Biodiversity Flashcards
What is speciation
Formation of a new species due to either geographical structural or behavioural isolation
Why is it an issue to collect data from twin studies
Scientist chooses twins which introduce bias
Not a large enough sample size to get reliable results
What is courtship behaviour and describe the steps of the SRC
The way organisms act to attract each other and allow mating
Male signals female to mate either with a visual or sound stimulus (1st behavioural element)
Female responds with a specific stimulus of her own (2nd behavioural element)
Female either male to continue or terminate courtship behaviour
What evidence can be used to construct phylogenetic trees
Molecular taxonomies
DNA base sequence
DNA hybridisation
Immunological protein comparison
Amino acid sequences in specific proteins like Hb
Phylogenetic taxonomies
Embryology
Fossil evidence
Similar biological structures
Define hierarchy
Groupings that decrease in size and are fully contained in taxa with no overlap
What is courtship behaviour and what does it allow?
Courtship behaviour - The way organisms behave in order to attract each other and allow mating
Allows:
Species recognition
Identify a mate that is sexually mature and is able to produce fertile offspring
Synchronised mating when both partners are sexually mature and ready to mate
Form a pair bond and stay together for life
What causes genetic variation
Random mutations which get passed down to offspring
Meiosis shuffles all chromosomes so all gametes are different
Fertilisation - Each gamete is different so each fertilisation is different
What factors decrease genetic diversity
Genetic bottleneck - A catastrophic event that decreases more than 50% of a population which severely decreases the variety of alleles leaving only a few to be passed on for generations
Founder effects - G.D is reduced as a small number of founders represent a small number of original alleles, founders less likely to adapt to the surrounding environment same alleles passed down to offspring which overall decreases G.D
Selective breeding - Only desired alleles are chosen and others are lost and unused which overall decreases G.D
Describe the dizygotic twin studies (Non-Identical)
Have different genotypes as they came from 2 sperm and 2 egg cells
Brought up together in same place
Give IQ tests and collect results
If scores show 85% concordance then most likely environmentally controlled
If scores show 20% concordance then most likely genetically controlled
Describe the monozygotic twin studies (Identical)
Have same genotype as they came from 1 sperm and 1 egg cell
Separated from birth
Give IQ tests and collect results
If scores show 85% concordance then most likely genetically controlled
If scores show 20% concordance then most likely environmentally controlled
What is discontinuous variation
Categoric phenotypes caused by 1 or 2 alleles (non-polygenic) and not usually affected by environment
What is continuous variation
(Non - Categoric) Range of phenotypes caused by lots of genes interacting, multiple alleles and from the environment
Define species
Group of organisms with observable similar characteristics which can also interbreed and produce fertile offspring
What is genetic diversity
Variety of different alleles in a population
What are the 3 types of selection
Directional selection where the population after selection moves left or right to the original population Beneficial for one extreme trait but bad for opposite extreme trait
Stabilising selection where the population after selection gets narrower and taller to the original population Beneficial for moderate traits bad for extreme traits
Disruptive population where the population after selection goes against the mean Beneficial for extreme traits bad for moderate traits
What 3 types of taxonomy are there and what are they based on?
Hierarchal taxonomy - Organisms are classified based on shared observable features
Phylogenetic taxonomy - Organisms are classified based on their evolutionary ancestry
Molecular taxonomy - Organisms are classified based on biological molecules which can how similarities or differences between organisms
What are the 2 types of speciation
Allopatric speciation - part of population gets isolated due to geographical reasons and develops new alleles which pass on for generations and eventually create a new species
Sympatric speciation - Genetic polymorphism within population, genes are passed on until eventually new species is formed within same population
What is the NBC and what is it based on
Natural Biological Classification
Morphology - The more similar biological features 2 organisms share the more closer they are thought to be
Fossil records - Provide clues for evolutionary relationships
What are some problems with classifying species
Artificial selection - no more observable similar characteristics
Evolution -
Hybrids - Different species breed and produce infertile offspring
Isolation - Isolated species could be mistakenly classed as part of another species
