Natural selection causes changes in
The primary thing that natural selection causes changes in is the frequency of certain traits within a population over time. Natural selection works by favoring certain traits that provide an advantage for survival and reproduction in a particular environment. Organisms with these advantageous traits are more likely to survive and have offspring, passing on those favorable traits to the next generation. Thus, over time, the frequency of these advantageous traits increases in the population, leading to changes in the overall characteristics of organisms.
Natural selection causes changes in populations over time. It is a process that leads to the increase in frequency of certain heritable traits within a population, while decreasing the frequency of other traits. These changes occur as a result of the differential survival and reproduction of individuals with certain advantageous traits.
Here is a step-by-step explanation of how natural selection causes changes:
1. Variation: Within any population, there is variation in traits among individuals. These variations can be genetic, resulting from mutations, or due to recombination during sexual reproduction.
2. Heritability: Some of these variations are heritable, meaning that they can be passed down from parents to offspring. Genetic traits that are passed on through generations are the ones that can undergo natural selection.
3. Selective pressures: Natural selection acts on populations when there are certain selective pressures that favor individuals with specific traits. These pressures can be environmental factors, such as access to food, competition for mates, or resistance to diseases.
4. Differential survival and reproduction: Individuals with traits that are advantageous in their environment are more likely to survive and reproduce successfully. These advantageous traits increase the chances of survival, mating, and producing offspring that inherit those traits.
5. Passing on traits: As individuals with advantageous traits reproduce more, their offspring inherit these traits, leading to an increase in the frequency of those traits within the population over time.
6. Decrease in frequency of disadvantageous traits: On the other hand, individuals with traits that are less beneficial in their environment are less likely to survive and reproduce. As a result, the frequency of these disadvantageous traits decreases over successive generations.
7. Time and accumulation of changes: Over many generations, these small changes accumulate, leading to noticeable changes in the characteristics of a population. This process can lead to the formation of new species or the adaptation of existing species to their environment.
In summary, natural selection is a mechanism of evolution that causes changes in populations over time by favoring individuals with advantageous traits, leading to the increase in frequency of those traits and the decrease in frequency of disadvantageous traits within a population.