NATURAL SELECTION + EVOLUTION Flashcards
What is sexual dimorphism? (1)
when the males and females of a certain species look different.
what is meant by temporal isolation? (1)
changes in reproductive cycles.
what is meant by behavioural isolation? (1)
are subject to a sexual selection, a gender has a specific mating ritual.
what is meant by gametic isolation? (1)
female gametes fail to attract a male gamete or male gamete cannot penetrate the female gamete.
what is meant by mechanical isolation? (1)
there is a physical barrier to fertilisation that results from a mutation.
what is meant by ecological (habitat) isolation? (1)
live in a single habitat but develop characteristics that enable them to survive in different niches.
what are some causes of allopatric speciation? (2)
-geographical isolation - are separated by a physical barrier such as a river, stream or shifting land.
what is sympatric speciation? (1)
a species isolated from each other without a physical barrier.
when does speciation occur? (1)
when gene flow has effectively stopped between populations where it previously existed. this requires to populations to become reproductively isolated.
what are some causes of sympatric isolation? (5)
-ecological (habitat) isolation
-mechanical isolation
-gametic isolation
-behavioural isolation
-temporal isolation
what is allopatric isolation? (1)
a species geographically isolated from each other by a physical barrier.
what are the types of speciation? (2)
-allopatric speciation
-sympatric speciation
what did Darwin use to prove his theory on natural selection? (4)
-living species
-comparative anatomy
-fossils
-artificial selection
what evidence did Darwin accumulate to prove his third observation? (1)
the favourable characteristics are expressed in the phenotypes of their offspring (better survive and reproduce)
what evidence did Darwin accumulate to prove his first observation? (2)
the over population of offspring in the wild leads to competition for resources. in a stable populations, breeding pairs give rise to a single breeding pair of offspring
what is a ectotherms? (1)
animals that are unable to regulate their body temperature effectively by internal means and rely on absorbing heat from their surroundings.
what is speciation? (1)
the formation of a new species.
what is ecology? (1)
the study of living things within their environment.
what evidence did Darwin accumulate to prove his second observation? (1)
shows variation in their characteristics, when genetic variation occurs in their development.
what is a endotherms? (1)
an animal who’s body heat comes from the metabolic reactions of many body organs (depends on the volume of the body)
what is a ecosystem? (1)
a community of organisms and their surroundings - the environment in which they live.
what is meant by intraspecific variation? (1)
means variation within a species (such as eye colour)
what is meant by interspecific variation? (1)
variation between species.
what is chemosynthesis? (1)
a method used by some micro-organisms to release energy from inorganic molecules (ammonia or metal sulphides)
what are some environmental pressures? (4)
-availability of suitable food
-diseases
-predators
-physical, biological and physiological determinants
what is the molecular evidence for evolution? (6)
-all have DNA or RNA a genetic material
-genetic code is universal
-ATP is the universal molecule for energy storage
-same 20 amino acids are used
-all have phospholipid membranes
-physiological processes follow the same metabolic pathway
describe what is meant by natural selection? (1)
used to describe the process of environmental factors determining which individuals will survive.
what is meant by selection pressure? (1)
individuals who survive have been selected from the entire population.
what is a ecological niche? (1)
the functional position of an organism in its environment.
what does a niche comprise of? (3)
-the habitat
-activity pattern
-resources obtained from habitat
what was Darwin’s third observation for natural selection? (1)
organisms have the ability to produce large numbers of offspring.
what was Darwin’s fourth observation for natural selection? (1)
populations in nature tend to remain fairly stable in size - there must be a ‘fight’ for survival, survival of the fittest.
what was Darwin’s second observation for natural selection? (1)
no two individuals are identical - therefore variation is occurring
what are physiological adaptions? (1)
any adaption which ensure the correct functioning of cellular actions and processes
what is an example of a physiological adaption? (1)
production of venom in spiders and snakes
what was Darwin’s first observation for natural selection? (1)
1) offspring generally appear similar to their parents - therefore traits must be passed down.
what is an example of an anatomical adaption? (1)
the kangaroo rat - elongated loop of Henle in kidney for reabsorption of water adapted for desert environment.
what is an example of a behavioural adaption? (1)
agoutis bury Brazil nuts as a food store
what is an adaption? (1)
used to describe variations which help an individual to survive.
what is a behavioural adaption? (1)
actions by the organism which help them to survive or reproduce.
what is meant by variation in terms of evolution? (1)
there must be differences between the individuals in a population.
what is meant by the reproductive advantage? (1)
the ability for an individual to pass on advantageous genes (alleles) because of their survival.
what are anatomical adaption? (1)
adaptions which are changes to structures which can be seen or observed when an organism is dissected.
what is meant by evolution? (1)
the process by which different kinds of living organisms are believed to have developed from earlier forms during history.
what is meant by hereditary in terms of evolution? (1)
the differences between organisms must be heritable.
what is meant by means of selection, in terms of evolution? (1)
there must be a mechanism or pressure that selects some variables for the next generation at the expense of others.
what conditions are needed for evolution to occur? (3)
-variation
-hereditary
-means of selection
what are the type of adaption? (3)
-anatomical
-behavioural
-physiological (biochemical)
what is biodiversity? (1)
Biodiversity can be thought of as all the variation that exists within and between all forms of life.
what is directional selection? (1)
this occurs when environments are changing and there is a clear advantage in the population changing in one particular direction.
what is stabilising selection? (1)
this occurs where conditions are favourable and not changing so pressures to change in one way are less than advantage in remaining the same.
what is the aim of interbreeding programmes? (3)
endangered species are carefully bred to increase genetic diversity and population size, its maintained via the exchange of organisms and gametes, keeping stud books, preventing interbreeding and techniques such as IVF
how do scientists detect relatedness using immunological studies? (4)
-protein molecules present in serum acts as antigens when serum is inserted into animals with an immune system that lacks these particular proteins.
-the inserted serum triggers the production of antibodies against the injected ‘foreign proteins’
-fresh serum produced from the blood is tested against the serum of other animals
-the more closely related the animal is to humans the greater the precipitation observed
what does DNA hybridisation involve and what does it tell us? (2)
involves matching DNA from different species to test the degree of base pairing that occurs, this tells us the approximate degree of divergence between closely related groups.
what is the similarities between species richness and species diversity? (2)
-both species richness and species diversity measure the number of different species (in a community)
-species diversity takes into account the abundance of species/relative abundance distribution, whereas species richness does not
why would a captive breeding programme begin to release individuals into the wild? (1)
the number of births of the species is rising which causes an increase in population so, more are born than released.
what is the reproductive model, in terms of species? (1)
a group of organisms which can interbreed to produce fertile offspring
what is meant by an endemic species? (1)
a species only found in one geographical location
how are seeds selected for storage in seed banks? (3)
-from different plants - to provide genetic variation
-x rayed to check for viability/viable embryos
what is molecular phylogeny? (1)
the analysis of molecular differences in different organisms to determine the extent of their evolutionary relationship
what are the disadvantages of the reproductive model of species? (1)
as cross-breeding occurs and some members of the same species don’t interbreed due to geographical isolation but would produce fertile offspring.
what is genetic diversity? (1)
a measure of the genetic variation found in a particular species, the number of alleles in a gene pool.
what are the different forms of ex-situ conservation? (3)
-captive breeding programmes
-reintroduction programmes
-seed banks
what is evolution? (1)
The development of new types of living organism from pre-existing types by the accumulation of genetic differences over long periods of time.
what is proteomics? 91)
the study of the proteins coded by specific genes found in the human genome
what are some examples of in-situ conservation? (2)
-education programmes
-initiate such as national parks and sites of specific scientific interest
what is geographic isolation? (1)
occurs when natural or human-imposed barriers arise and sharply restrict movement of individuals between the divided populations.
what new evidence supports evolution? (3)
-fossils (palaeontological evidence)
-immunological studies
-genetic differences in nucleic acids
what are the types of allopatric speciation? (1)
geographical isolation
what are the different types of fossils? (4)
-petrified remains
-moulds
-traces
-preserved, intact whole organisms
what is sympatric speciation? (1)
this occurs when two populations are still able to mix freely in the same area but some individuals accumulate changes in their gene pool, which are sufficient to prevent interbreeding.
what are the types of sympatric speciation? (6)
-mismatch of genitalia
-barriers of fertilisation
-formation of sterile hybrids
-behavioural changes
-temporal changes
-ecological change.
how can immunological studies help illustrate relatedness? (1)
the immune reactions provides a mechanism of detecting differences in specific proteins and therefore their relatedness
what is an ecosystem? (1)
a community of organisms and their surroundings - the environment in which they live
what are the types of selection? (2)
directional and stabilising selection
when does directional selection occur? 91)
associated with changing environment conditions.
when does stabilising selection occur? (1)
occurs where environmental conditions are stable and largely unchanging
what is an ecological niche? (1)
describes not only where a species lives but all of its activities such as feeding, its predators and how it interacts with the non-living environment around it.
what is meant by the evolutionary race? (1)
as these species evolve, other species must evolve with it, (close symbiotic relationships)
what does IUCN stand for? (1)
international union for the conservation of nature.
what are the steps of seed bank preparation? (5)
-seed drying (below 7% water)
-packaging (in moisture proof container)
-storage (temperature of -188)
-periodic germination tests
-restorage or replacement
what are seed banks? (1)
the natural dormancy of seeds allows for their suspended preservation for long periods
what does N stand for in the biodiversity index? (1)
total number of organisms of all species found
what does n stand for in the biodiversity index? (1)
number of individuals of each species
what is serum? (1)
serum is the liquid produced from blood when blood cells and fibrinogen have been removed
what conditions are needed for seed banks? (2)
low temperature and low humidity
