Chapter 25 Origin of Earth Flashcards
Mutation
change in genetic info (error in DNA, radiation or chemicals, or spontaneous)
Natural selection
individuals with heritable traits that boost survival reproduce at a higher rate
Genetic Drift
chance event decreases frequency of alleles
Non-random mating
some individuals are more or less likely to mate with individuals of a particular genotype than with individuals of other genotypes
Gene flow
transfer of alleles from one population to another
Mutualism
the ecological interaction between two or more species where each species has a net benefit
Commensalism
a relationship between individuals of two species in which one species benefits from the other without either harming or benefiting the latter
Decomposer
An organism that feeds on and breaks down dead plant or animal matter, making organic nutrients available to the ecosystem
Parasite
an organism that lives on or in a host organism at the expense of its host
Radiometric dating
based on the decay of radioactive isotopes
Molecular clocks
an approach for measuring the absolute time of evolutionary change based on the observation that some genes and other regions of genomes appear to evolve at constant rates
Name the four theories of how life began on Earth
1) UV radiation/lightning provided energy in a reducing atmosphere
2) Neutral atmosphere (N and CO2) with pockets of reducing air + energy from volcanoes
3) Deep-sea hydrothermal vents, more specifically alkaline vents (high pH and warm, not hot)
4) Meteorites brought L and D isomers (amino acids) from space
Name the four steps that led to the formation of simple cells
1) The abiotic (nonliving) synthesis of small organic molecules, such as amino acids and nitrogenous bases
2) The joining of these small molecules into macromolecules, such as proteins and nucleic acids
3) The packaging of these molecules into protocells, droplets with membranes that maintained an internal chemistry different from that of their surroundings
4) The origin of self-replicating molecules that eventually made inheritance possible
State the results of Endosymbiosis
- Results in double membranes + nuclear and mitochondrial DNA
- Results in ability to produce high volumes of ATP
Endosymbiosis
A relationship between two species in which one organism lives inside the cell(s) of another organism; the theory that mitochondria and plastids originated as prokaryotic cells engulfed by a host cell.
