teaches us that what is natural is also moral.
occurs when an organism changes before having offspring.
leads to progress.
leads to change in populations over time.
Evolution is the change in gene frequency within a population over time. It cannot occur within an organism's lifespan. Although evolution can produce changes that seem progressive, such progress is relative to the current environment.
migration
genetic drift
divine intervention
natural selection
mutation
Evolution is caused by natural selection, mutation, genetic drift, and migration.
What a stud. Such symmetry must be a result of good genes!
What a stud. That tail will make a great privacy screen during mating!
No thanks. What a show-off!
What a stud. He must be very quick and clever to have avoided attacks from predators.
A peacock’s large, symmetrical tail actually signifies good genes in two ways. Symmetry displays genetic resilience to pathogens in the womb and the burdensome quality of having a large tail shows a certain finesse in the peacock’s ability to avoid predatory attack.
It’s more fun that mitosis.
It results in genetic recombination, protecting offspring against pathogens.
It leads to a monogamous social structure.
An offspring produced through sexual reproduction has more genes than one produced asexually.
While it can be fun, the principle benefit of sexual reproduction is that it results in genetic recombination, which works like an encrypted password to prevent harmful pathogens from accessing offspring.
monogamous
polyandrous (one female, multi-male)
polygynous (one male, multi-female)
promiscuous
Sexual dimorphism is most pronounced in species with polygynous mating systems. In these systems, access to females is an all-or-nothing game in which males engage in fierce competition and must constantly uphold their status. Thus, they tend to have sexually dimorphic traits, like larger size or enlarged canines.
The act is a final display of victory over the previous alpha male.
The act is a display of formidableness to attract the females.
By killing the existing offspring, he prevents his own future offspring from facing competition.
By halting the period of female nursing, females will sooner go into heat and yield the new male’s offspring.
The lone male in a polygynous group likely fought competitively for his position and will likely be replaced by an even more formidable male. Thus, the length of his tenure is unknown and he must make the most of it. Through infanticide he can sooner bring the females into estrus and pass down his genes successfully.
determining compatibility for platonic relationships.
kin recognition.
assessing general health of an individual.
attraction to genetically-distinct mates.
Body odor carries genetic information that assists us in a number of ways. Women, who generally have a stronger sense of smell, use it to determine if a partner is a good genetic match, and may choose differently across their menstrual cycles. A person’s scent also helps us avoid inbreeding as we are not attracted to individuals with scent information similar to ours.