Evolution, speciation and natual selection Flashcards
What were Darwin’s observations?
Offspring are genetically similar to their parents, no 2 individuals are identical (variation), organism produce a large number of offspring and population numbers remain fairly stable
What were Darwin’s conclusions?
There is a struggle for survival, better adapted individuals survive and pass on their characteristics and over time, a number of changes may result in a new species
What is natural selection?
The selection y the environment of particular individuals that show certain variation, and these individuals will survive to reproduce and pass on their characteristics variations to the next generation through their genes
What is speciation?
The formation of a new species
What is selection pressure?
A factor in the environment that may act as a selective force driving evolution in a particular direction
What are examples of selection pressure?
Availability of food, predators, diseases and physical & chemical factors
What is the genetic reason for why there is variation within a population?
Differences in DNA between individuals and mutations as individuals posses different forms on the same gene
What are 2 reasons for variation within a population?
Genetic and environment
What is the environmental reason for why there is variation within a population?
The environment gives rise to variation by acting with genes
Why does the population stay stale?
More offspring are produced than actually survive, as many organisms die
What is their competition for between individuals?
Food, light, water, a mate and a nest
How does natural selection work?
Better individuals are more likely to survive and successfully reproduce, so the frequency of the allele giving rise to the advantageous characteristic will go up from one generation to the next and offspring will tend to inherit allen’s responsible for features that helped their parents survive
How does speciation work?
Many changes in many genes due to natural selection gives rise to a new species
What is the effect of small changes?
Individuals may no longer e ale to interbreed freely to produce viable offspring cause of accumulation
What is the impact of individuals no longer being ale to interbreed freely?
Subpopulation becomes so different from eachother, so they become a different species
What is are examples of natural selection?
Antibiotic resistant bacteria, peppered moths, sheep blowflies and flavobacterium
How has resistance evolved in insects?
Insect crop pests are sprayed with insecticides and some survive due to an adaptation, so these insects breed and resistance increases
What is antimicrobial resistance (AMR)?
When a microbe acquires a genetic mutation, making it resistant to the effect of one or more antimicrobial agents that were once effective
How can AMR be acquired?
Spontaneously or by gene transfer
Why is there increasing rates of AMR?
Antibiotic use both within human and veterinary medicine
What is the effect of use of antibiotics?
Selective pressure increases in a bacteria population, promoting resistant bacteria to thrive and susceptible bacteria to die off
What are common antibiotics?
Penicillin, streptomycin, ampicillin and tetracycline
What is a common drug resistant bacteria?
MRSA
How does most evolution occur?
As a negative result of selection pressure
How is flavobacterium an example of natural selection?
It is found in wastewater of factories that make nylon 6, which has evolved to digest nylon and is beneficial to humans to clear factory waste
