Major Contributions (w/o Darwin)
Scottish geologist, living in the 1800s, who built upon past work by stating that the gradual mechanisms that created our world's present geographical features are still operating on it currently and changing it at the same, slow pace they always have. (LO1)
Lyell
The famous trip that Darwin went on that led to his ideas about evolution. (LO3)
Voyage of the Beagle
What is natural selection? (LO5)
A process that results in the adaptation of an organism to its environment by means of selectively reproducing changes in its genotype, or genetic constitution.
What are four types of natural selection? (LO12)
Directional selection, disruptive selection, stabilizing selection, and balancing selection.
What is relative fitness? (LO8)
The survival and/or reproductive rate of a genotype (or phenotype) relative to the maximum survival and/or reproductive rate of other genotypes in the population.
French biologist, living in the late 1700s and early 1800s, who was the first to propose a mechanism by which evolution might occur. Although this mechanism was later found to be incorrect, he was the first to emphasize how the environment plays a key role in evolution and that the environment can help explain changes in organismal forms seen in the fossil record. (LO1)
Lamarck
Out of all the places Darwin visited, what was the most influential to the development of his theory of evolution? (LO3)
The Galapagos islands
What is required for natural selection to take place? (LO5)
Reproduction, heredity, variation in fitness or organisms, and variation in individual characters among members of the population.
Distinguish between natural selection and artificial selection. (LO10)
Natural selection is a nature made selection, while artificial selection is a man made selection.
Explain how relative fitness can vary with environment. (LO9)
A less harsh environment with a slow changing atmosphere might be more beneficial to the population in it, because it would give them more time for adaptation to occur.
Greek philosopher living in 300 BCE, who believed species did not change through time. He arranged organisms into a hierarchy based on increasing complexity, which he called the scale of nature. (LO1)
Aristotle
Explain what Darwin saw on the Voyage of the Beagle that led to his idea that species are related to another species, modern species arose from ancestral species, and organisms are well suited to their environments. (LO3)
He noticed that the finches on the island were similar to the finches from the mainland. According to this idea the pattern of finch would only make sense if the Galapagos Islands had long ago been populated by birds from the neighboring mainland. Each finch also showed certain characteristics that helped them to gather food more easily in their specific habitat.
How does natural selection act on individuals to ultimately change populations? (LO5)
Natural selection works to change populations by favoring some variations in individuals and working to eliminate other variations in individuals (basically a culling process).
Distinguish between analogous and homologous traits. (LO14)
Homologous structures are structures that evolve in living organisms that have a common ancestor. Analogous structures are those that evolve independently in different living organisms but have a similar or the same function.
What is adaptation and what is an example? (LO7)
Adaptation is the process by which a species becomes fitted to its environment; it is the result of natural selection's acting upon heritable variation over several generations. An example of adaptation is how some plants have adapted to life in dry, hot, deserts.
British naturalist, living in the 1800s, who worked on islands in the South Pacific and independently developed a hypothesis of natural selection that was strikingly similar to Darwin's own hypotheses. He sent his ideas to Darwin, which gave Darwin the push he needed to publish his work before he was "scooped". (LO1)
Wallace
State Darwin's two observations and his two inferences from his time on the Galapagos. (LO4)
His observations were: Individuals in a population vary in their heritable characteristics, and organisms produce more offspring than the environment can support.
His inferences from these observations were: Individuals that are well suited to their environment tend to have more offspring than other individuals (relative fitness), and over time, favorable traits accumulate in the population (meaning the population evolves).
What are the roles of mutations and the environment in natural selection? (LO5)
Mutations can be harmful, neutral, or sometimes helpful, resulting in new advantageous traits. When mutations occur in germ cells (egg and sperm) they can be passed onto offspring. If the environment changes rapidly, some species may not be able to adapt fast enough through natural selection.
Distinguish between convergent and divergent evolution. (LO15)
Convergent evolution involves unrelated species that develop similar characteristics over time, while divergent evolution involves species with a common ancestor that changes to become increasingly different over time.
Describe circumstances in which an organisms relative fitness would increase and decrease. (LO8)
Increase circumstance- A trait that increases ability to survive, but has no effect on reproduction in an already fertile species, increases fitness because the species could reproduce and pass the trait onto their offspring.
Decrease circumstance- A trait that increases ability to survive, but makes an individual sterile, decreases fitness because the organism cannot produce offspring to carry on the trait.
Swedish physician living in the 1700s, who developed the two part naming system for species that we still use today (i.e. Genus named, followed by species name). He also created a classification system, in which he grouped organisms based on their similarities. (LO1)
Linnaeus
Compare and contrast Lamarck's, Wallace's, and Darwin's ideas on evolution. (LO1)
Darwin argued that human evolution could be explained by natural selection, with sexual selection as a significant supplementary principle. Wallace always had doubts about sexual selection, and ultimately concluded that natural selection alone was insufficient to account for a set of uniquely human characteristics. The difference between Darwin and Lamarck is that Darwinism recognizes the battle for life and survival of the fittest while Lamarckism does not recognize the struggle for life and survival of the fittest.
Distinguish between evolution and natural selection. (LO6)
Evolution is a gradual change in the inherited traits of a population over many generation, while natural selection is a mechanism where the members of a population best suited to their environment have the best chance of surviving to pass on their genes.
Explain why natural selection can't make perfect individuals/organisms. (LO11)
Natural selection can only select on existing variation in the population. It does not create anything from scratch. Thus, it is limited by population's existing genetic variance and whatever new alleles arise through mutation and gene flow.
Distinguish between directional, disruptive, stabilizing, and balancing selection. (LO12)
Directional selection- Individuals at one end of the phenotypic range survive or reproduce more successfully than do other individuals.
Disruptive selection- Individuals on both extremes of a phenotypic range survive or reproduce more successfully than do individuals with intermediate phenotypes.
Stabilizing selection- Intermediate phenotypes survive or reproduce more successfully than do extreme phenotypes.
Balancing selection- Maintains two or more phenotypic forms in a population.