1. Evolution and the Niche Flashcards
The genotype of an individual
The genotype of an organism is its complete set of genetic material. Genotype can also be used to refer to the alleles or variants an individual carries in a particular gene or genetic location
the phenotype of an individual
Phenotype refers to an individual’s observable traits, such as height, eye color and blood type. A person’s phenotype is determined by both their genomic makeup (genotype) and environmental factors
A person’s phenotype is determined by
both their genomic makeup (genotype) and environmental factors
fitness
the ability of organisms- or populations or species- to survive and reproduce in the environment in which they find themselves, and thus contribute genes to the next generation.
the ability of organisms- or populations or species- to survive and reproduce in the environment in which they find themselves, and thus contribute genes to the next generation is refereed to as
the fitness of an organism
what is a mechanism of evolution where organisms that are more adapted to their environment are more likely to survive and pass on the genes that aided their success. This process causes species to change and diverge over time
natural selection
Natural Selection
Natural selection is a mechanism of evolution. Organisms that are more adapted to their environment are more likely to survive and pass on the genes that aided their success. This process causes species to change and diverge over time
situation:
there are green and brown beetles
birds prefer brown beetles and only eat the green
what happens generations later and what is this an example of
generations later the green beetles have been selected against and brown beetles have been flourished
this is an example of natural selection
adaptation
- Adaptation is the evolutionary process whereby an organism becomes better able to live in its habitat or habitats.
- Adaptedness is the state of being adapted: the degree to which an organism is able to live and reproduce in a given set of habitats
the evolutionary process whereby an organism becomes better able to live in its habitat or habitats is called
adaptation
the degree to which an organism is able to live and reproduce in a given set of habitats is referred to as
the state of being adapted
artificial selection
An evolutionary process in which humans consciously select for or against particular features in organisms –
for example, by choosing which individuals to save seeds from or breed from one generation to the next.
People have been artificially selecting plants and animals for thousands of years
example of artificial selection by humans
choosing which individuals to save seeds from or breed from one generation to the next.
People have been artificially selecting plants and animals for thousands of years
An evolutionary process in which humans consciously select for or against particular features in organisms is called
artificial selection
what is the basis of the biological species concept
empirical test proposed to determine whether or not two populations were part of the same or different species.
Recognized that organisms belonged to a single species if they could (at least potentially) breed together in nature to produce fertile offspring
The biological species concept defines
a species as members of populations that actually or potentially interbreed in nature, not according to similarity of appearance. Although appearance is helpful in identifying species, it does not define species.
organisms belonged to a single species if they could
(at least potentially) breed together in nature to produce fertile offspring
a species
a group of interbreeding natural populations that are reproductively isolated from other such groups
can populations which are indistinguishable from morphologically be classified as separate species if they do not interchange genes?
Yes, populations that are morphologically indistinguishable can be classified as separate species if they do not interchange genes
how are biological species maintained?
keep them reproductively isolated
reproductive isolating mechanisms is
anything that prevents the flow of genes from species, such as species living in close proximity to each other, so that they remain distinct from one another
the 2 broad types of reproductive isolating mechanisms
1) premating or prezygotic mechanisms
2) postmating or zygotic isolating mechanisms
premating or prezygotic mechanisms reproductive isolating mechanisms
1) ecological or habitat isolation (populations occur in different habitats)
2) seasonal or temporal isolation (eg- mating or flowering times occurring in different seasons)
3) sexual isolation (mutual attraction between different species is weak or absent - see this over time in songbirds that have been geographically isolated for a long time)
4) mechanical isolation (physical, non correspondence in genitalia or flower parts)
5) isolation by different pollinators (related species attract different pollinators)
6) gametic isolation (gametes nonviable)
postmating or zygotic isolating mechanisms reproductive isolating mechanisms (mating taking place)
1) hybrid in viability (hybrid zygotes have reduced viability or are in viable- the offspring dont survive at all)
2) hybrid sterility (offspring will survive but they in turn cannot reproduce eg- with mules )
3) hybrid breakdown (hybrids have reduced viability or sterility )
what is a condition in the context of species distribution and abundance
need to know the organisms’ history, resources, what is it required to survive, individual rates of births, deaths and migration, interactions with their own as well as other species and the effects of its environmental conditions
the condition is defined as a abiotic environmental factor that influences the functioning of organisms
eg- temperature, ph, salinity (these condtions in turn can be altered by the presence of another organism)
example of a condition that can be changed/altered by the presence of other species
trees creating shade for other organisms (that reduces the amount of light that is reaching the forest floor- organisms changing the conditions for other organisms)
how do conditions differ from resources
conditions are not depleatable
conditions and resources can differ depending on
the organism
eg- solar radiation might be considered a condition for a insect but a resource for a plant
some abiotic parameters can also be considered both resources and conditions depending on the situation
example -
so a plant uses water as a resource but if you have too much water from heavy rainfall that can wash away the plant = unfavourable condition
environmental variability
several environmental parameters (conditions) may vary
temperature
acidity
salinity
osmolarity
radiation
these in turn have direct physiological and behavioral impacts on organisms
environmental variability have direct physiological and behavioral impacts on
organisms
if competition and predation affect the niche of an organism by reducing it, what effect would muralists have on a realized niche of an organism?
mutalists benefit one another
if a organism comes along that mutually benefits me i would expand my realized niche
realized niche would be expanded
types of speciation
Allopatric Speciation
Parapatric speciation
sympatric speciation
speciation
Speciation is how a new kind of plant or animal species is created.
Speciation occurs when a group within a species separates from other members of its species and develops its own unique characteristics
Allopatric Speciation
new species evolves in geographic isolation from parent species
when a geographic barrier divides a population into two smaller populations
easiest one
Parapatric speciation
occurs where the speciating populations are contiguous and hence only partially geographically isolated
when a small group breaker off from a larger group and forms a new species due to physical barriers - difference is one group that left is much smaller than the other and this small group may have different traits reflected in new generations
eg- larus gulls
Niche
niche is not a place but an idea
niche is the summary of the organisms tolerance and requirements
not only talking about 1 environmental condition (such as temperature) but a combination of several different conditions)
organisms can change their niche as they develop
habitats typically consist of many different niches supporting many different species
sympatric speciation
speciation where there is no geographic separation between the isolating populations
occurs through a change in host preference, food preference, or habitat preference in order to prevent new species from being swamped by gene flow
