In that way, like all forms of selection, the cause of stabilizing selection is the increased fitness and reproductive success that the median individuals have. The extreme versions or traits have a disadvantage, in one way or another. This disadvantage, in evolutionary terms, is decreased reproduction.

Classic examples of traits that resulted from stabilizing selection include human birth weight, number of offspring, camouflage coat color, and cactus spine density.

stabilizing selection: a type of natural selection in which genetic diversity decreases as the population stabilizes on a particular trait value.

What do stabilizing selection and disruptive selection have in common? They both decrease genetic variation. Under which condition would a mutation have the most impact on allele frequency? A flood kills most of the population of ants that live near a river.

Disruptive Selection Examples: Color

• Peppered moths: One of the most studied examples of disruptive selection is the case of ​London’s peppered moths.
• Oysters: Light- and dark-colored oysters could also have a camouflage advantage as opposed to their medium-colored relatives.

The 3 Types of Natural Selection

• Stabilizing Selection.
• Directional Selection.
• Disruptive Selection.

stabilizing selection

Natural selection is the process through which populations of living organisms adapt and change. Through this process of natural selection, favorable traits are transmitted through generations. Natural selection can lead to speciation, where one species gives rise to a new and distinctly different species.

Intrasexual selection, on the other hand, occurs between members of the same sex. For example, male sea lions compete for dominance over rookeries of females. Here, intrasexual selection acts on the physiology of the sea lion, to make it large enough to compete with other males for a group of females.

Traits assessed as moderately desirable or important are, for example, courage, elegance, attractiveness, thinness, talent for sports, strength, thriftiness, dominance. The least desirable, or the most undesirable are traits such as conceitedness, selfishness, insecurity, aggressiveness, fearfulness, introversion.

Intrasexual selection tends to lead to weaponry, armor, fighting ability, and threat displays. Examples include large body size in iguanas, infanticide in lions, antlers in deer, and so on.

According to a team of UCLA biologists, males of different species often fight for female attention to gain “priority access” to them for mating purposes. In fact, the researchers came up with a model that predicts as competition for mates increases, male aggression increases.

intrasexual in British English (ˌɪntrəˈsɛksjʊəl) adjective. occurring within a sex, or between members of the same sex. Collins English Dictionary.

Intrasexual competition can be defined as the struggle between members of one sex to increase their access to members of the other sex as sexual partners. In our species, height is a sexually dimorphic trait probably involved in both intrasexual and intersexual selective processes.

Why do females care more than males? Females tend to provide more parental care than males. The model shows that, contrary to a number of recent analyses, lower probability of parentage for males does tend to make males less likely than females to provide care.

Males tend to compete with one another to gain the female’s attention. An extreme example of intersexual selection can be found in species where males form leks where multiple males gather to display to females.

Assortative mating. Human mating is inherently non-random.

The more elaborate forms of courtship frequently help strengthen a pair bond that may last through the raising of the young or even longer. Another important function of courtship is its use as an isolating mechanism, a method of keeping different species from interbreeding. (See also display behaviour.)

Females tend to be the choosier sex when it comes to selecting a mate, partly because males can produce millions of sperm, whereas females’ eggs are few and far between. Thus, females may be more selective because they have more invested in each gamete and in the resulting offspring.

New evidence that humans choose their partners through assortative mating. This phenomenon, called assortative mating, is a mating pattern and a form of sexual selection in which individuals with similar traits mate with one another more frequently than would be expected under a random mating pattern.

Females of most vertebrate species exhibit recurring periods of heightened sexual activity in which they are sexually attractive, proceptive and receptive to males. In mammalian females (except Old World monkeys, apes and humans), this periodic sex appeal is referred to as ‘heat’ or ‘estrus’.

Throughout recent history and around the world, most heterosexual human bleeping takes place in the so-called “missionary position”—a man-on-top formation that researchers Peter Gray and Justin Garcia, in their book Evolution and Human Sexual Behavior, discuss as having little to do with missionaries, because, for …

Spay (or neuter) first Spay or neuter your dog as soon as possible. The longer a dog goes before neutering, the more difficult it will be to train them not to mark in the house. Spaying or neutering your dog should reduce urine-marking and may stop it altogether.

The first thing to do when a previously house trained dog begins urinating or defecating inside is to rule out any medical problems. Urinary tract infections, cystitis (bladder inflammation), bladder stones, kidney disease, or arthritis or age-related incontinence could all be causes of house soiling in dogs.

Your pet may be urine-marking if: The amount of urine is small and is found primarily on vertical surfaces. Dogs and cats do sometimes mark on horizontal surfaces. Leg-lifting and spraying are common versions of urine-marking, but even if your pet doesn’t assume these postures, he may still be urine-marking.

When You Should Neuter Your Dog This is an important question to consider because issues can form if this procedure is done too soon or too late. The recommended age to neuter a male dog is between six and nine months. However, some pet owners have this procedure done at four months.

Typically, when a dog is marking it is a small amount of urine in several places. These places may be random, or they could be in a favorite spot. Dogs can mark for many reasons; the two most common are to show ownership on what they consider their territory and anxiety.