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KHS Biology Evolution

Terms in this set (44)

age of the earth
-determined by dating meteors
-4.6 billion years old
origin of life
-between 3.4 and 3.9 billion years ago
-originally single-celled, prokaryotic life in the ocean
Hutton & Lyell
-Geologists who proposed theories of gradualism
-hypothesized the earth is much older than it popularly was held to be
Malthus
-Wrote an essay proposing that organisms reproduce so much that the environment can't support them
Charles Darwin
-Proposed the theory of evolution by natural selection
-Went on a voyage on the HMS Beagle
-Influenced by visit to Galapagos Islands
-wrote "The Origin of Species"
Alfred Wallace
-Proposed the same theory as Darwin and prompted Darwin to quickly publish his book
Jean Baptiste Lamark
Proposed own theory of evolution, including the (mostly incorrect) ideas that:
-organisms tend to strive toward perfection
-traits are enhanced or degrade through use and disuse
-acquired traits can be passed down to offspring
absolute dating
-method of determining fossil age by dating the age of the rock in which they reside by examining radioactive isotopes
relative dating
-method of determining fossil age by comparing the relative positions of fossils in the layers of rock.
Fossil record completeness
-it is not complete because:
1. Fossilization is a rare process only occuring under certain conditions
2. We have not found every fossil
trace fossil
-kind of fossil, such as a footprint, that is indirect evidence of an organism
mold & cast fossil
-kind of fossil involving a hollow space/impression or such a space that has been filled.
replacement fossil
-a fossil showing detail because parts of the organism have been slowly replaced by minerals
petrified fossil
-kind of fossil common for trees involving smaller hollow spaces being filled with minerals
amber fossil
-kind of fossil formed when small organisms are trapped in tree sap
original material fossil
-kind of fossil involving freezing or mummification.
-the remains of the organism have not been replaced with minerals
gradualism
-the theory that the earth is constantly and slowly changing
evolution
-genetic change in a population over time
-does not happen to individuals
species
-a group of organisms that can interbreed and have fertile offspring
speciation
-the formation of a new species because of accumulated changes that make the new population different enough from the original population
-requires either geographic isolation, or behavioral or temporal isolation for it to occur
extinction
-the complete loss of a species, usually because of failure to adapt to changing conditions
adaptation
-something that helps an organism survive in its environment
-formed by the process of natural selection
natural selection
-non-random process when nature "chooses" organisms who have favorable traits (produced by random mutation) to reproduce better, producing offspring that have those same favorable traits
-requires: 1. variation of traits, and 2. that those traits can be inherited through reproduction
fitness
-the ability to survive and reproduce
-survival is only important because it allows more reproduction
-measured by how many fertile offspring an organism has
common descent
the idea that all living things are related and come from a common ancestor
descent with modification
-the idea that offspring look different from their parents/ancestors.
-many of these differences can be explained by random mutation
Galapagos finches OR tortoises
-organisms observed by Darwin
-their unique adaptations to each island, and yet similar appearance to each other, made him propose that tortoises on the islands originated from a single species from the mainland (and the same for finches)
Homologous structures
-body parts of different organisms made from the same components but often adapted for different uses
-examples: human arm, whale flipper, bat wing
-evidence of common ancestry
DNA (molecular) analysis
-comparison of nucleotide base sequences in the genes of organisms
-used, along with amino acid sequences, to determine the evolutionary relationship between two or more species
-two closely related species will be more genetically similar
-evidence of common ancestry
Embryology
-study of the earliest stages of development of organisms
-comparison of embryos in mammals and other vertebrates shows similar developmental patterns and processes
-evidence of common ancestry
Vestigial structure
-body parts in animals that have been reduced in size and function
-exist because the ancestral structures were no longer beneficial
-examples: whale hip and thigh bones, human tailbone
-evidence of common ancestry
Biogeography
-the distribution of living organisms and fossils over the earth
-can be explained by common ancestry
-evidence for evolution
camouflage
-adaptations allowing organisms to blend in with their environment to avoid predators
mimicry
-adaptations allowing "harmless" organisms to appear like "dangerous ones" to avoid predation
Gene flow
-the introduction of alleles (genetic information) from one population to another by immigration
Genetic Drift
-random evolutionary changes in a population, causing a loss of diversity
-occurs more in small populations
-2 mechanisms in the notes: the bottleneck effect and the founder effect
bottleneck effect
-a cause of genetic drift when a disaster randomly destroys a larger portion of a population
-survivors reproduce and the gene pool (genetic makeup) of the population is different and less diverse
founder effect
-a cause of genetic drift when a small number of organisms colonize an island
-the gene pool (genetic makeup) of the population is different than the originating population
mutation
-the ultimate cause of all variation
-can change the genetic makeup of a population but cannot produce useful change alone (without natural selection)
nonrandom mating
-when organisms mate preferably with those in proximity or with those only with specific traits
allopatric speciation
-kind of speciation occurring when two populations of the same species become separated by geographic barrier
-loss of gene flow between populations allows them to evolve into new species
sympatric speciation
-kind of speciation occuring when two populations of the same species evolve into different species without a geographic barrier
-although no geographic barrier present, some sort of behavioral or temporal isolation must exist
behavioral isolation
-allows speciation if the mating behaviors of two populations is different so that there is no interbreeding
temporal isolation
-allows speciation if the timing of reproduction of two species is different so that there is no interbreeding
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