Unit V: Darwin’s Voyage and the Theory of EvolutionMs. BuechlerInt.Sci. 4/Biology

EW 3/27What do you know about Charles

Darwin? What theory did he come up with? What’s the name of famous island that he made many of his observations that lead to this theory?

Bill Nye: EvolutionOld School Bill Nye the Science Guy: Evolu

tion

Bill Nye Great Discoveries: Evolution

Darwin’s Voyage Book Resources Life and Times of Ch

arles Darwin

http://topics.nytimes.com/topics/reference/timestopics/people/d/charles_robert_darwin/index.html

http://www.aboutdarwin.com/voyage/voyage04.html

http://evolution.berkeley.edu/evolibrary/article/0_0_0/history_14

Videos Darwins' Voyage

Revisted in 2014 Darwin v. Lamarck's

view of Natural Selection

Vocab for Darwin Book Adaptive Radiation-

when a species derived from a common ancestor (like with Darwin’s Finches) adapts to the environment by natural selection, causing a change in the gene pool of a population.

Evolution- biological change in a population’s gene pool over time…

Natural Selection- process in which organisms adapt to their environment:◦ Species tend to produce more

offspring than what will survive.◦ Variations are found among

individuals of a species.◦ Some variations enable members

of a population to survive and reproduce better than others… they are better suited for survival in the given area.

◦ Over time, offspring of individuals with helpful variations make up more and more of a population… they have adapted to the environment.

Vocab for Darwin Book Selective Pressures- changes in

resources, mates, and/or environment that lead to a change in allele frequency in a population.◦ Ex> change in climate and the

wooly mammoth to modern elephants

Species- smallest level of classification, in which organisms can mate and produce viable offspring.

Speciation- formation of a new biological species

Variation- unique qualities of individuals of the same species in a given population.

Acquired Characteristics- traits that develop after birth… like Lamarck’s explanation of how giraffes got long necks.

Mutations- permanent changes in the DNA

Adaptation-“An alteration or adjustment in structure or behaviors by which a species or individual improves its condition in relationship to its environment”

Reproductive Isolation- physical or geographical barriers that restrict the interbreeding of populations.

Natural Selection: Wallace, Lamarck & Darwin

EW 4/1

What year did Darwin visit the Galapagos Islands?

When was his paper “Voyage of the Beagle” published?

3 Influential Scientists Perspective’s on Natural SelectionInto to Theory of Evol

ution.doc

http://evolution.berkeley.edu/evolibrary/article/0_0_0/history_14

Lamarck Similar species arose from common ancestor organisms change

over time Acquired trait= not determined by genes, but arises during an

organisms lifetime in response to behavior and or experiences Acquired traits are then passed onto offspring

Wallace1st to propose the theory

of “Natural Selection”◦ Organisms best suited to

their environment reproduce more successfully than other organisms

◦ “Intelligent evolution” is a theory of common descent based upon natural selection strictly bounded by the principle of utility

Wallace recognized that useful variations allowed organisms to better survive in their environment those successful variations occurred with greater and greater frequency in the population (increase gene frequency)

Darwin

Descent with Modification via Natural SelectionNewer organisms are

modified decedents of older species

Natural Selection causes these modifications primary mechanism changing organisms from their origin to a species well adapted to its environment

Summary of Theories on Natural Selection

Lamarck Wallace Darwin

Driving

Mechanism for Changing Traits

Acquired TraitsOrganisms changed in response to their environment/habitat

Natural Selection- favorable traits are passed onto offspring to increase their chances of survival

Descent with Modification via Natural Selection- Newer organisms are modified descendants of a few original organisms this modification occurs via Natural Selection

Do Species Change?

Yes- individual organisms can

change within their lifetime

Yes- Populations change over time

Yes- Populations change over time

End Result: Where to

species come from?

Common Ancestor? Species created based on environment

Common Ancestor- but a product of their environments

Common Ancestor all species from one or more original organisms

Principles of Natural Selection

Organisms produce more offspring that can survive.

Variations are found among individuals of a species.

Some variations enable members of a population to survive and reproduce better than others.

Over time, offspring of individuals with helpful variations make up more and more of a population