Evidence of Evolution

Fossil record

Fossils provide a record of species that lived long ago and how their traits changed over time.

Derived traits

Newly evolved traits such as feathers

Ancestral traits

More primitive features such as teeth and tails

Homologous structures

Anatomically similar structure inherited from a common ancestor, Similar physical features in organisms but the features serve completely different functions.

Comparative anatomy

Scientists compare the anatomical structure between animals to see if they share a common ancestor

Vestigial structures

Structures that are the reduced forms of functional structures in other organisms

Biochemistry and DNA

When comparing the DNA of one species to another more similarities are found in species that are more closely related

Comparative embryology

Embryos are the early pre-birth stage of an organism’s development. Scientists have seen that embryos in various embryos in various species resemble each other in the beginning.

Direct observation of species change

example: bacteria become resistant to antibiotics

Fitness adaptations

A measure of how much of that trait is passed on to the next generation

Camouflage adaptions

This adaption allows the organism to become almost invisible to predators in their environment

Mimicry adaptations

One species evolves to resemble another species

Who was Charles Darwin and describe his voyage.

Charles Darwin is known as the father of modern day evolutionary theory, He was a naturalist on the HMS beagle, He explored the South America, and South Pacific, including the Galapagos Islands,

What did Charles Darwin collect and take back to Britain?

He collected samples of fossils and live specimens for study.

What did he conclude from his findings? He coined a certain phrase.

He noticed that specimens changed depending on what islands the animals were from and how they survived, he coined the phrase natural selection.

What causes variations among populations?

Variation can be inherited which are passed down from parent to offspring (ex. advantages to survive)

What are the pieces of evidence of evolution?

Fossils, Homologous Structures, vestigial organs, DNA, Embryos, Direct Observation.

Info from our lab, What is the difference between selections?

The difference is in the what characteristics or variations are shown within a population.

Info from our bird beak lab, why is adaptation important?

Without adaptation certain species would be unable to evolve depending on their environments. Ex. without adaptation the finches on the Galápagos Islands would have not been able to survive throughout the drought or the storm which both brought different kinds of food.

Evolution

The change over time

Artificial Selection

The process by which humans choose individual organisms with certain phenotypic trait values for breeding

Natural selection

The process through which populations of living organisms adapt and change

Common ancestor

An ancestral group of organisms that is shared by multiple lineages.

Embryo

The early development stage of an animal while it is in the egg or within the uterus of the mother

Adaptions

The evolutionary process where by ab organism becomes better able to live in its habitat or habitats

Fitness

An organisms ability to pass its genetic material to its offspring

Speciation

When a group within a species separates from other members of its species and develops its own unique characteristics

Reproductive Isolation

A quantitative measure of the effect of genetic differences on gene flow.

Behavioral Isolation

Ex. Different Mating song or dance

Geographic isolation

Separated by Habitat, (ex. Land and water, mountain and valley, tree and grass)

Temporal isolation

Separated by time, (ex. Nocturnal v diurnal, 17-year cicadas)

Directional Selection

Shift to one direction, one extreme or there other is selected

Stabilizing Selection

Intermediate forms of a trait is selected, Most of the population is the average extremes are selected against

Disruptive Selection

Two extreme forms of a trait are selected, Most are one extreme or the other - middle is selected against.

Genetic drift

The change infrequency of an existing gene variant in the population duet random chance

Sexual selection

The process by which individuals compete for access to mates and fertilization opportunities

Allopatric Selection

Occurs when a species separates into two separate groups that are isolate from one another

Sympatric Speciation

The splitting of an ancestral species into two or more reproductively isolated groups without geographical islution of those groups.