Natural selection Flashcards
(28 cards)
what is ecology ?
the study of living things within their environment
what is an ecosystem ?
a community of organisms and their surroundings
- basic unit of ecology
- numerous habitats - place where an organism lives
what is a niche ?
interacts within its environment
- it is a producer so produces food for other organisms
ecological niche - define
not only where a species lives but all of its activities its predators and how it interacts with the non living environment around it
what is adaptation ?
process by which an organisms becomes fitted to its environment
what are the three types of adaptations ?
- biological
- physiological
- anatomical
what is physiological adaptation ?
changes to the metabolism of the organism which are advantageous to survival in their particular habitat
what is anatomical adaptation ?
involves how body structures adapt to regulate heat loss
what is behavioural adaptation ?
these the actions by the organisms which help them to survive and reproduce
exotherms - define
cannot regulate their body temperature internally
what is evolution ?
the development of new types of living organism from pre existing types by the accumulation of genetic differences over a long period of time
when did Charles Darwin put forwards his ideas ?
1859
how do you prevent fossils from being formed or found
?
- scavengers, bacterial action - decompose and dismember dead plants and animals
- stopping fossils being formed: never found, recovered or interpreted
dating fossils, carbon dating
present in CO2
- C14 taken in by plants
- eaten by animals
- has a half life about 5700 years
what is proteomics ?
the study of proteins coded for specific genes
gene pool - define
the total variety of genes and alleles present in a sexually reproducing population
speciation - define
is the process by which one species evolves into a new species
how is speciation more likely to occur ?
- part of the population is isolated in some way - gene pool isolated population changes
what is allopatric speciation ?
two populations are totally separated from each other by a physical barrier - prevents interbreeding
what does geographical isolation lead to ?
allopatric isolation
what is geographic isolation ?
before isolation - share a common gene pool
after isolation - natural selection, mutations and random genetic drift occur in both populations
what is sympatric speciation ?
two populations can mix freely in the same area but some individuals accumulate changes in their gene pools - no physical barrier
what occurs in reproductive isolation?
occurs when changes are brought about by natural selection
what is stabilising selection ?
occurs when conditions are favourable and not changing
- maintains the favourable characteristics make species successful - eliminates alleles that are harmful or useless
