Biology Species D In Evolutionary Biology, Parsimony

Biology

Species

Species D

In evolutionary biology, parsimony is similar to the Ockham's razor hypothesis, or that nature will use the simplest method possible to effect change over time.

Phylogenetic systematics is the manner in which biologists reconstruct the pattern of events that have led to evolution and the distribution of unique species. The statement "DNA is the genetic material for all prokaryotes and eukaryotes" implies that DNA is the locus material for evolutionary change.

Assumptions include that there is a strong possibility that some evolutionary changes occur in a regular, clock-like manner. For instance, over millions of years, mutations build up in DNA at a reliable rate, and then are expressed in regular changes.

These assumptions may be violated based on punctuated evolution and/or environmental changes (climate, population, extinctions, or gaps in the ecological system) that change the nature of the timing of mutation expression.

C. Yes, using molecular clocks to estimate divergence of species depends on other methods of dating that are relative. Additionally, MC analysis can be modified to look for chemical changes and reactions within the cellular structure.

Part 6 -- It is virtually impossible for a tetraploid plant to interbreed with diploid individuals due to the number of chromosomes within the process of autopolyploid. Diploids have two sets of chromosomes, tetraploids have four sets and are thus incompatible to produce viable offspring.

Part 7 -- Pre-zygotic barriers are also known as prezygotic isolation. They include: 1) temporal or habitat isolation (physical or habitat barriers that change the ecological nature of the species); 2) sexual isolation by behavior or conduct (mating rituals, culture, divergence of belief); 3) mechanical isolation -- change of genital characteristics, estrus, or fertility; 4) gametic isolation -- changes in the actual chemistry of the reproductive cells that does not allow for cross-breeding.

Part 8 -- Species are different kinds of organisms; subspecies are versions of the species. If a yellow warbler myrtle and yellow warbler Audubon can interbreed, they are likely the same or sub-species. Mating, behavior, habitat, diet, and anatomical characteristics can help biologists classify as a single or divergent species.

Part 9 -- Adaptive radiation is the process in which an organism may diversify quite rapidly into a multitude of new forms based on environment niches. In the Hawaiian Islands, for instance, the ocean creates a barrier, as do some of the mountains and volcanos, allowing species of silverswords to adapt rapidly based on diet, climate and habitat. The Big Island is a great example of this; dry and volcanic on one side; tropical and vegetative on the other. On a mainland environment, this adaptive radiation could occur again based on geologic or natural barriers that make it difficult for species to extend beyond their own habitat. Microhabitats can, and often do, create rapid adaptive variation.

Part 10

A. The major limitations on the morphological concept of species is that there is often a large amount of phenotypic variability within a species; that organisms that can interbreed sometimes have different physical characteristics, and that it does not consider if individuals of a species can produce viable offspring. For biological concepts, many species do not reproduce sexually, and then are hard to apply to the biological concept since it emphasizes reproduction. In other words, in the biological concept, species are based not on physical similarity, but on fertility.

B. In this scenario, likely the morphological concept because the butterfly populations are distinct. In this manner, we could look at not just reproduction, but differences in body function, biochemistry, behavior and genetic make-up.

Part 11 - A clade is a group consisting of an ancestor and its decedents. Extinction rates can exceed speciation rates in clades based on a sharp change in diversity, climate, and habitat for a specific organism. This can be artificial (man-caused) or natural (weather, earthquakes, climate change, etc.). Certainly much of the basic mass extinctions are examples of this; 1) the Cretaceous-Paleocene Extinction Event about 65 million years ago in which 75% of all species became extinct; 2) the Triassic-Jurassic event about 200 million years ago when 70-75% of species became extinct. In #1, the boundary event was severe enough so that the majority of non-avian dinosaurs became extinct and mammals and birds emerged dominant; in #2 most non-dinosaurian archosaurs and large amphibians were eliminated, resulting is less terrestrial competition for the remaining species.