the trait that often changes after time is the size of the organism. It usually will get larger after a period of time.
If there were no differences in an organisms ability to survive and reproduce what would there be to select from? Variation in populations is key to the naturally selective process and these variations that are reproductively successful are passed on to progeny which leads to the change in populations over time called evolution.
Individual organisms differ, but some of this variation is heritable. Species alive today are descended with modifications from ancestral species that lived in the distant past.
Evolution is the change in allele frequency over time in a population of organisms. Change over time and a fact. Natural selection is the nonrandom survival and reproductive success of randomly varying organisms and explains much about the fact of evolution.
Competition between organisms (Apex)
Genetic bottleneck causes very little genetic variation and can cause genetic drift.
Without variation there is nothing to select for against the background of an immediate environment and thus no evolution as alleles, not selected for, would not change over time in this population of organisms. Without variation the environment can change quickly and send your population to extinction if there were no variants that could meet this challenge.
Yes. Without variation in organisms for natural selection to choose from there would be no change in allele frequency over time in the population of organisms under discussion. This is the definition of evolution, so without change over time, no evolution.
Yes, it is. If there is variation in a populations, and a sudden catastrophic event occurs, there is more of a chance that some of the individuals in the population will survive, and the population will not die out.
By favoring one variation of organism over another variation in the same population. These favored individuals ( natural selection selects individual organisms ) leave more descendants, with these traits, who over time become more numerous in the population and the populations allele frequency changes to reflect this. In a word, evolution.
Nonrandom mating refers to individuals in a population having an equal opportunity to mate with other organisms in the population. Most organisms choose their mates based on physical and behavioral characteristics. Reproductive isolation refers to physical barriers segregating population and therefore causing change in genetic variation.
Because of population density
Evolution is change over time in a population of organisms. Formal and impressive to teacher definition is this; ' Evolution is the change in allele frequency over time in a population of organisms. '
In any population of organisms you have variation, which means, to a greater or lesser extent, that allele frequencies are varied and great in number and not all of the organisms of the population possess the same alleles. Now some of those alleles confer reproductive advantage in the immediate environment. These organisms will be selected and the allele frequency possessed by these organisms will be the change in allele frequency that will show up in the populations gene pool.
Genetic drift. This phenomenon occurs due to random chance events which can lead to certain alleles being more or less common in a population over time.
No, organisms die.Evolution is the change in allele frequency over time in a population of organisms.
They provide the variation in organisms that other recombination methods do not. A beneficial mutation, leading to a small change in same trait, that is even marginally reproductively successful to the organism that possesses it will be selected for and passed on tho progeny thus changing the organisms population over time, regardless of how small the change. This is evolution, change in populations over time.
By natural selection. These organisms have variations that allow some to survive and reproduce better than other organisms. The ones that do reproduce better leave more copies of their genes in the populations gene pool. This is the definition of evolution; evolution is the change in allele frequency over time in a population of organisms.