hsc biology - mod 3 biological diversity

module3 blue = actual definition purple = what it does; special features

adaptation

anything that an animal or species has that suits it to its environment and makes it more likely to survive and reproduce successfully under a selective pressure

structural adaptation

a body part is altered to suit the species to an aspect of its environment and allow it survival against a selective pressure

physiological adaptation

a function of an animals body system or organ that allows it survival or reproduction against a selective pressure

behavioural adaptation

a way of acting that better suits an animal to its environment or allows it survival against a selective pressure

genetic variation

differences in DNA that can be passed on from parents to offspring. leads to phenotypic variation

reproduction for replacement

when a species will produce far more offspring than would be required to replace the parents as a result of struggle for survival

struggle for survival

predation and environmental pressures lead to only a few offspring hatching and surviving to adulthood

natural selection

the key mechanism to evolution. it is differential survival and reproduction of individuals in a species, due to selective advantages and disadvantages conferred by heritable differences in their phenotype.

sexual selection

reproduction is more important than survival. some species are favoured for their reproduction at the expense of survival

directional selection

a mode of natural selection in which an extreme phenotype is favoured over other phenotypes causing the allele frequency to shift over time in the direction of that phenotype

allopatric speciation

one species diverging when a parent population is

• divided by a geographical barrier,

• there is no gene flow between each population,

• mutations arise in each population and

• different selection pressure operate in each population.

the two daughter populations evolve to become so different that they can no longer mate and produce fertile offspring.

greek for ‘other country’

divergent evolution

an ancestral species branches off into two or more species

convergent evolution

two unrelated species are placed under similar selection pressures to evolve similar adaptations independently.

punctuated equilibrium

evolution occurs in short rapid bursts followed by a species becoming stable for a long period of time (~100 years)

explanation for why there arent more transitional fossils

selection pressures

the way that some environmental factors differentially affect the survival and reproduction success of certain phenotypes in a population

abiotic selection pressures

_____ created by a non-living thing

• weather conditions

• temperature

• aridity

• incorrect exposure to light

biotic selection pressures

____ created by a living thing

• competition for shelter

• competition for mates

• scarcity of food

• predation

• disease

selecting agent

the specific environmental factor that creates a selection pressure for a specific phenotype

selective advantage

a feature that helps an animal survive or reproduce under a selection pressure compared to other members

vestigial structure

an anatomical feature that no longer has a purpose in the current form of a species but did in its ancestor

homologous structure

structural feature in multiple animals meant to have the same fundamental value but end up with different purpose

e.g. limbs of humans vs birds vs whales

analogous structure

structural feature in multiple animals with different structure but same fundamental value

e.g bat wing being like fingers and membrane vs birds being bone with feathers and insect having no bone

comparative embryology

looking at how embryos of different animals look similar could prove a common ancestor

biogeography

the study of the distribution of species in geographic space and through geological time