Unit 1: vocabulary Flashcards
clathrates
frozen chunks of ice and methane found at the bottom of the ocean
climate
long-term, predictable atmospheric conditions present in a specific area
global climate change
altered global weather patterns, including a worldwide increase in temperature, due largely to rising levels of atmospheric carbon dioxide
greenhouse effect
warming of Earth due to carbon dioxide and other greenhouse gases in the atmosphere
greenhouse gases
atmospheric gases such as carbon dioxide and methane that absorb and emit radiation, thus trapping heat in Earth’s atmosphere
haze-effect cooling
effect of the gases and solids from a volcanic eruption on global climate
Industrial Era (Industrial Revolution)
period marked by the transition in manufacturing to machines. Concentrated in Great Britain, continental Europe, and the United States, and occurred during the period from around 1760 to1840
Milankovitch cycles
cyclic changes in the Earth’s orbit that may affect climate
phenology
study of the timing of periodic life cycle events
solar intensity
amount of solar power energy the sun emits in a given amount of time
weather
conditions of the atmosphere during a short period of time
adaptive evolution
increase in frequency of beneficial alleles and decrease in deleterious alleles due to selection
allele frequency (also, gene frequency)
rate at which a specific allele appears within a population
bottleneck effect
magnification of genetic drift as a result of natural events or catastrophes
directional selection
selection that favors phenotypes at one end of the spectrum of existing variation
diversifying selection
selection that favors two or more distinct phenotypes
evolutionary fitness (also, Darwinian fitness)
individual’s ability to survive and reproduce
founder effect
event that initiates an allele frequency change in part of the population, which is not typical of the original population
frequency-dependent selection
selection that favors phenotypes that are either common (positive frequency- dependent selection) or rare (negative frequency- dependent selection)
gene flow
flow of alleles in and out of a population due to the individual or gamete migration
gene pool
all the alleles that the individuals in the population carry
genetic drift
effect of chance on a population’s gene pool genetic structure distribution of the different possible genotypes in a population
genetic variance
diversity of alleles and genotypes in a population
good genes hypothesis
theory of sexual selection that argues individuals develop impressive ornaments to show off their efficient metabolism or ability to fight disease
handicap principle
theory of sexual selection that argues only the fittest individuals can afford costly traits
heritability
fraction of population variation that can be attributed to its genetic variance
honest signal
trait that gives a truthful impression of an individual’s fitness
macroevolution
broader scale of evolutionary changes that scientists see over paleontological time
microevolution
changes in a population’s genetic structure
modern synthesis
overarching evolutionary paradigm that took shape by the 1940s and scientists generally accept today
population genetics
study of how selective forces change the allele frequencies in a population over time
population variation
distribution of phenotypes in a population
relative fitness
individual’s ability to survive and reproduce relative to the rest of the population
selective pressure
environmental factor that causes one phenotype to be better than another
sexual dimorphism
phenotypic difference between a population’s males and females
stabilizing selection
selection that favors average phenotypes
