3.2 Natural Selection Flashcards
define natural selection
the process by which the organisms that are best adapted in a particular environment are most likely to survive and reproduce passing on their advantageous alleles to their offspring.
define genotype
the genetic makeup of an organism with respect to a particular feature
define phenotype
the physical traits (including biochemical characteristics) expressed as a result of the interaction between the genotype and environment
a niche is. . .
a niche is the role of an organism within the habitat in which it lives.
identify and describe 3 types of adaptations
ANATOMICAL- an adaptation involving the form and structure of an organism
PHYSIOLOGICAL- an adaptation involving the way the body of the organism works, including differences in biochemical pathways or enzymes
BEHAVIOURAL- an adaptation involving programmed or instinctive behaviour making organisms better adapted for survival.
define selection pressure
the pressure exerted by a changed environment or niche on individuals in a population, causing changes in the population as a result of natural selection
_____ _______ is the evolution of dark coloured individuals in a habitat that has been made darker by industrial pollution
INDUSTRIAL MELANISM is the evolution of dark coloured individuals in a habitat that has been made darker by industrial pollution
what is directional selection?
directional selection is natural selection showing a change from one dominant phenotype to another in response to a change in the environment - one phenotype is selected for over all the others.
a _____ _______ is all the variants of all the genes in a population.
a GENE POOL is all the variants of all the genes in a population.
Outline the theory of evolution
living organisms that reproduce sexually show great variety in their appearance
organisms produce an excess of offspring - many organisms produced do not survive to reproduce themselves . therefore there is constant competitions between members of the same species
organisms that inherit characteristics that give them an advantage to survive and pass on the desired feature to their offspring.
organisms inherit characteristics that put them at a disadvantage will be more likely to die out before they can reproduce.
difference between natural selection and evolution
natural selection is the process by which evolution occurs but natural selection does not necessarily lead to the evolution of a new species
Identify the types of adaptations that organisms require to successfully adapt for their niche
Anatomical Adaptations- form and structure of organism.
Behavioural adaptations- changes in programmed or instinctive behaviour making organisms better adapted for survival.
Physiological adaptations- the way the body of the organism works, includes differences in biochemical pathways or enzymes
Outline the evolution of antibiotic resistance by natural selection.
Original population includes some mutations
Antibiotic is taken
Bacteria with resistant mutation more likely to survive
New population has higher proportion containing the advantageous resistant bacteria.
Antibiotic taken
Only bacteria with resistant mutation survive
New population almost entirely resistant to antibiotic apart from new mutants.
Reasons behind the antibiotic resistance bacteria problem
Antibiotics too widely prescribed/used
Not completing courses of antibiotics
Antibiotics used in food chains
Lack of hygiene in hospital spreads MRSA
Ways of overcoming antibiotic resistance problem
Reduce the use of antibiotics
Better education to make people understand they do not need antibiotics
Reduce use of antibiotics in farm animals
Development of new antibiotics
Define speciation
the formation of new species
Define hybridisation
the production of offspring as a result of sexual reproduction between individuals from 2 different species
Define Allopatric speciation and the other one
Allopatric- speciation that takes place when populations are physically or geographically separated so that there can be no interbreeding and or geneflow between populations
Sympatric- speciation that takes place between populations of species living in the same place. they become reproductively isolated by mechanical, behavioural or seasonal mechanisms and gene flow continues between the populations to some extent as speciation takes place
An ________ species is a species that evolves in geographical isolation and is found in only one place.
An ENDEMIC species is a species that evolves in geographical isolation and is found in only one place.
_________ ___________ occurs when two populations inhibit the same region but develop preferences for different parts of the habitat.
ECOLOGICAL ISOLATION occurs when two populations inhibit the same region but develop preferences for different parts of the habitat.
define Adaptive radiation
Adaptive radiation is the process by which one species evolves rapidly to form a number of different species that all fill different ecological niches
identify and describe the 3 types of Sympatric isolations
Types of SYMPATRIC Isolations:
BEHAVIOURAL- when changes occur in courtship ritual, display or mating patterns so some animals do not recognise others as being mating mates.
MECHANICAL- when a mutation occurs that changes the genitalia of animals making it physically impossible for them to reproduce weight other members of the group.
SEASONAL- when time of flowering/sexual receptiveness in some parts of the population drifts way from the norm of the group. this can lead to groups reproducing at different times
