Genetic Diversity And Clasification Flashcards
What is genetic variation?
The difference in DNA base sequence between individuals of the same population
What is genetic diversity?
The number of different alleles of genes within a population
What advantages does a high genet diversity of a population offer?
Ability to adapt to changes in the environment, allowing NATURAL SELECTION
Describe how natural selection results in the development of new characteristics?
Random mutations lead to the formation of new alleles of a gene (variation)
The allele codes for a specific characteristic that can lead to a survival advantage due to SELECTIVE PRESSURES (in the environment) like competition for food, mates
This enables organisms to survive and reproduce passing on the advantageous allele to the offspring
Overtime the frequency of the advantageous allele within the population increases (causes evolution of species to become better adapted to their environment)
What is directional selection?
When environmental conditions change, natural selection favours individuals with one EXTREME PHENOTYPE suited to the new condition who survive and pass on their genes
Overtime the mean of the population favours the EXTREME characteristic
Give and explain an example of directional selection
Antibiotic resistance
- bacteria with a mutation allowing them to survive in the presence of antibiotics will reproduce
- and he frequency of his allele will increase and the population will shift to have greater antibiotic resistance
What is stabilising selection?
When environmental conditions remain the same
Individuals closest to the mean are favoured (increase modal trait) and any new/extreme characteristics are selected against
Results in LOW DIVERSITY
Give an example of stabilising selection?
Birth weight of babies
What is disruptive selection?
Favouring individual with both extreme characteristics (starts speciation)
Give an example of disruptive selection?
Darwin’s finches and their different shaped/size beaks
- Extreme characteristics favoured causing formation of new species
What are the three types of adaptations and give examples?
Anatomical (body structure) - oily fur
Physiological (bodily processes) - venom production
Behavioural (actions) - hibernation
Define species?
A group of similar organisms that can interbreed to produce fertile offspring
What is taxonomy?
Taxonomy is the science of classifying and naming organisms based on their characteristics and evolutionary relationships.
What is phylogeny ?
The study of evolutionary relationships between organisms
How are organisms grouped in a phylogenetic classification system?
Organisms are grouped based on homologous characteristics that have the SAME EVOLUTIONARY ORIGINS in a hierarchy of graphs with no overlap
What is a hierarchy?
Groups within groups without a overlap
What is the classification hierarchy ?
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
What system is used to name species?
Binomial naming system
How does he binomial naming system work?
Genus species
- genus has a capital letter the species name doesn’t
- Underlined/italics
- Abbreviation after full (G. species)
What is artificial classification?
Divides species into groups based on analogous characteristics that have the same FUNCTION but a different EVOLUTIONARY ORIGIN
What is phylogenetic classification?
Divides species into groups based on homologous characteristics that have the similar EVOLUTIONARY ORIGINS but a different FUNCTION
How are phylogenetic relationships determined?
Structural similarities
DNA = more similar the more closely related the organisms
Fossil records
What is courtship behaviour?
A sequence of actions which is unique to species as it’s genetically coded for by genes
What is the importance of courtship behaviour?
Enables recognition of their own species and the opposite sex (to produce fertile offspring and prevent interbreeding)
Identify a sexually mature mate (capable of breeding) and form a pair bond (increases survival of offspring)
Synchronise mating behaviour
Give an example of some courtship behaviours?
Bower birds - construct structures decorate with sticks, leaves and stones
Puffer fish - plough brought sand creating ridges they decorate with shells
Bird of paradise- fan delicate wings and bob/strut
How can courtship behaviour aid classification?
The more closely related the species the more similar their courtship behaviour
Define classification?
The process or arranging organisms into groups
How can we clarify evolutionary relationships/identify genetic diversity between species?
Frequency of observable characteristics (gene difference reflected in phenotype)
The base sequence of DNA
The base sequence of mRNA = higher % base sequence similarity = more closely related
The amino acid sequence of protein
Immunology (albuiem) higher weight of precipitate the more closely related
What is a cladogram?
A cladogram is a diagram that shows the evolutionary relationships among different species based on shared characteristics
(Most recent common ancestor)
What is the concept of speciation.
Speciation is the process by which new species arise from existing ones due to genetic divergence and reproductive isolation.
