CH 18: Intro to Darwinian Evolution

What is the biggest problem with evolution?

Not everyone believes in it

Who proposed that all species currently living on our planet arose from earlier ones by a process of gradual evolution?

Charles darwin

Evidence of evolution includes…

fossils, biogeography, comparative anatomy

Evolution is the cornerstone of biology because it links…

all life sciences into a unified body of knowledge

What is evolution?

The accumulation of genetic changes within populations over time

What is a population?

A group of individuals of one species that live in the same geographic area at the same time

What is a species?

an example?

A group of similar organisms that are capable of interbreeding with one another

ex: cross donkey & female horse = mule

Microevolution

an example?

the minor evolutionary changes of populations, usually viewed over generations

ex: pesticide resistance

Macroevolution

an example?

the major evolutionary events usually viewed over a long period, such as the formation of different species from common ancestors

ex: modified limbs/wings

Evolution of pesticide resistance in insects and other pests is an example of evolution in….

agriculture

Rapid evolution of disease causing bacteria and viruses is an example of evolution in…

medicine

Uses evolutionary principles of population genetics for rare and endangered species

conservation management

Evolution of micro-organisms in polluted soils for clean-up

bioremediation

Who visualized organisms as “moving toward a more perfect state?

Aristotle

Who correctly interpreted fossils as the remains of once existing animals that had become extinct?

Leonardo da Vinci

Who suggested that organisms pass traits they acquired during their lifetimes to their offspring?

Jean Baptiste de Lamarck

Who collected and cataloged thousands of plant and animal specimens and kept notes of his observations?

Darwin

During his exploration, Darwin noticed similarities between ________ & ________ of the ___________ and those of South America, and saw differences in ___________ & _______ from one island to the next

animals & plants, Galapagos, reptiles & birds

Darwin found that many varieties of _______ & ________ could be developed in just a few generations by ____________________

plants & animals, artificial selection

Artificial Selection

human selection of breeding pairs to produce favorable offspring

Darwin studied Thomas Matthus, who suggested that…

inherited variations favorable to survival tend to be preserved, while unfavorable ones are eliminated

Adaptation

an evolutionary modification that improves the chances of survival and reproductive success in a given environment

Who was the British naturalist who studied plants and animals of the Malay Archipelago that arrived at the same conclusion at the same time as Darwin?

Alfred Russel Wallace

What are Darwins four observations of evolution by natural selection

Variation, Overproduction, Limits on population growth, Differential reproductive success

Variation

Individuals in a population exhibit variation in traits; some improve an individual’s chances of survival and reproductive success - others do not

Overproduction

In every generation each species has the capacity to produce more offspring than can survive

Limits on population growth

Organisms compete for limited resources, not all survive to reproduce

Differential reproductive success

Individuals with the most favorable combination of characteristics are more likely to survive and reproduce

Over time, enough changes may accumulate in geographically separated populations (often with slightly different environments) to produce ______________

new species

The modern synthesis

explains Darwins observation of variation among offspring in terms of mutation

Natural selection appears to be a more important agent of evolutionary ________ than _________

change, chance

Fossils are….

-are dated by….

remains typically left in sedimentary rock by previously existing organisms

-relative positions in sedimentary rock

Fossil formation requires that..

an organism be buried under conditions that slow or prevent the decay process

The fossil record is biased toward ________________________ and the few terrestrial habitats conductive to fossil formation

aquatic organisms

Another reason for bias in the fossil record is that organisms with ______ body parts are more likely to form fossils than those with ______ body parts

hard, soft

Using organisms from different geologic ages, scientists can sometimes infer evolutionary relationships, meaning that…

some fossils provide direct evidence of the origin of new species from pre-existing species

Index fossils

organisms that existed for a short geologic time but were preserved as fossils in large numbers over large geographic areas

Carbon-14

dates the carbon remains of anything that was once living

Biogeography is the study of…

the past and present geographic distribution of organisms

• Darwin observed that species found on ocean islands tend to resemble species of the nearest ___________, even if the environment is different (mainland to mainland=similarities)

• Darwin also observed that species on ocean islands do not tend to resemble species on ______ with similar environments in other parts of the world (island to island=differences)

• mainland

• islands