DIVERSITY Flashcards
State the 3 ways in which biological differences can be reflected
1) Large No. Of different species of organisms leading to genetic differences
2) Within a species, variation in individual characteristics
3) Cell differentiation in single multicellular organisms where different genes are expressed leading to different proteins produced
Explain why there is genetic diversity within a species
This is due to genetic factors. Also, environmental factors can influence variation in the characteristics shown by individuals within a single species
Name the 5 causes for genetic variation
1) Meiosis - Crossing over leading to different combinations of maternal + paternal alleles on a chromosome.
2) Meiosis - Independent segregation of homologous chromosomes. Leads to different combinations of maternal and paternal chromosomes in gametes
3) Random fertilisation of genetically different gametes. 2 gametes fuse at fertilisation at random and there is variation in the offspring
4) Gene Mutation - Change in DNA base sequence leading to different sequence of amino acids in polypeptide chain. different hydrogen, disulphide and ionic bonds will form and protein will have tertiary structure. This could lead to new feature in offspring
5) Chromosome Mutation - This non - disjunction can lead to different No. of chromosomes in the gametes produced in Meiosis
Environmental Factors also cause variation. In animals, this is diet and disease And in plants it could be light intensity and nutrient availability
State the definition of Genetic Diversity
The No. of Alleles in a population
Explain what Directional Selection is
This will occur in a changing environment. If a mutation leads to a some organisms having a favourable allele (favourable characteristic), these individual are more likely to survive. This feature will be more common and the unfavourable characteristic becomes rare; Antibiotic Resistance in Bacteria
Explain what stabilising selection is
This occurs in an unchanging environment. Selection is against individuals at both extremes of the characteristics (birth weight in humans)
State the definition of Species
A group of organisms with similar features that can interbreed to produce fertile offspring
State the definition of Taxonomy
The study of the principles of classification. Classification is a means of putting organisms into groups
What does hierarchical mean?
Small groups are placed into larger groups with no overlap between groups
What does phylogenetic mean?
The classification reflects the evolutionary relationships between the organisms
Name the 8 groups in the Classification system
Domain Kingdom Phylum Class Order Family Genus Species
How to calculate the name of an organism
2 part Latin name
The first word is the genus (Capital Letter). The second word is the species (lower case)
Give 4 reasons why Courtship Behaviour is important
- Allows recognition of same species
- Allows recognition of different gender
- Allows recognition of sexually mature individuals
- Stimulates sexual behaviour (mating), release of gametes
State 3 genetic comparisons to clarify relationships between organisms
- Comparison of DNA base sequence, more similar base sequence, the more closely related the species are
- Comparison of the mRNA base sequence (more similar = more closely related)
- DNA Hybridisation
State the way protein comparisons can be used to clarify relationships between organisms
Consider the aminos acid sequences of proteins. The more similar, the more closely related the species are. Always use same protein that is found in different organisms
State the way immunological comparison are used to clarify relationships between organisms
It compares variations in a specific protein that different species process. Used when amino acid sequence unknown
What is a community?
All the different species in the havitatq
How to measure biodiversity?
Simplest way = species richness = Count No. of different species present in a community
How do Farming Techniques affect Biodiversity?
Reduces species diversity. In agriculture, farmers may only grow one cell or keep one type of animal reducing species diversity. They may use herbicides (weedkiller) to kill weeds competing with crop. They may use pesticides (to kill pests/insects). If only one plant in area, reduces variety of food so fewer species will be found in the area.
How does Deforestation affect Biodiversity?
This is clearing of forests for conversion of the land for agriculture, housing, roads etc. No. of species will decrease; biodiversity decreases.
Give the ethical reasons for maintaining biodiversity
- Prevent Extinction of species
- Prevent Loss of Habitats
- Save organisms for future generations
Give the economic reasons for maintaining biodiversity
- Plants are a source of medicinal drugs
* Tourism
What is the formula for Index of Diversity?
d = N(N-1) / Sum of n(n-1)
N = Total No. of organisms of all species
n = Total No. of organisms of each species
Explain how DNA hybridisation works
DNA Hybridisation is when DNA molecules are compared. Hybrid DNA will have one strand from the 2 species being compared and hydrogen bonds will form between comp. Base pairs. The more closely related they are, the more hydrogen bonds will form and the more strongly they’ll be held together. To separate 2 strands of DNA a temp of 95 degrees is need but hybrid DNA will require a lower temp due to fewer hydrogen bonds, hence, the lower temp needed, the less closely related the species are
Define population
All of the organisms of one species in a habitat
Define community
All the different populations in a habitat
Define biodiversity
The variety of species in an area
Define species richness
number of different species in an area
What does the index of diversity describe?
The relationship between the number of species in a community and the number of individuals of each species
What is the index of diversity?
N(N-1) / The sum of (n(n-1))
In the index of diversity what is N?
Total number of organisms of all species
In the index of diversity what is n?
total number of organisms of each species
What are the effects of faming on biodiversity?
- Biodiversity is decreased- Forests are cleared- Hedgerows are removed- Monoculture
What happens as a result of monoculture?
- Fewer species of plant- Fewer species of insect- Fewer habitats and niches- Fewer food sources for other species
Why should farmers conserve biodiversity?
A more biodiverse area is more stable and less likely to be effected by changes
How can you compare genetic diversity?
- Within a species (intraspecific) or between species (interspecific)- Comparing characteristics- Comparing DNA sequence, mRNA sequence and amino acid sequence
What is the standard deviation?
The average variation of the data away from the mean
What size standard deviation is more reliable?
lower
What does it mean if error bars overlap?
No significant difference
What does it mean is error bars do not overlap?
Significant difference
What effect do pesticides have on biodiversity?
They decrease biodiversity
What is a species?
A group of similar organisms able to reproduce to give fertile offspring
What is species richness?
A measure of the abundance of each species in an area
What happens in response to directional selection in response to an environmental change?
Only individuals with favourable extreme characteristics can survive and reproduce and therefore pass on the allele for the favourable characteristic
What does a larger gene pool indicate?
Greater genetic diversity
What does natural selection result in?
Species being better adapted to their environment
How does natural selection take place?
Individuals with beneficial alleles and phenotypes are more likely to survive, reproduce and pass on the beneficial alleles to the next generation
What is the binomial naming system?
A universal way of classifying organisms, it uses Genus species
What is phylogenetics?
Comparing the relationships between organisms in a hierarchy
How are phylogenetics carried out by immunology?
Comparing different organisms ability to form anibody-antigen complexes. Organisms that can form the same antigen-antibody complexes are very closely related
Define taxonomy
The study of classification
Phylogenetics tells us what about an organism?
The evolutionary relationships of that organism
