ap bio chapter 22

On the Origin of Species

Darwin; many modern species are decendents of ancestral species; the mechanism for this evolutionary process is natural selection

Natural Selection

A population can change over generations if individuals with certain heritable traits leave more offspring than others. Result=evolutionary adaptation.

Evolutionary Adaption

the accumulation of inherited characteristics that enhance an organisms ability to survive and reproduce in a specific enviroment.

Evolution

change over time in the genectic composition of a population, also refers to the gradual appearance of all biological diversity

Aristotle

All Living forms could be arranged on a scale, ladder of increasing complexity, later called the "scale of nature" Opposed any concept of evolution and viewed species as fixed and unchanging.

Old Testament

Species were individually designed by God and perfect

Carolus Linnaeus

Swedish Physician and Botanist, founded taxonomy. Grouped similiar species into increasingly general catergories. Similarity between species did not imply evolution but pattern of creation.

Taxonomy

Linnaeus, a system for naming species and classifying species into a heirarchy of increasingly complex organisms. Kingdom, Phylum, Class, Order, Family, Genus, Species

Binomial System

Linnaeus, naming organisms according to genus and species

Darwin's Influence by?

Fossils, Remains, Traces of Organisms from Sedimentary Rocks

Georges Cuvier

developed Paleontology; study of fossils. Documented in Paris Basin---> documented succession of fossil species and found extinction to be common.

Who adopted Catastrophism?

Cuvier------------> speculation that boundaries between strata were due to local floods or droughts that destroyed species. Eventually repopulated by species immigrating from unaffected areas.

James Hutton

Geology= Theory of Gradualism----> Geological changes took place slowly but its a continous process.

Charles Lyell

Theory of Uniformiarinism, geological processes had not changed throughout Earth's history.

Who had influence on Darwin

Hutton and Lyell= Geologic Events are slow than Earth must be older than 6,000 yrs old estimated from Bible. Second, Gradualism can produce substantial change over long period of time.

Jean Baptiste Lamarck

Applied Concept of Gradualism to Biological Evolution Proposed two mechanisms for Evolution..Use and Disuse, Inheritance of Acquired Characteristics. Thought that evolutionary change was driven by innate drive of organisms to increasing complexity.

"Use and Disuse"

Lamarck---------->Parts of the body that are used become larger and stronger whereas parts that are not used dissappear.

Inheritance of Acquired Characteristics

Modifications acquired during ones lifetime can be passed to offspring. BIGGEST Mistake to contribution of Evolution. Larmarck

Alfred Russel Wallace

Young Naturalist also developed Natural Selection Theory

Descent with Modifcation

All organisms are related through descent from a common ancestor that lived in the remote past. Over evolutionary time, the descendants of that common ancestor develop modifications or adaptations that allow them to reproduce in specific habitats.

Ernst Mayer

dissected logic of Darwins Theory into three inferences based on five observations

Observation 1

Population size would increase---> organisms reproduced successfully

Observation 2

Populations tend to remain stable in size except for seasonal fluctuations.

Observation 3

Enviromental Resources are limited. Inference #1---Production of more individuals than enviroment can lead to struggle for existence with only fraction of offspring surviving.

Observation 4

Individuals of a population vary extensively in their characteristics. No two individuals are alike.

Observation 5

Much of this variation is heritable. Inference #2---Survival in the struggle for existence is not random but depends on inherited traits. Inference #3----This unequal ability of individuals to survive and reproduce will lead to a gradual change in population with favorable characteristics accumulating.

Thomas Malthus

influenced Darwin.."overproduction" Human Suffering--disease, famine, was the inescapable consequence of the potential for human populations to increase faster than food supplies and other resources.

Differential Reproductive Success

Organisms with traits favored by the enviroment produce more offspring than do organisms without those traits--results in the favored traits being disproportionately represented in the next generation.

Artificial Selection

modifying a variety of domesticated plants and animals over many generations by selecting individuals with the desired traits as breeding stock.

Darwins Main Idea 1

Natural Selection is differential success in reproduction (unequal ability of individuals to survive and reproduce) results from individuals that vary in heritable traits and their enviroment.

Darwins Main Idea 2

The Product of Natural Selection is the Increasing adaptation of organisms to their enviroment.

Darwins Main Idea 3

If an enviroment changes over time, or if individuals of a species move to a new enviroment, Natural Selection may result in adaptation to the new conditions, sometimes giving rise to a new species in the process.

Evolution Through Natural Selection

Individuals do not Evolve---Natural Selection can act only on heritable traits, traits that are passed from organisms to their offspring (editing mechanism) it cannot create favorable traits It can only act on existing variation----A trait that is favorable in one enviroment may be useless or detrimental in another.

John Endler & David Reznick

Guppies, HIV

Homology

Similarity in characteristic traits from common ancestry. Forelimbs in humans, cats, whales. All have different functions. Not obvious in adults but evident at embryonic development. Anatomical Similarites, Vestigial Organs, Genes and Protein, Genetic Code.

Vestigial Structures

No importance to organism, but had important functions in ancestors. Some are homologous structures.

Analogous Structures

Similiar Function but did not arise the same..wings in insects, wings in bird, wings in bat.

Biogeography

Species tend to be more closely related to other species from same area than to other species with the same way of life that live in different areas.

Fossil Record

Succession of Life Forms is consistent with Descent of Modification