Evolution Flashcards
The change in the genetic makeup of a population with time
Evolution
Evolution is explained by the constant propagation of new ___ in the __ of a species, some of which impart an ___ ____. All living things are descendents from a single ____ ____. Each of these organisms arose as a direct result of some genetic alteration in the species that lived before them. Most evolutionary changes occur _____ over a long period of time
variations, genes, adaptive advantage, common ancestor, slowly
discredited theory of evolution that held that new organs or changes in existing ones arose because of the needs of an organism
Lamarckian evolution
Lamarckian evolution proposed that the amount of change was throught to be based on the ___ or ____ of an organ. Any useful characteristic acquired in one generation was thought to be ____ to the next. This was called an ___ ______.
use, disuse, transmitted, acquired characteristics
In reality, only changes in the DNA of the __ ___ can be inherited. In contrast, changes acquired during an individual’s life are changes in ___ ___.
sex cells, somatic cells
In charles darwin’s theory of ____ selection, pressures in the ____ select for an organism most fit to survive and _____.
natural, environment, reproduce
The ability to survive and reproduce
fitness
Darwin said a particular species that has ___ ____, allowing it to ___ effectively with the immediate environment, will produce more ____ than individuals with less _____ genetic traits. The genes of parents that are more fit are therefore ___ ___ to more offspring and become increasingly prevalent in the ___ ___. There are ___ agents leading evolutionary change
beneficial traits, cope, offspring, favorable, passed down, gene pool, 6
When more offspring are produced than can survive, and therefore, the food, air, light and space are insufficient to support the entire population
overpopulation
Offspring naturally show differences in their characteristics compared to those their parents; later attributed to mutations
variations
When the developing population must compete for the necessities of life. Many young must die, and the number of adults in the population generally remains constant from generation to generation
competition
When some organisms in a species have variations that give them an advantage over other members of the species
natural selection
When the individuals that survive live to adulthood to reproduce and thus transmit favorable variations or adaptations to their offspring. These favored genes gradually dominate the gene pool
inheritance of the variations
When over many generations of natural selection, the favourable changes are perpetuated in the species. The accumulation of these favourable changes eventually results in such significant changes in the gene pool that we can say a new species has evolved. These physical changes in the gene pool were perpetuated or selected for by environmental conditions
evolution of new species
____ is the evolution of new species, which are groups of individuals that can _____ freely with each other but not with members of other species. ___ ___ is impossible between different species.
speciation, interbreed, gene flow
Different selective pressures act upon gene pools of each group, causing them to evolve _____. Changes in the environment, ___ / _____ to new environments, natural selection, ___ ___ and ___ are all factors that can lead to speciation
independently, migration, adaptation, genetic drift, isolation
Before speciation, small local populations called ___ often form within a species. Members of the same deme ___ one another more closely than members of other demes. They are closely related genetically since ____ between members occurs more frequently. They are also influenced by similar environmental factors and thus are subject to the same ____ ___
demes, resemble, mating, selection processes
If demes become ____ speciation may occur. When groups are isolated from each other, there is no __ ___ among them. Any difference arising from mutations or new combinations of ___ will be maintained in the ___ ___. over time, these genetic differences may become significant enough to make mating ____. If the gene pools within a species become sufficiently different so that two individuals cannot mate and produce ____ offspring, two different species have developed, and one or more new species have formed.
isolated, gene flow, genes, isolated population, impossible, fertile
Genetic and eventually ____ isolation often results from the ___ ____ of a population
reproductive, geographic isolation
The evolutionary relationships among species alive today
phylogeny
When two species from different ancestors develop similar traits due to exposure to similar environments
covergent evolution
when two species from a more recent ancestor face similar environments and thus develop similar adaptations
parallel evolution