8.1 - evolution scientists

evolution

process by which hereditary changes occur in one or more characteristics within a species over long periods of time

trilobites

Extinct animals with over 15,000 species that lived 515 million years ago; their fossils help scientists study the Cambrian explosion due to their diversity and abundance.

cambrian explosion

over 500m years ago led to sudden increase in diversity of animals

scientific hypothesis

statement that provides one possible answer to a question or one possible explanation to an observation

scientific theory

general statement that explains and makes successful predictions about a broad range of observations

early ideas

based on religion/philosphy that all life has always existed and is unchanged

John Ray

first scientist to carry out studies on natural world and think of similarities and differences between organisms

Linnaeus

• supported ray

Leclerc

• 1st to challenge that life forms were unchanging

• humans and apes

• Earth is old

• suggested species change over time

Mary Anning

• discovered first plesiosaur

• fossil hunter in england

• Cuvier acknowledged her work

Cuvier

• developed science of paleontology

• found each stratum had a unique group of fossil species and the deeper u go, the less similar fossils look to current life on earth

• suggested species could go extinct, as new species appeared and other disappeared in the stratum

• Catastrophism

paleontology

study of ancient life thru examination of fossils

catastrophism

events such as floods, diseases etc.. destroyed species in one region, allowing species in neighbouring areas to then repopulate the region

Lyell

• rejected catastrophism

• uniformitarianism

uniformitarianism

• rate of geological change is no different today than it was in the past

• gradual changes happen over long periods of time and result in substantial changes

Lemarck

• believed that species increased in complexity until they reach perfection

• “inheritance of acquired characteristics”

• use and disuse

inheritance of acquired characteristics

organisms would become better adapted to their environment and then pass this on to their offspring (FALSE)

Use and Disuse

body parts not used would eventually disappear

Charles Darwin expedition

• purpose: map coast of South America

• his observations later became important to his theory of evolution by natural selection

Charles Darwin Observations

• rodents in South America looked different to ones in other continents

• Fossils in South America resembled living animals in south america

• Galapagos species rememble organisms on another south american coastline

• a lot of diversity of species in a small area

• Did artificial selection and knew it was possible for traits to be passed from parent to offspring with many diff combos

Theory of Evolution by natural selection

• believed all life descended from one organism

• Organisms produce more offspring than can survive so organisms must compete for limited resources.

• Individuals of a population vary, and much of this variation is heritable.

• Individuals that are better suited to local conditions survive to produce more offspring.

Survival of the fittest

• Individuals with helpful traits are more likely to survive and pass them on.

• Over time, these traits become more common in the population.

Descent with Modification

Darwin did not use word evolution, instead said this since he believed evolution implied progress

Wallace

Worked with Darwin

Vestigial structures

Body parts that no longer have a clear function but were useful in an organism’s ancestors.