What is Evolution??What is Evolution??Evolution is a theory based on substantial Evolution is a theory based on substantial evidence.evidence.

DefDef: All the changes that have formed life : All the changes that have formed life on earth from its earliest beginnings to the on earth from its earliest beginnings to the diversity that characterizes it today.diversity that characterizes it today.

Pioneers of evolution includePioneers of evolution include::

Darwin, Malthus, Lamarck, Lyell, WallaceDarwin, Malthus, Lamarck, Lyell, Wallace

Malthus (1766- 1834): Population growth Malthus (1766- 1834): Population growth theories theories http://www.blupete.com/Literature/Biographies/http://www.blupete.com/Literature/Biographies/Philosophy/Malthus.htmPhilosophy/Malthus.htm

Lamarck (1744 – 1829): Lamarck developed Lamarck (1744 – 1829): Lamarck developed two laws to explain evolution: the law of use two laws to explain evolution: the law of use and disuse, and the law of inheritance of and disuse, and the law of inheritance of acquired characteristics.acquired characteristics.

http://en.wikipedia.org/wiki/Lamarckhttp://en.wikipedia.org/wiki/Lamarck Lyell (1797 – 1875): Wrote Lyell (1797 – 1875): Wrote Principles of Principles of

Geology- Geology- said “The present is the key to the said “The present is the key to the past”past”

Wallace (1823 – 1923): Biogeography; first to Wallace (1823 – 1923): Biogeography; first to form theory of natural selectionform theory of natural selection

Lamarck Law 1:Lamarck Law 1:

(Use and disuse) (Use and disuse) In every animal which has not In every animal which has not passed the limit of its development, a more passed the limit of its development, a more frequent and continuous use of any organ frequent and continuous use of any organ gradually strengthens, develops and enlarges gradually strengthens, develops and enlarges that organ, and gives it a power proportional to that organ, and gives it a power proportional to the length of time it has been so used; while the length of time it has been so used; while the permanent disuse of any organ the permanent disuse of any organ imperceptibly weakens and deteriorates it, and imperceptibly weakens and deteriorates it, and progressively diminishes its functional capacity, progressively diminishes its functional capacity, until it finally disappears.until it finally disappears.

Lamarck Law 2:Lamarck Law 2: (Inheritance of acquired characteristics) (Inheritance of acquired characteristics) All the All the

acquisitions or losses wrought by nature on acquisitions or losses wrought by nature on individuals, through the influence of the individuals, through the influence of the environment in which their race has long been environment in which their race has long been placed, and hence through the influence of the placed, and hence through the influence of the predominant use or permanent disuse of any predominant use or permanent disuse of any organ; all these are preserved by reproduction organ; all these are preserved by reproduction to the new individuals which arise, provided to the new individuals which arise, provided that the acquired modifications are common to that the acquired modifications are common to both sexes, or at least to the individuals which both sexes, or at least to the individuals which produce the young.produce the young.

So who was Darwin, So who was Darwin, anyway, and why do we anyway, and why do we care?care? Darwin relied on years of close observations Darwin relied on years of close observations

and data to develop his theories on evolution.and data to develop his theories on evolution. Most well known for descriptions of Galapagos Most well known for descriptions of Galapagos

Finches. Finches. He concluded that birds were adapting to their He concluded that birds were adapting to their

environment by having different beak sizes for environment by having different beak sizes for their available food source.their available food source.

Revolutionized the theory of evolution at a very Revolutionized the theory of evolution at a very controversial time in history.controversial time in history.

Darwin proposed that species were evolving by Darwin proposed that species were evolving by process of process of natural selectionnatural selection – a process by – a process by which organisms best suited to their which organisms best suited to their environment reproduce more successfully than environment reproduce more successfully than other organisms.other organisms.

For natural selection to occur, has to be some For natural selection to occur, has to be some certainties about the population:certainties about the population:

- Organisms have to reproduce- Organisms have to reproduce

- Has to be variation within the population- Has to be variation within the population

- Traits have to have a genetic basis- Traits have to have a genetic basis

- Trait provides advantage to organism- Trait provides advantage to organism

Some Vocab. To Know…Some Vocab. To Know… AdaptationAdaptation: an inherited trait that : an inherited trait that

increases an organism’s chance of increases an organism’s chance of survival in a particular environment.survival in a particular environment.

FitnessFitness: the ability of individuals to : the ability of individuals to survive to pass on their genes.survive to pass on their genes.

PopulationPopulation: interbreeding single-species : interbreeding single-species group.group.

SpeciesSpecies: a group of organisms of a single : a group of organisms of a single type that are capable of producing fertile type that are capable of producing fertile offspring.offspring.

Which moth Which moth started to started to appear after appear after the industrial the industrial revolution?revolution?

Other evidence…Other evidence…

FossilsFossils AnatomyAnatomy EmbryologyEmbryology BiochemistryBiochemistry

http://www.sciohio.org/Image97.jpghttp://www.sciohio.org/Image97.jpg

For Homework…For Homework…Answer the following questions. Be ready to Answer the following questions. Be ready to

discuss your answers the beginning of discuss your answers the beginning of class:class:

1.1. Why is there variation among all living Why is there variation among all living organisms? Provide two concrete organisms? Provide two concrete examples as to how this helps species examples as to how this helps species survive. survive.

2.2. Name one important person besides Name one important person besides Darwin who helped influence the theory of Darwin who helped influence the theory of evolution. What were some of their evolution. What were some of their contributions and during what time period contributions and during what time period did they occur?did they occur?