Bio Unit 3 (evolution)

extinct

describes a species that has compleatly disappeared from earth

adaptation

a structure behaviour or physiological process that helps an organism survive and reproduce in a particular environment

mimicry

a structural adaptation in which a harmless species resembles a harmful species in coloration or structure

variation

differences

mutation

any event that changes genetic structure; any alteration in the inherited nucleic acid sequence of the genotype of an organism

selective advantage

genetic advantage that improves an organisms chance of survival, usually in a changing advantage

natural selection

the process by which characteristics of a population change over many generations as organisms with heritable traits survive and reproduce, passing their traits to offspring

selective pressure

environmental conditions that select for certain characteristics of individuals and select against other characteristics

fitness

the relative contribution an individual makes to the next generation by producing offspring that will survive long enough to reproduce

artificial selection

selective pressure exerted by humans on populations in order to improve or modify particular desirable traits

biotechnology

the use of technology and organisms to produce useful products

monoculture

the cultivation of a single crop

paleontology

the study of aincent life through the examination of fossils

catastrophism

the idea that catastrophies such as floods, diseases, and droughts periodically destroyed species living in a particular region, allowing species from neighbouring regions to repopulate the area

uniformitaeianism

Charles Leyll's throry that geological processes operated at the same rates in the past as they do today

Georges-Lewis Leclarc, Comte de Bouffon

- noted similarities between humans & apes
- earth had to be older than 6000 years
-

Mary Anning

- Family collected fossils
- Helped discover the first specimens of an ichthyosaurus and
plesiosaur
- Her findings, contributions and knowledge were belittled
because she was not formally educated and a female

Georges Cuiver

- Founded vertebrate paleontology
- Developed the ability to reconstruct organisms from individual
parts based on patterns and proportions
- Confirmed Anning’s fossils as genuine
- Didn’t believe that lifeforms could evolve
- From his comparative studies of mummified cats and modern
cats (they were the same)
- Established extinction as a fact

Mass extinction

>50% of all species become extinct in a short time period ~ 2 million years

Charles Lyell

- Rejected catastrophism
- Rock cycle was driven by subterranean heat
- Theory of uniformitarianism
- Geological processes are slow and continuous, not catastrophic and they occur at a constant rate
- Over long periods substantial change may occur
- It works too slowly for us to perceive

Stabilizing selection

natural selection that favours the intermediate phenotypes and acts against extreme variants

Disruptive selection

natural selection that favours the extremes of a range of phenotypes rather than intermediate phenotypes; this type of selection can result in the elimination of intermediate phenotypes

directional selection

natural selection that favours the phenotyoes at one extreme over another, resulting in the distribution curve of phenotypes shifting in the direction of that extreme

inheritance of acquited characteristics

the idea that characteristics acquired during an organism's lifetime can be passed on to its offspring

theory of evolution by natural selection

a theory explaining how life las changed, and continues to change, during earths history

evolution

the process of genetic change in a population over time

Survival of the fittest

the idea that the organisms that are the fittest leave the most offspring, so those organisms win the struggle for survival

descent with modification

Darwins theory that natural selection does not deomonstrate progress, but merely results from a species ability to survive local conditions at a specific time

fossil record

the remains and traces of past life that are found in sedimentart rock, it reveals the history of life on earth and the kinds of organisms that were alive in the past

transitional fossil

a fossil that shows intermediary links between groups of organisms and shares characteristics common to two now seperate groups

vestigial structure

a structure that is a reduced version of a structure that was functional in the organism's anscestors

biogeography

the study of the past and present geographical distribution of species populations

homologous structures

structures that have similar structural elements and origin but may have a different function

analogous structures

structures of organisms that do not have a common evolutionary origin but perform similar functions

embryology

a branch of science that is related to the formation, growth, and development of embryo

gene flow

the net movement of alleles from one population to another due to the migration of individuals

non-random mating

mating among individuals on the basis of mate selection for a particular phenotype or due to inbreeding

genetic drift

the change in frequencies of alleles due to chance events in a breeding population

founder effect

a change in a gene pool that occurs when a few individuals start a new isolated population

bottleneck effect

changes in gene distribution that result from a rapid decrease in population size