A major disadvantage of the evolutionary species concept is that it?
In 1978, when Wiley proposed a modification to the definition of the concept, he deduced four corollaries: (1) all organisms, past and present, belong to some evolutionary species; (2) reproductive isolation must be effective enough to permit maintenance of identity from other contemporary lineages; (3) morphological distinctiveness is not necessary; and (4) no presumed (hypothesized) single lineage may be subdivided into a series of ancestral-descendant "species." (3) seems to eliminate C as a possible answer. The concept does not need a difference in morphology (= appearance). You can have two animals that look the same, yet belong to different species. Older papers seem to show that the concept applies only to sexually reproducing species (whatever concept one uses, it appears difficult to apply to bacteria, for example); that seems to eliminate answer B. It is difficult to say why D (even if true) would be a disadvantage. Therefore, by elimination, A seems to be the best answer. The idea being that the evolutionary species concept does not consider whether one specie is surrounded by other species with which it can mate and mix its genetic materials (with viable offsprings). It considers that species are reproducing in isolation, not in an environment where cross-breeding is possible. (But, as you can see in my source, my information is old). If I was stuck with this question in a test, I would pick A. --- PS: This is a question about taxonomy (the way that species are identified and named), not about evolution itself. What makes two animals belong to different species? In order to answer this question, you have to adopt definitions and a protocole. There are more than one protocole and none of them are perfect (you will always find a case where it does not work). This question is about the possible disadvantage of the protocole named "evolutionary species concept".
What is the difference between phylogenetic and evolutionary species concept?
The phylogenetic species concept is proposed by Willi Hennig, who claims that a species is "the smallest set of organisms that share an ancestor and can be distinguished from other such sets." That means 2 populations on opposite sides of a river can be potentially classified as different "phylogenetic species" if the two populations differ by as little as a single allele. http://evolution.berkeley.edu/evosite/ev... "An evolutionary species is a single lineage of ancestor-descendant populations which maintains its identity from other such lineages and which has its own evolutionary tendencies and historical fate." http://www.mun.ca/biology/scarr/2900_Spe... The evolutionary species concept does not attempt to place a size restriction on any species, unlike the phylogenetic species concept. The esc also agrees with the biological species concept that interbreeding populations are to be considered the same species. The difficulty with the esc is that there is no way to delimit the species in the time dimension. Exactly when a species begins or and ends in time are unknown.
Biological species concept?
You basically already answered your own question. There are many ways to define species, depending on context and use. You gave the classic biological definition (except you meant fertile, not sterile). Unfortunately, this definition has obvious problems, and it no longer commonly in use by biologists. Most biologists now define a species as a group of organisms that interbreed to produce fertile offspring and self-segregate from groups of other, similar organisms. Hybridization is possible for some groups, but not common. Hybrids generally are not as fit as either parent species, although they may be fertile in some cases. For instance, to take dogs and wolves, these animals are kept separate by both behavior (dogs and wolves no longer behave entirely the same, and are as apt to be aggressive with one another as amorous) and by territory. Dogs live with humans and wolves don't. They generally have little interaction without extraordinary circumstances. Mule deer and white-tailed deer are very similar species that segregate by habitat. White tails are common in the east, mule deer west of the Mississippi. Their behaviors are also somewhat different, and so is their appearance. White tails run fast to evade predators while mule deer stott, a type of bounding. All of these work to keep the two types of deer separate, but sometimes hybrids do occur. Interestingly, these hybrid deer show a gait intermediate between that of their two parents. It is very ineffective for escape, and any hybrids produced are much more vulnerable to predation than either parent. This also works to keep the two species separate. There are entire books that have been written on the species concept and how it has evolved. I think the key concept to keep in mind is that there are exceptions to every rule and that the definition of species can be somewhat fluid.
How might one apply a phylogenetic species concept to bacteria?
This is extremely rough as I am on my phone so bear with me. The current method of determining bacterial phylogeny is based on sequence alignment of the 16s subunit of the ribosome. As the ribosome is responsible for creating proteins, it is an essential complex that is present in all known forms of life.The relatedness of bacteria is then determined by comparing specific 16s sequence regions and looking for homology. The more related two bacteria are, the more closely the sequences will resemble one another. This process of comparing sequences is repeated over and over again by adding more bacteria until a large tree can be made.
What are some limitations of the biological species concept?
1. Since it's dependent on sexual reproduction, the species concept may be hard to apply to organisms that don't reproduce sexually. 2. It's even more difficult to apply to prokaryotes which can transfer genes on plasmids to dissimilar prokaryotes via bacterial conjugation. Some prokaryotes can pick up raw DNA from the environment (transformation). 3. You try explaining the wholphin -- a "hybrid" and yet fertile.
In what way does comparative anatomy explain evolution?
You have it backwards: evolution explains comparative anatomy. Put another way, comparative anatomy provides supporting data for evolution.This page provides a good worksheet for how comparative anatomy provides supporting data for evolution: https://d3jc3ahdjad7x7.cloudfron...Here are some other resources: Evidence for EvolutionComparative Anatomy and Embryology - Advanced
What are the limitations of the biological concept of a species?
The word 'species' must have come about because of certain observations. Darwin used it in his title - "On the Origin of Species" so he must have had some concept in his mind as to what a species consists of. There is a common sense meaning - we call a cat a cat and say it is in the species 'cat', with a Latin name. The obvious reason is that every cat gives birth to a cat. This seems to be an obvious fact. But why are there different species and how do we know they are different? Because they look different to others, but are always the same within the species. It fell to Biology Professors to attempt a scientific answer and there have been many, but the most clear is "a group of animals that can interbreed successfully". But why they can interbreed? It is because a species is a set of individuals which are exact copies of their progenitors. Their genetic material - in their chromosomes - is the same. The genetic material unique to the species is found in the set of chromosomes in the ovum (egg) of that species and must always be the same. In multicellular species a second matching set of chromosomes is brought to the egg (by a sperm) which enables the ovum to make itself into all the body cells - a body - of that species.
What are pros and cons to both the biological species concept and the phylogenetic species concept?
You somewhat already replied your guy or woman question. there are a number of the thank you to stipulate species, looking on context and use. You gave the classic organic and organic definition (different than you meant fertile, not sterile). regrettably, this definition has obtrusive issues, and it now not regularly in use with the help of biologists. maximum biologists now define a species as a team of organisms that interbreed to produce fertile offspring and self-segregate from communities of different, comparable organisms. Hybridization is possible for some communities, yet not undemanding. Hybrids usually are actually not as extra healthful as the two parent species, even nonetheless they could be fertile sometimes. for occasion, to take canines and wolves, those animals are saved separate with the help of the two habit (canines and wolves now not behave completely the comparable, and are as apt to be aggressive with one yet another as amorous) and with the help of territory. canines stay with human beings and wolves do not. they frequently have little interplay without outstanding circumstances. Mule deer and white-tailed deer are very comparable species that segregate with the help of habitat. White tails are undemanding interior the east, mule deer west of the Mississippi. Their behaviors are additionally incredibly distinctive, and so is their visual allure. White tails run quickly to avert predators collectively as mule deer stott, a variety of bounding. All of those paintings to maintain the two sorts of deer separate, yet in specific circumstances hybrids do ensue. apparently, those hybrid deer instruct a gait intermediate between that for the time of their 2 mom and dad. it extremely is rather ineffective for escape, and any hybrids produced are a lot extra in possibility of predation than the two parent. This additionally works to maintain the two species separate. there are entire books that have been written on the species concept and how it has developed. i think of the main important concept to recollect is that there are exceptions to each rule and that the definition of species could be incredibly fluid.
What is co-evolution ;explain?
These creatures didn't start out requiring each other. Determining which came first is a bit of a chicken and the egg situation (I'm sure someone's done the leg work and submitted it somewhere), but it works either way. Plants used to (and in some cases still do) spread their pollen by releasing it onto the wind, hoping that some of the cloud landed on other plants of the same species. Some low lying plants, which didn't get as much wind, or were too low to get any distance when the pollen was blown, started pollinating their outsides. Animals would pass by and brush the pollen onto their bodies. If they brushed against another plant of the same species, the pollination was successful. This method is also still being used. Soon, some plants "figured out" that they could attract certain animals by secreting nectar (a product of the glucose that plants produce). This became a very successful system, and soon plants were marking the location of their nectar deposits with colorful flowers. The insect path is even simpler. Insects require sugar as a nutrient to survive. Plant glucose is an excellent source of it. However, they had to harm the plants to get at it. Some plants started producing external nectar which allowed the insects to extract this sugar without harming the plant, which allowed for the plants to be a repeated source. Insects developed long tongues and proboscises which allowed them to get the nectar more efficiently.