Chapter 4 Vocabulary Flashcards
Species
is a set of individuals that can mate and pro-
duce fertile offspring. Every organism is a member of a certain species with certain distinctive traits.
Biomes
Large regions such as forests, deserts, and grasslands with distinct climates and certain species (especially vegetation) adapted to
them.
Fossils
mineralized or petrified replicas of skeletons, bones, teeth, shells, leaves, and seeds, or impressions of such items found in rocks.
Biological evolution (evolution)
the process whereby earth’s life changes over time through changes in the genetic characteristics of populations.
Theory of evolution
All species descended from earlier, ancestral species. In other words, life comes from life.
Natural selection
individuals with certain traits are more likely to survive and reproduce under a particular set of environmental conditions than are those without the traits.
Adaption (adaptive trait)
any heritable trait that improves the ability of an individual organism to survive and to reproduce at a higher rate than other individuals in a population are able to do under prevailing environmental conditions.
Differential reproduction
Enables individuals with the trait
to produce more surviving offspring than other members of the population produce.
Speciation
One species splits into two or more different species.
Geographic isolation
Occurs when different groups
of the same population of a species become physically isolated from one another for a long period of time.
Endemic species
Species that are found in only one area are and are especially vulnerable to extinction.
Background extinction
Throughout most of the earth’s long history, species have disappeared at a low rate.
Mass extinction
Is a significant rise in extinction rates above the background level.
Reproductive isolation
Mutation and change by natural selection operate independently in the gene pools of geographically isolated populations.
Extinction
A process in which an entire species ceases to exist (biological extinction) or a population of a species becomes extinct over a large region, but not globally (local extinction).
Species diversity
An important characteristic of a community and the ecosystem to which it belongs is this, or its number and variety of species it contains.
Ecological niche (niche)
Scientists describe the role that a species
plays in its ecosystem as its ecological niche, or simply niche (often pronounced “nitch”).
Generalist species
Scientists use the niches of species to classify them broadly as generalists or specialists. Generalist species have broad niches.
Specialist species
Specialist species occupy narrow
niches. They may be able to live in only one type of habitat, use just one or only a few types of food, or tolerate a narrow range of climatic and other environmental conditions.
Native species
Are those species that normally live
and thrive in a particular ecosystem.
Nonnative species
Other species that migrate into, or are deliberately or accidentally introduced into, an ecosystem are called nonnative species, also referred to as invasive, alien, and exotic species.
Indicator species
Species that provide early warnings of damage to a community or an ecosystem are called indicator species.
Keystone species
Are species whose roles have a large
effect on the types and abundance of other species in an ecosystem.
Foundation species
Another important type of species in some ecosystems is a foundation species, species that play a major role in shaping their communities by creating and enhancing their habitats in ways that benefit other species.
Biological diversity (biodiversity)
Is the variety of the earth’s species, or varying life-forms, the genes they contain, the ecosystems in which they live, and the ecosystem processes of energy flow and nutrient cycling that sustain all life.
Mutations
Random changes in the DNA molecules.
