Evolution Flashcards
Evolution
change in allele frequencies in a population
Microevolution vs. Macroevolution
changes in a single gene pool versus appearances of major evolutionary development or new species
Anagenesis or Phyletic Evolution
occurs when one species replaces another
Cladogenesis or Branching Evolution
occurs when a new species branches out from a parent species
Evidence for Evolution: The Fossil Record
Paleontology reveals the existence of species that have become extinct or have evolved into other species. Also, scientists discovered transitional forms that turn into modern animals. Radioactive aging and half-lives are used to age things.
Evidence for Evolution: Comparative Anatomy
Homologous, Vestigial and Analogous structures contribute to the understanding of anatomical structures and relationships.
Homologous Structures
Structures that share bone structure but vary in function. Ex. wing of bat, lateral fin of whale, and human arm
Analogous Structures
Structures that have the same function although the similarity is superficial. Ex. bat wings and fly wing
Vestigial Structures
Structures that do not sere a function although they are still around. Ex. pelvic bone of snake
Comparative Biochemistry
Organisms with a common ancestor have common biochemical pathways. The more closely related organisms are the more similar their biochemistry is. Explains testing on animals.
Comparative Embryology
Organisms with a common ancestors go through similar stages in their embryonic development, All vertebrate embryos go through stages in which they have gills.
Molecular Biology
All aerobic organisms contain cells that carry out aerobic respiration and contain the polypeptide cytochrome C. Comparing this polypeptide shows which organisms are most closely related.
Biogeography
Continental drift states that about 200 m.y.a. the continents were locked into Pangea that separated 150 m.y.a.. Studying geographic distribution of living organisms and fossils confirms the continental first theory.
Aristotle - 1
The Scala Nature stated that all life forms can be arranged on a ladder of increasing complexity each with their own rung of which humans are at the top. The species are permanent and do not evolve.
Carolus Linnaeus - 2
Specialized in taxonomy and named/classified organisms. He developed the naming system called the binomial nomenclature. In this system every organisms has a name consisting of a genus and species.
Cuvier - 3
Studied fossils and realized that each stratum of Earth is characterized by different fossils. He believed that a series of catastrophes were responsible for the changes in the organisms on Earth. He oppose evolution.
James Hutton - 4
The theory of gradualism stated that Earth had been molded by gradual changes not violent, quick ones. The effects of wind, weather and geologic changes were those that creating canyons and ranges. His theory came from the idea that the Earth had a long history.
Lyell - 5
Geologist that stated that geological changes result from slow, continuous actions. He believed the Earth was older than 6,000 years.
Lamarck - 5
Contemporary of Darwin who developed theories of evolution. His theory relies on the ideas of inheritance of acquired characteristics and use and disuse. He stated that individual organisms change in response in their environment.
Wallace - 6
A naturalist author that discussed the idea of natural selection, identical to Darwin.
Darwin - 7
Naturalist and author that worked out the theory of natural selection and descent with modification as the mechanism for how populations evolve. On the Origin of Species was published about his work.
Darwin’s Theory of Natural Selection
- Populations grow exponentially and overpopulate to deplete resources.
- Overpopulation results in competition and a struggle for existence.
- In any population there is variation and an unequal ability of individuals to survive and reproduce.
- Only best-fit individuals survive and get to pass on their traits
- Evolution occurs as advantageous traits accumulate in the population.
How insects become resistant?
Some insects are resistant to a particular chemical insecticide and have a selective advantage. Over time, the proportion of individuals with longer necks increase.
Five Types of Selection
stabilizing, diversifying, directional, sexual, and artificial
Stabilizing Selection
Eliminates the extremes and favors the more common immediate forms. In humans birth weight in the 6-8 pound range. In starlings, birds with 5 eggs have more young survive than birds with more.
Disruptive/Diversifying Selection
Increases the extreme types in a population at the expense of the intermediate forms. Results in balanced polymorphism.
Balanced Polymorphism
one population is divided into two distinct types; over a great length of time this may result in the formation of two new species
Directional Selection
one phenotype replaces another in the gene pool
Directional Selection: Peppered Moths
Until 1845, most peppered moths were light and few were dark. Due to the pollution in the industrial regions dark color frequency increased because they could camouflage better.
Directional Selection: Antibiotics
Bacteria appeared that were resistant to antibiotics and are transferred through plasmids which can spread and cause antibiotic resistance.
Sexual Selection
Selection based on secondary sexual characteristics related to competing for and attracting mates.
Sexual Dimorphism
difference in appearance between males and females