Compare and contrast two biomes

    One biome is the freshwater biome. Freshwater is defined as having a low salt concentration usually less than 1%. Plants and animals in freshwater regions are adjusted to the low salt content and would not be able to survive in areas of high salt concentration (i.e., ocean). These ponds and lakes range in size from just a few square meters to thousands of square kilometers. Another biome is the desert biome. Deserts cover about one fifth of the Earth's surface and occur where rainfall is less than 50 cm/year. Most deserts have a considerable amount of specialized vegetation, as well as specialized vertebrate and invertebrate animals. Soils often have abundant nutrients because they need only water to become very productive and have little or no organic matter. Disturbances are common in the form of occasional fires or cold weather, and sudden, infrequent, but intense rains that cause flooding.The difference between freshwater and desert biome is that the desert hardly has any water while the freshwater biome is covered with water.

Which level of a food pyramid is the most important?

      At the base of the food pyramid, you will see the group that contains breads, grains, cereals and pastas. These foods provide complex carbohydrates, which are an important source of energy. Fruits and vegetables are rich in nutrients. Many are excellent sources of vitamin A, vitamin C, folate or potassium. They are low in fat and sodium and high in fiber. Meat, poultry and fish supply protein, iron and zinc. Non-meat foods such as dried peas and beans also provide many of these nutrients.Products made with milk provide protein and vitamins and minerals, especially calcium.A food pyramid's tip is the smallest part, so the fats and sweets in the top of the Food Pyramid. So in conclusion i think the most important part is the dairy products because they have all the good stuff from the other levels on the pyramid.

Are we the 6th

Yes I think that we are impacting the 6th exctition. WE the humans are killing our planet by polution and using all the resources we can get our hands on we are hunting off animals, we are even  killing off ourselfs in war. Yes I think humans are playing a role in the 6th exctition. Unless a big event happens that kills off a lot of people.

directional,stablizing, and distuptive

     Directional selection favors those individuals who have extreme variations in traits within a population. Stabilizing selection favors the norm, the common, average traits in a population .Disruptive selection, like directional selection, favors the extremes traits in a population. Disruptive selection differs in that sudden changes in the environment creates a sudden forces favoring that extreme. Directional occurs when selection favors one extreme trait value over the other extreme. This typically results in a change in the mean value of the trait under selection. Distuptive occurs when selection favors the extreme trait values over the intermediate trait values. In this case the variance increases as the population is divided into two distinct groups. Disruptive selection plays an important role in speciation. Stablizing occurs when selection favors the intermediate trait value over the extreme values. Populations under this type of selection typically experience a decrease in the amount of additive genetic variation for the trait under selection.

The fossil Record

   The fossil record is incomplete because very few organisms were preserved as fossils. organisms tend to decay before becoming a fossil. Animals with hard parts are preserved more easily and geological processes may destroy fossils. Darwin believed that the fossil record showed the history of life on earth.The fossil record of all species is not complete because the circumstances for fossils to occur is very rare.

Microevolution

          Microevolution is a change in gene frequency within a population. This change is due to four different processes mutation selection , gene flow and genetic drift
population genetics is the branch of biology that provides the mathematical structure for the study of the process of microevolution. Ecological genetics concerns itself with observing microevolution in the wild. Typically, observable instances of evolution are examples of microevolution; for example, bacterial strains that have antibiotic resistance
Microevolution can be contrasted with  marcoevolution, which is the occurrence of large-scale changes in gene frequencies in a population over a geological time period  difference is largely one of approach. Microevolution is reductionist, but macroevolution is . Each approach offers different insights into the evolution process. Macroevolution can be seen as the sum of long periods of microevolution, and thus the two are qualitatively identical while being quantitatively different.

why is evolution a theory and not a law

  Different theories and laws can end up to be wrong, and must be tested by considering what evidence we should find if the theory or law were false, and then looking for such evidence. For example if the theory of evolution were false then we shouldn't expect the similarities between living things to show a nested hierarchy, where in two species share many similarities some of which are shared by more distantly related species, and some of those of which are shared by more distantly related species; etc. Since we do in fact find such nested hierarchies of similarities, and since we would not expect to find such hierarchies if everything were made from scratch to look as it does now, that is strong support to indicate the theory is correct