Reproduction
Reproduction
Sexual reproduction is widespread in animals and this section explains why.
Learning Outcome: Summarize how sexual reproduction impacts variation, the problems associated with successfully reproducing, and the relationship of reproduction to fitness.
In an evolutionary sense, the “winning” alleles are the ones that become most frequent within a population over generations. Mating behaviors are critical for this reproductive success.
Fitness is surviving and reproducing, potentially passing on alleles to future generations. This video introduces the significance of sexual reproduction.
Watch this video; you can select the closed captioning “cc” option if you would like to see the text.
Sexual reproduction takes time and energy and can be lethal if it involves physical competition.
What is the genetic advantage of mating that could outweigh the disadvantages?
This pair of South American cichlids (Apistogramma sp.) exhibit sexual dimorphism, a difference in male and female phenotypes. The male and female differ in color, pattern, and behaviors. Individuals in this species pair bond and jointly raise their fry.
These “Endler” guppies are smaller than the “Fancy” guppies commonly seen in stores and closer to wild guppies in size, colors, patterns, and behaviors. Note the sexual dimorphism between the males and females.
These are direct descendants of wild guppies from Trinidad. Even though they are in captivity, it is difficult to monitor mating behaviors. From the video you can see how hard it is to track individual animals, especially the females that lack phenotypic differences humans can readily see.
Mating behaviors can be innate, learned, or a combination of the two.
Ephemeral insects like mayflies may only have a few days as adults to successfully reproduce. Mating behaviors are relatively simple and require innately programmed behaviors that are triggered by environmental cues like day length and temperature.
Some animals like these coastal birds utilize breeding grounds (like this rock) that minimize the search for potential mates and provide a protected site for nests and offspring. There is still debate on how much the use of breeding grounds is innately programmed, and how much is learned from other birds.
Good care is necessary to support animal husbandry
One of the indicators of successful animal care is whether an organism is healthy enough to reproduce. This is particularly critical in raising farm animals that produce eggs and milk, but is a general indicator of adequate diet, activity, and housing.
Pet social behaviors, including mating behaviors, can be altered by changing population number, diet, cage sizes, and by adding stress-reducing manipulatives like toys and objects to chew.
The next section explores mating behaviors, from simple to complex.
Check your knowledge – Reproduction
Review your notes. Can you describe the relationship between animal reproduction and fitness? If so, move forward to the next page.
Learning Objective:
Summarize how sexual reproduction impacts variation, the problems associated with successfully reproducing, and the relationship of reproduction to fitness.
Go back to Learned Behaviors Page
Go forward to the Mating Behaviors Page
Fitness Contents
Complete all five of these sections before taking the quiz and submitting your media piece.
This Module
9: Why does it behave like this?
This Guide
9A: Fitness
Products Information
9A: Quiz & Media
