L2: Evidence of Evolution

Lecture 2 Evidence of Evolution Biol 1407

The process of gradual changes in all forms of life (over generations)

Evolution

“to come from (something/one) with changes”

“Descent with modification”

A process in which organism with favorable traits are more likely to survive and reproduce

Natural Selection

humans imposing a trait on an organism; breeding on an organism that is influenced by human

Artificial Selection

Galapagos Island, Peppered Moths

Examples of Natural Selection

Dogs, Crops, Farm

Examples of Artificial Selection

(selected by humans) favoring individuals with certain phenotypic traits; leads to evolutionary change

Artificial selection operates by

Wild plants or animals are tamed and selectively bred for humans purposes

Domestication

Artificial selection results can be seen in a ____ period of time

short

Direct evidence that evolution has occured

Fossil record

Preserved remains of once-living organisms

Fossils

Amber, siberian permafrost, dry caves, and rocks

Preservation methods

Amber

Tree sap

(Siberian) Permafrost

frozen ground

Why dry caves?

Fungi likes humid places; fungi is a decomposer that will decay any remains of organisms

Most bodies _______ or are ________

decay, eaten

If fossils do form, they are either covered by _______ or worn away by _______

rocks, erosion

Only a ______ fraction are fossilized

small

Can determine the age of fossils

Radiometric dating

What does radiometric dating utilizes to determine the age of fossils?

Isotopes

There are _____ in fossil records

Gaps

Why are there gaps in fossil records?

Fossils are rare

Reveal evidence of evolutionary connections among lineages by comparing the structure of bodies of different species

Comparative morphology

common derivation

Homologous Structures

Different types of an embryo are often similar early on, but as they mature, they appear as what they are supposed to be

Embryonic Development

key regulatory genes or proteins that have a signficant infuence controlling the activity of other genes

Master regulators

Structures with apparent function with our ancestors, but no function in today’s world.

Vestigial structures

Appendix, Tailbon (Coccyx), Wisdom Teeth

Examples of vestigial structures

accumulate independently in the genomes of separate lineages

Neutral mutations

The number of difference among the DNA of different lineages; comparing amino acid sequences

Molecular clock

The fewer the difference

More recent ancestor

The bigger the difference

More distant ancestor

split; separate

Diverge

study of geographic distribution of species

Biogeography

Unrelated organisms independently evolve similar traits or characteristics in response to similar environmental (pressures)

Convergent evolution

Features with similar functions in different, but do not share a common evolutionary origin

Analogous Structures