Biology test terms

gene

gene

a section of dna that codes for a particular trait and contributes to the genotype

hi

hi

genetic drift

random change- wrong place wrong time

Zygote

fertilised egg once the gametes have fused together

Stabilising selection

moderate trait is favored 

Directional selection

one extreme trait is favored 

Disruptive selection

select against two extremes are favored 

fundamental niche

ideal world, limiting factor is abiotic

realised niche

real life, limiting factor is biotic

niche

adaptations that allow you to have your way of life

modes of natural selection

directional, stableising, disruptive

speciation

population evolves to become a separate species

isolating mechanisms

prezygotic, postzyotic

gradualism

slow changes of form over time

founder effect

small group breaks off and forms a new population

bottle neck effect

large population suddenly reduced in size

gene pool

alleles present in a population

divergent evolution

common ancestor splits into two new species

evidence for divergent evolution

homologous structures

selecting agents

competitors, predators

species

group of organisms that can breed to produce fertile offspring

punctuated equilibrium

long periods of stasis followed by rapid bursts of evolution

node

point on a phylogenic tree that branches

Adaptive radiation

common ancestor splits into many new species due to niche availability

convergent evolution

no common ancestor, similar selection pressures select for similar phenotypes. never can be the same species

convergent evolution evidence

analogous structures

co-evolution

have a close relationship, no common ancestor, act as selection pressures on one another

polyploidy

change in chromosome number

euploid

whole set of extra chromosomes

aneuploidy

plus or minus one chromosome

autopolyploidy

chromosomes from the same species

allopolyploidy

chromosomes come from different species, infertile

autoplolyploidy fertility

fertile, somatic doubling, amphiploidy, instant speciation

allopatric speciation

the result of the formation of a geographical barrier

sympatric speciation

speciation without geographical barrier, due to disruptive selection with competition becoming a selecting agent

deme

a group of organism that are partially isolated from the population

cline

evolution of a characteristic in a straight line

genome

genetic information of a organism

vicarnence

geographical separation of a population

fossils

preserved remains left by organisms that died

comparative anatomy

comparison of body structures between different species- similarities indicates evolution from a common ancestor

biogeography

evolution evidence form the geographical distribution of species

transition forms

change in fossils forms over time

sexual selection

he process by which a female chooses a better-suited male to reproduce

evidence for evolution

fossil, comparative anatomy, molecular biology, biogeography

processes that lead to evolution

mutation, natural selection, geneflow

homologous structures

similar structure different function

analogous structure

similar function different structure

pre zygotic isolating mechanisms

geographical, ecological, temporal, behavioural, structural, gamete incomparability

post zygotic isolating mechanisms

hybrid inviability, hybrid sterility, hybrid breakdown

patterns of evolution

gradualism, punctuated equilibrium

RIM

factor that prevents inbreeding between two species

pre zygotic

before fertilisation

post zygotic

after fertilisation