Evolution

Jean Baptiste theory

Traits can be aquired or lost during an individuals lives and past off to offspring

Charles Darwin theory

Natural selection can explain evolution and species diversify over time through the survival of the fittest.

Book by Charles Darwin

1858, On the Origin of Species

Lamarck's source of change

need

Lamarck's mechanism

use vs disuse

Lamarck's time of change

Lifetime of individual

Lamarck's inheritance

transmission of acquired traits

Lamarck's scientific validity

None

Lamarck's extinction

Species do not got extinct without human intervention

Darwin's source of change

Variation already exists

Darwin's mechanism

Natural selection

Darwin's time of change

Over generations

Darwin's inheritance

Genetic traits inherited

Darwin's scientific validity

Supported with scientific evidence

Darwin's extinction

extinction occurs

Evolution

The change in allele frequency over many generations

Evolution is not goal directed

evolution is random and occurs based off natural selection and survival of the fittest.

Organism variation

differences in characteristics between individuals in the same species

Mutations

Random, permanent changes in DNA sequence. Mutations in gametes are passed to offspring.

Genetic Recombination

Sexual reproduction shuffles genes creating new allele combinations

Crossing over

Prophase 1, DNA segments between homologous chromosomes during meiosis

Independent assortment

Metaphase 1, Randomizes which parental chromosomes end up in a gamete

Random fertilization

Combines unique gametes from two random parents

Gene flow

Individuals move into new populations, introducing new combinations

Genetic drift

Random selection that is not based off of fitness but rather external factors

Natural selection

Individuals with more favourable traits are more likely to survive and reproduce

Selection pressures

Enviromental factors that affects survival

Adaption

Species eventually choose favourable traits to adapt to enviroment

Speciation

When a group of population drifts away creating new genomes and a new species

Extinction

The permanent disappearance of a species

Evidence of evolution

Scientific proof that explains how life develops

Homologous structures

Similar structure but different function, suggesting shared ancestor

Fossil records

Fossils are found in Strata. Transitional fossils that show change throughout time periods.

Embryology

Embryos at early stages of different species are similar, suggesting a common origin

Microevolution

Species that evolve in a short time, proving natural selection

Genetic evidence

All species have DNA and RNA, replicating in a similar way

Analogous structures

Same function but different structure, not a proof of a common ancestor

Vestigial structures

Structures that do not have a function anymore, remnants of ancestral structures.

Geographical distribution 

Similar species live in the same region, if not it is due to tectonic plate

Isolation

No gene flow between populations

Divergent evolution

Population of the same species start becoming different

Convergent evolution

Unrelated species begin having similar traits

Reproductive isolation

Prevents populations from interbreeding

Prezygotic isolation

Mating is stopped before fertilization

Postzygotic isolation

Offspring reproduction is stopped after fertilization

Temporal isolation

Species mate in different times of the year

Ecological isolation

Species live in different areas

Behavioural isolation

Species have different courting rituals

Mechanical isolation

Species have physical traits working against them

Hybrid Inviability

Hybrid produced but fails to develop

Hybrid infertility

Hybrid produced but will be sterile

Hybrid breakdown

F1 can reproduce but F2 fails to develop properly

Allopatric speciation

Species are separated by a physical barrier which does not allow them to meet

Sympatric speciation

Species do not have a physical barrier

Gene pool

the total collection of all genes, alleles, and genetic information within a reproducing population

Hardy Weinberg principle

Frequencies of different alleles and genotypes within a population will remain constant through time, as long as there are no evolutionary influences present