Chapter 3 Flashcards
what is a species
particular type of organism
what is a population
group of individuals that live in a specific region at a particular time
what is evolution
changes in population overtime (generation to generation)
what is natural selection
when inherited characteristics that enhance survival are passed down more often than characteristics that do not
who is Charles Darwin and Alfred Wallace
explained that natural selection explains the variety of life on Earth
what is adaptation
when traits that lead to better reproductive success are passed to other generations
what are mutations
accidental changes in DNA
what is convergent evolution
when closely related species that live in very different environments diverge in traits and vice versa
what is biodiversity
lifes complexity
what is artificial selection
when humans select their own direction of selections
what is speciation
process in which new species are generated
what is a phylogenetic tree
type of tree like graph that represents divergence history
what is a fossil
imprint in stoen of a dead organisms
what is the fossil record
the cumulative body of fossils worldwide
what is extinction
the disappearance of a species on earth
what does it mean when a species is endemic
the species does not occur anywhere else on earth besides its own habitat
what is background extinction rate
rate at which a species gradually goes extinct
what is a mass extinction event
event that wipes out massive numbers of a species all at once
what is a community
assemblage of populations of interacting species
what is the biosphere
total amount of living things on Earth
what are ecologists
scientists that study relationships in the biosphere
what is population ecology
examines dynamics of population change
what is community ecology
focuses on patterns of species diversity
what is an ecosystem
communities and non living things in which members interact
what is ecosystem ecology
addresses flow of energy and nutrients
what is landscape ecology
studies how populations are distributed throughout regions
what is a niche
organisms functional role in a community
what is a specialist
species with very specific requirements
what is a generalist
species with broad tolerance
what is a habitat
environment where an organisms lives
what is habitat selection
when a mobile organism choose a habitat to live in
what is population size
number of organisms present at a time
what is population density
number of individuals per unit area
what is population distribution
spatial arrangement of organisms in an area
what is a sex ratio
the proportion of males to females
what is age structure
relative number of individuals of different ages in a poplulation
what is the formula for natural increase
birth rate - death rate
what is the formula for population growth rate
(birthrate - deathrate) + (immigration rate - emigration)
what is exponential growth
when a population grows at a fixed percentage every year
what are limiting factors
factors that limit growth
what is carrying capacity
maximum population size
what is logistic growth
when a population growing at an exponential rate slows and is brought to a standstill
what is a density independent limiting factor
influence is independent of population density
what is a density dependent limiting factor
limiting factors that depend on population density
what is the life history theory
explains how natural selection influences patterns in reproduction, survival, and life span
what is ecotourisms
when a place’s natural areas attract tourists to it
