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unit 7 chp 19 Cheat Sheet by

unit 7 chp 19 part 1

3 KEY OBSERV­ATIONS

* the striking ways in which organisms are suited to their enviro­nment
* the many shared charac­ter­istics (unity) of life
*the rich diversity of life

INFLUE­NCING DARWIN

Fossils and Geology
-Cuv­ier:
catast­rophism
-Hut­ton:
gradualism
-Lye­ll:
unifor­mit­ari­anism

ADAPTA­TIONS

- charac­ter­istics of organisms that enhance their survival and reprod­uction in specific enviro­nments
- "can the origin of new species and the adaptation of species to their enviro­nment by closely related proces­ses­?"

NATURAL SELECTION

- differ­ences between the 13 species of finches that Darwin collected were adapta­tions to the food available in their habitat
- these adaptions arise by natural selection, a process where indivi­duals with certain inherited charac­ter­istics leave more offspring than indivi­duals with other charac­ter­istics

ADAPTATION FINDINGS

- natural select­ion:
a process in which indivi­duals that have certain heritable traits survive and reproduce at a higher rate than other indivi­duals because of those traits
- over time, natural selection can increase the match between organisms and their enviro­nment
- if an enviro­nment changes, or if indivi­duals move to a new enviro­nment, natural selection may result in adaptation to these new condit­ions, sometimes giving rise to new species in the process

KEY EVIDENCES OF EVOLUTION

-direct observ­ation of evolut­ion
MRSA and Soapberry bug
- homo­logy
similarity in organisms resulting from common ancestry
- the fossil record
- Biog­eog­raphy
the geographic distri­bution of species
 

DESCENT WITH MODIFI­CATION

- Darwin defined evol­ution as descent with modifi­cation proposing that Earth's many species are descen­dants of ancestral species that were very different from those alive today
- evolution can also be defined more narrowly as a change in the genetic compos­ition of a population over time

LAMARCK: 1809 THEORY

- based his theory of evolution on observ­ations of fossils
-2 main principles
1.) use and disuse
 
2) inheri­tance of acquired charac­ter­istics
- thought that evolut­ionary change was driven by organisms drive to increase complexity

DESCENT WITH MODIFI­CATION

- all organisms are related through descent from a common ancestor that lived in the remote past
- explains unity of life!
- over time, descen­dants of that common ancestor have accumu­lated diverse adapta­tions that allows them to survuve and reproduce in specific habitats
- this descent with modifi­cation has lead to the rich diversity of life we see today!

EVOLUTION BY NATURAL SELECTION

1.) indiv­iduals do not evolve
a population is the smallest group that can evolve over time
2.) Natural selection can act only on heritable traits, traits that are passed from organisms to their offspring. Charac­ter­istics acquired by an organism during its lifetime may enhance its survival and reprod­uctive success, but there is no evidence
3.) enviro­nmental factors vary from place to place and from time to time. A trait that is favorable in one enviro­nment may be useless or even detrim­ental in another enviro­nment
 

EVOLUTION: both pattern & process

- the pattern of evolut­ionary change is revealed in observ­ations about the natural world
- the process of evolution consists of the mechanisms that have produced the diversity and unity of living things

CHARLES DARWIN (1809-­1882)

- naturalist on the HMS Beagle (1831)
- Chart South American coastline
- Galapagos Islands

DARWIN'S OBSERV­ATIONS

- plants and animals of South America are very different from those in Europe
- Animals that lived on islands resembled those that lived on the mainland, but were different

BRANCHING IN EVOLUTION

- darwin viewed the history of life as a tree with multiple branches
- closely related species share the same line of descent until they diverge from each other

ARTIFICAL SELECTION

humans have modified a variety of domest­icated plants and animals over many genera­tions by selecting indivi­duals with desired traits as breeding stock

KEY POINTS OF NATURAL SELECTION

- natural selection is a process of editing, not a creative mechanism
- a drug does not create resistant pathogens; it selects for resistant indivi­duals that are already in the population
- natural selection depends on time and place
- what is beneficial one place can be detrim­ental in another place
 

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