with many different species, so have high species diversity. Grasslands have a single layer, fewer habitats, fewer species and low species diversity.
Suggest why the draining of ponds on agricultural land might have a greater effect on biodiversity than removing a hedgerow
Ponds provide a habitat for a wide range of aquatic species that are unlikely to find alternative habitats as aquatic habitats are few and distanced. Ponds may be a source of food and water for terrestrial species which may not survive without them. Hedgerow species are likely to have a wider range of alternative habitats as most of the areas will be terrestrial with other sources of food and shelter so fewer species lost
Give examples of conservation techniques
- Maintaining hedgerows at beneficial height and shape
- Maintain existing ponds, create new ones
- Leave wet corners of field
- Plant native trees on land of low species diversity
- Reduce use of pesticides
- Use organic fertilisers
Why is measuring observable characteristics a poor measure of genetic diversity?
- A large number of characteristics are coded for by more than one gene, so they’re not discrete and vary continuously. It’s therefore hard to distinguish between one another.
- Characteristics can be modified by the environment. Differences therefore may be the result of environmental factors rather than different alleles.
How can comparing base sequences show genetic diversity
Technology has allowed us to determine the base sequences of DNA. We can measure genetic diversity of a species by sampling the DNA of its members and sequencing it to produce a pattern of coloured bands (each representing a different base). Analysis of this pattern allows us to compare same species or different species to see how diverse they are. These techniques also show the evolutionary relationship between species.
Why do we expect closely related species to have similar DNA?
When a species gives rise to another species by evolution, their DNA will initially be very similar. Due to mutations over time, the nucleotide bases in the DNA in new species will change. Over time, they will accumulate more differences in DNA.
How does amino acid sequence determine the genetic diversity of species?
The amino acid sequence is determined by mRNA, which in turn, is determined by DNA. Genetic diversity, within and between species can therefore be measured by comparing the amino acid sequence of proteins. The degree of similarity in the amino acid sequence will also determine how closely related species are.
What is sampling?
Sampling involves taking measurements of individuals, selected from the population of organisms which is being investigated.
Give 2 reasons why a sample might not be representative
- Sampling bias: Bias in the selection process. The investigators may make unrepresentative choices, deliberately or unwittingly.
- Chance: Individuals chosen by pure chance may still be unrepresentative.
Explain how sampling bias may be prevented
Remove human involvement by random sampling:
Method:
1. Divide the study area into a grid of numbered lines.
2. Using random numbers, from a table or computer generator, obtain a series of coordinates.
3. Take samples at the intersection of each pair of coordinates.
How can you minimise the effect of chance?
- Use a large sample size- less influence of anomalies
- Analysis of data collected - statistical tests determine the extent to which chance influenced variation.
What’s a normal distribution curve?
A bell-shaped curve that displays continuous variation
What’s a skewed distribution curve?
The normal distribution has shifted to one side. Shows the mean, median and mode have different values.
What’s standard deviation?
A measure of the width of the curve. It gives indication of the range of values either side of the mean.
