BIOL 112: Exam 1

What is evolution?

The change in a population’s genetic composition over generations

What is the correction to the misconception: “Evolution is just a theory”?

It is supported by extensive scientific evidence

What is the correction to the misconception: “Individuals evolve”?

The smallest unit of evolution is a population

What is the correction to the misconception: “An organism can evolve during its lifetime”?

An organism cannot evolve during its lifetime. Evolution occurs over multiple generations.

What is the correction to the misconception: “Evolution explains the origin of life”?

It focuses on genetic variation that occurred after origin

What is the correction to the misconception: “Organisms evolved on purpose”?

Organisms evolve in response to a change in their environment. They cannot influence their own evolution.

What is the correction to the misconception: “Species are always evolving into “higher” or “better” beings”?

Evolution is not goal oriented. It is a reaction mechanism.

What is the correction to the misconception: “Evolution creates new forms of life by dramatic mutations”?

Evolution changes organisms from generation to generation as mutations are passed down to offspring

What is the correction to the misconception: “Evolution is a completely random process”?

Evolution ensures that only advantageous traits that increase the likelihood to survival are passed down.

What was Aristotle’s view on life (Western ideas)?

There is a fixed ideal species and a scala naturae

What were non-Western cultures’ view on life?

Natural philosophies instead of science

What was the view on life in the Age of Reason?

Emphasis on scientific inquiry and observation

What was Carl Linnaeus known for?

Binomial naming system

What was James Hutton known for?

Gradualism

What is gradualism?

The theory that significant changes are the result of slow, gradual processes that occur over time rather than instantaneous, dramatic change

What was Charles Lyell known for?

Uniformitarianism

What is uniformitarianism?

The theory that the same natural laws and processes that operate in the universe today have operated in the same manner throughout Earth's history

What was Lamarck known for?

Linking evolution to adaptation

What is an adaptation?

An inherited feature that helps an organism’s survival and reproduction in its present environment.

Which of Lamarck’s ideas did Darwin reject?

Characteristics acquired in an organism’s lifetime can be passed down to offspring

What are the 2 main ideas of Darwin’s theory?

Descent with modification and natural selection

What is descent with modification?

All present life is related from a common ancestor in the past

What is natural selection?

“Survival of the fittest”, reproduction of individuals with favorable genetic traits that survive environmental change because of those traits, which leads to evolutionary change

Which scientist agreed with Darwin in his lifetime?

Alfred Wallace

What are the 4 observations that support the idea that natural selection is the mechanism for evolution?

1. Heritable variation exists in most species

2. More offspring are produced than can survive, so there is competition for resources

3. There is unequal reproductive success among individuals

4. Those heritable, favorable traits accumulate over vast time

What is essential for evolution by natural selection?

Genetic variation

What is some evidence of evolution?

Direct observation, fossil record, homologous structures and vestigial structures, convergence, biogeography, molecular biology

What does the fossil record show?

Transition of adaptive forms over time from one ancestor to the present day organism

What are homologous structures?

Forms related by common ancestry but have different functions (e.g. human arm, dog leg, bird wing, whale fin)

What is another name for homologous structures?

Divergent evolution

What are vestigial structures?

Remnants of ancestral structures with no present adaptive function

What are analogous structures?

Biological features in different species that serve the same function and were not the result of a common ancestor (e.g. torpedo shape for swimming in dolphins, seals, and sharks)

What is convergence?

Unrelated species have similar adaptations due to being under similar environmental conditions

What is biogeography?

The distribution of species corresponds to geographic history

What is a species?

A taxonomic group of organisms that can interbreed and produce viable, fertile offspring

What is the morphological species concept based on?

Physical similarities and differences

What is the ecological species concept based on?

Organisms have adapted to a specific set of resources (aka ecological niche)

What is the phylogenetic species concept based on?

Evolutionary ancestry and genetic data

What is the biological species concept based on?

Reproductive isolation

Elaborate on the biological species concept.

A species is a set of populations whose members potentially interbreed in nature to produce fertile, viable young and do not successfully interbreed with other species

Is the biological species concept based on similarity of appearance?

No

Can you apply the biological species concept to asexual reproduction?

No

What is needed in order for speciation to occur?

Reproductive isolation

What is a gene pool?

A collection of all of the variants of genes (alleles) in a species

What is gene flow?

The movement of genetic material

What are the 2 biological barriers?

Prezygotic barriers and postzygotic barriers

What are the 5 prezygotic barriers?

Temporal isolation, habitat isolation, behavioral isolation, gametic isolation, and mechanical isolation

What is temporal isolation?

Species have different breeding schedules

What is habitat isolation?

Members of species do not reproduce because they live in different environments

What is behavioral isolation?

Certain actions or behaviors (or lack of them) prevent reproduction

What is gametic isolation?

Gametes cannot fuse

What is mechanical isolation?

Sexual organs are incompatible

What are the 3 postzygotic barriers?

Hybrid inviability, hybrid sterility, and hybrid breakdown

What is hybrid inviability?

A hybrid offspring is produced but cannot survive development

What is hybrid sterility?

2 different species can produce viable offspring, but that offspring cannot reproduce

What is hybrid breakdown?

2 individuals in the first hybrid generation produce offspring, but that 2nd hybrid generation is weak and/or sterile

What is microevolution?

Changes over time in allele frequencies in a population

What is macroevolution?

The processes that give rise to new species and more diverse taxonomic groups

What evolution process increases diversity?

Microevolution with speciation