Lesson 3 Essay Questions

The two different types of selection differ because instead of the subject only going in one direction it will split off and go two different ways. This would be disruptive selection where there is more than one option to select or two distinct groups. For example, if some flowers and their colors. The main colors may be red, pink and white primarily, say that the more dominate color being a pink flower. What happens if we remove the pink flower from the equation? It would cause the flowers to shift toward the dominant color which in this case you might think is the red. However, in this case it is not because between red and white is the least drastic and according to phenotypes would be the color that would be dominate if pink was eliminated as an option in a directional selection there is only one trait and it is always that dominant trait that dictates body of the population. Directional selection is more based of natural selection and survival. Examples would be things such as a giraffe having a long neck to reach high foliage than other animals for survival or a bunny being a color more specific to blending into its surroundings.

There are four main groups of reptiles, known as Crocodilians, Squamates, Tuataras, and Turtles. Crocodilians consists of large reptiles which includes alligators, crocodiles, gharials, and caimans. Squamates are lizards, snakes, and worm-lizards. A worm-lizard is a subterranean burrowing reptile that resembles an earthworm, a legless lizard. Tuataras are a group of reptiles that are lizard-like in appearance but are different from squamates because their skull isn’t jointed. Turtles are the most ancient reptiles alive today. They have changed very little since they first showed up 220 million years ago. The first turtle appeared 220 million years ago.(Laura Klappenbach)

1. Compare and contrast directional selection and disruptive selection and provide an example of each.

Directional selection and disruptive selection differ because instead of the subject only going in one direction it will split off and go two different ways for example if some flowers and their colors. The main colors may be red, pink and white primarily, and the more dominate color being a pink flower. But if we remove the pink flower completely from the equation then the flowers will shift toward the dominant white color over the red. In a directional selection there is only one trait and it is always that dominant trait that dictates body of the population. The best example to show this is that in the

Directional selection and disruptive selection have quite a bit in common; however, they also have some contraries. Their biggest likeness is that they are both subcategories of natural selection. Natural selection is the process that results in adaptation of a population to the biotic and abiotic atmospheres. Directional selection takes place when an exaggerated phenotype is favored and the distribution curve alters in that direction. Such a shift can happen when a population is adjusting to a changing environment. Disruptive selection occurs when two or more extreme phenotypes are favored over any other ordinary phenotype. These two selections differ in that directional requires only one extreme phenotype whereas disruptive requires at least two. A prime example of a directional selection, is resistance to antibiotic treatment as well as insecticides. The extensive application of antibiotics and pesticides eventually develops populations of bacteria and insects that have grown resistant to the chemicals. When an antibiotic is employed, some bacteria may survive because they are genetically defiant to the treatment. These particular bacteria are likely to provide such genes for the next generation. As an outcome, the number of bacterial defiance continues to increase. Disruptive selection favors polymorphism, which is the happenings of different forms in a population of the exact same species. With thatstatement made, a classic example of disruptive selection would be that

Although sexual selection may seem like natural selection, they both happen to have different features that separate them from one another. Sexual selection involves dominance and competition between organisms. Furthermore, it deals with the attractiveness some traits hold when drawing attention to other mates. A common example is that of the peacock and its vibrant feathers. The peahens are attracted to flashy feathers that the peacock flaunts, and they will eventually choose the mate that displays itself as the most extravagant. Ultimately, they will procreate and the peacock will pass on the trait involving his feathers since he was chosen as a mate.

Directional selection is one of the types of natural selection. In directional selection, one extreme of a trait in a population experiences pressure against it. This causes a shift in the population’s genetic variance to a trait with less pressure against it. This then results in the population gradually shifting from the pressured extreme trait to the unpressured extreme trait on the other side of the spectrum. Giraffe necks are a familiar example. There was environmental pressure against the giraffes with short necks, because the individuals couldn’t reach as far to feed. Therefore, the variance of neck length shifted towards long necks from short necks. Another example is the evolution of the peppered moth in 18th to 19th century England.

The definition of disruptive selection is when the extreme phenotypes are being favoured and not the intermediate phenotypes. To simplify this, if there are two things that are very different, and one thing which is the average between the two, the two different things would be more common and the average one would be less common. An example of this is if their are mice living at a beach where there is sand, and patches of tall grass. The light mice would be better adapted to camouflage in the sand, and the dark mice would be better adapted to camouflage in the patches of tall grass, whereas the medium coloured mice wouldn't blend in with either, making them easier to be seen by predators, and causing them to die out. This can lead to two

In stabilizing selection, the individuals with intermediate phenotypes have a high chance of survival and reproductive success. Moreover, the average phenotype does not change, so not much evolutionary change will occur. On the other hand, in disruptive selection, individuals with extreme phenotypes at either end of the distribution are the ones with higher fitness, which means that the magnitude of phenotype variation will increase to the next generation.

With natural selection depending on the environment conditions, the phenotype confers can advantage or disadvantage the the indicidual with the phenotype relative to the other phenotypes in the popultion. If it is an advantage, then the individual will most likely have more offsprings that the individuals with the other phenotypes, and this will mean the the allele behind the phenotype will have greater representation in the next generation.

Predation is an interspecific interaction in which one species (the predator) captures, kills, and eats another (prey). Predation removes a prey individual from the population immediately. Different types of predators have different functional responses, meaning they differ in how changes in prey density affect the rate at which they kill prey. The set of alleles that is carried by an individual’s chromosomes is known as genotype. An individual’s observable traits is known as phenotype. Natural selection is a simple mechanism that causes populations of living things to change over time. In fact, it is so simple that it can be broken down into five basic steps: Variation, Inheritance, Selection, Time and Adaptation. Natural selection occurs

1) Natural selection is when the species survival and their reproduction determine the genetic traits compared to artificial selection that is when humans can choose their traits that will show up in their future generations. Although humans intensify and inhibit organism’s genetic traits through select ancestry, nature concerns itself with characteristics that concede improvements to a species' ability to mate and survive. when Humans select organisms to breed for selective traits, some times they select members to improve their traits. But sometimes this inbreeding can cause an expression of hazardous genes.

Directional selection happens when an exceptional phenotype is chosen, one which is favored more by the environment.

1) Directional selection and disruptive selection both change up the allelic frequencies of a population. In directional selection one trait is selected over and over again, such that over time biggest part of the population all has that one trait. For example, over time all giraffes inherited tall necks, as tall necks helps the giraffes get to their food a lot easier. Disruptive selection is different from directional selection because instead of a population moving towards one trait, the population leans towards the extremes. For example if some plants need very little light and some need a whole lot of light, but cannot use an equal amount of light, then the plants may either select to be closer to the ground to avoid light or harder

Mammals do not give birth to their youngs in an egg form on a surface area. Mammals also do not have scaly and dry skin like reptiles. Mammals such as dogs are also different than reptiles such as bearded dragons because they are warm blooded so they can stay in the cold and they also have hair and fur so they can lose that anytime when they get hot. Many mammals just shiver in the cold such as dogs.