Bio 2 Unit 1 Vocab

Evolution

Mechansim of species for changing overtime

Natural selection

the process through which species adapt and change overtime in response to environmental pressures.

Lamar theory of evolution

Species evolved thriugh use and disuse of body parts

Darwin’s and Wallace observation

proposed evolution through natural selection

Descent with modification

1. Characteristics must be heritable

2. More offspring is produced that those who can survive so there is a competition for resources

3. Offsrping are not genetically idnetical to eachother

How can antural selection occur

1. if there is genetic diversity within individuals of a population

2. the variation is inheritable

Mutation

Change in DNA, original source of new alleles.

Effects of mutation in phenotype

• no effect’

• reduced fitnesss

• increased fitness

Sexual reproduction

• Leads to genetic variation by mixibng genes of parents

• Can lead to unique phenotypes

• These phenotypes may or may not have impact on fitness

Adaptation

Heritable trait that increases fitness in a individual

Consequences of evolution

• Gives rise to organism taht are related but look different

• Leads to speciation

• Gives rise to organisms that are not related but look simialr

Divergent Evolution

Organisms that have arecent common anvcestor evolve to produce different but realted species

Convergent evolution

organisms that do not have a recnt common ancestors evolve to have similar phenotypes

Ecological levels

Individual —> population (species) —> community —> ecosystem

Species

Group of organisms tahta re able to breed, and produce fertile and viable offspring.

Hybrids

Offspring produced by amting of individuals of different species

Gene flow

movement of alleles between and within a population

Speciation

formation fo two separate species from one original parent population

Allopatric speciation

physical separation from parent population

sympatric speciation

when both new popullations inhabit the new territory as parent species

Dispersal (allopatric) speciation

When a few emmbers of a population move to a certain area

Vicariance (allopatic) speciation

Whena geographical barrier physically separates the population

Adaptive radiation

relatively rapid evolution of many species form a single ancestor, ex. islands

gradual speciation

changes occur in small, intermediate steps and occurs gradually overtime

Punctuated equillibrium

new species diverge quickly from the parent species and then remain unchanged for longs periods of time

Sympatric speciation

populations inhabiting the sam egeographical range diverge into two separate species

Cause of sympatric speciation

Reproductive isolation

Types of reproductive isolation

• Temporal

• Behavioral

• Habitat

Benenfits of reproductive isolation

• Prevents individuals from differnt species from interbreeding

• Prevents gene flow from different species

Prezygotic barrier

Prevents mating from occuring or fertizilation

Postzygotic barrier

Zygotes do not develop and die or offspring is sterile

Temporal (prezygotic)

individuals reproduce at differnt times of the day/year

Habitat (prezygotic)

individuals klive in same geographic area but differnt habitats

Behavioral (prezygotic)

Mating cues/rituals are different

Mechanical (prezygotic)

Individuals have incompatible mating structures and/or gametes

Postzygotic barriers

Mating occurs, but

• Zygote does not develop

• Offspring is sterile

Reconnection of species

occurs because after separations, species may still interact with eachother termporarily or permanently

Hybrid zone

where two closely related species interact and reproduce

Reinforcement of speciation

When hybrid organism is less fit, it reinforces the division of species

Fusion

Reproductive barries weaken and species are joined together again

Stability

Barries remain teh same if hybrid is fit and reproducible

Microevolution

populations change overtime

Macroevolution

process that gave rise to new species and higher taxonomic groups

allele frequency

rate at which a specific allele appears within a population

fixed allele

every individual in the population carries said allele

genetic drift

whena llele in population chnages without known advantage to ther allele

founder effect

event that initiates allele frequency change in isolated part of a population

Hardy-Weinber equillibrium rules

• No mutations are occurring

• No migration or emigration (gene flow)

• No selective pressure for or against a phenotype

• An infinite population

Taxonomy

international classification system to name organisms in a hierarchical manner

Systematics

analyze organism based on evolutionary relationships

Phylogeny

evolutionary history of organisms and tehir relationship to other organisms

Phylogenic tree

uses systematics and phylogeny to reflect evolutionary relationships and history

Branch point

single lineage splitting into two

basal taxon

unbranched lineage that evolved from las common ancestor of all groups (outgroup)

polytomy

branch with three or more lineages

homologous structures

physical or genetic traits tahta re similar due to a common ancestor

analogous structures

similar physical or genetical traits that evolved separated in organisms withouth a recent common ancestor

shared ancestral character

character that originated in ancestor of taxon

shared derived character

not present in ancestor, novel evolutionary character

apomorphy

novel derived character

synapomorphy

shared derived (by las common ancertor and descendants)

autapomorphy

unique derived trait (novel character present in one group)

pleisomorphy

shared ancestral character, present in ancestor and descendants

monophyletic group

common ancestor and all descendants

clades

organisms taht descend froma common ancestor

paraphyletic group

ancestral species and some descendants

polyphyletic group

includes distantly related species but does not include most recent common ancestor