Final answer:
The process by which two parents contribute genetic material to offspring is called fertilization, which results in genetic variation due to mechanisms like genetic recombination, crossing over, and random fertilization. Other factors contributing to genetic variation are mutation and gene flow. Additionally, fertilization creates a diploid cell in an organism's life cycle.
Step-by-step explanation:
The term for the process by which two parents contribute genetic material to the offspring is fertilization. Fertilization occurs when two gametes, which are the sex cells from each parent (sperm and ovum in animals, or pollen and ovules in plants), unite to form a zygote. This zygote then develops into an offspring. The offspring inherits genetic material from both parents, which leads to genetic variation among siblings.
Specifically, variation among offspring that have the same two parents can arise from a few key processes:
- Genetic recombination: This is the exchange of genetic material between paired chromosomes during meiosis.
- Crossing over: A process that occurs during meiosis where chromosomes exchange segments, introducing new combinations of genes.
- Random fertilization: Out of the millions of possible gametes, the ones that unite are chosen by chance, further increasing the genetic variability.
Moreover, other processes such as mutation and gene flow also introduce new genetic variation into a population, essential for the process of evolution.
Regarding the evolutionary forces, while the process of mutation is random, other aspects like natural selection and sexual reproduction are not. Evolution overall is not a purely random process because selection acts on the available genetic variation in a non-random fashion, favoring traits that enhance survival and reproduction.
Lastly, fertilization leads to a diploid cell in a life cycle since it involves the fusion of two haploid gametes (each carrying one set of chromosomes) to form a diploid zygote with two sets of chromosomes.