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