because none of them have the exact same deoxyribosenucleic acid (DNA) sequence
Take dogs as an example, color, size, temperment, inbred inherant qualities ( ie.. bird dogs, watch dogs, blood hounds) Birds are a species, while most fly, some don't
Because of different living conditions, including climate, and even adapting to changes in their environment. This can include deforestation.
The Giant Panda has 42 chromosomes.
The main difference between the typological species concept and the morphological species concept is that the typological species concept classifies organisms that share characteristics that set them apart from others, whereas the morphological species concept classifies them as the same species if they appear identical.
exotification
There is a slang phrase that says fat as a tonky pig. However, this type of pig does not appear to be a true species of pig.
They are called "ear tufts" It isn't really known why some Owl species have ear tufts. The two popular theories of why some Owls have ear tufts are: That the tufts might help provide a given owl with a distinctive silhouette, thereby allowing other owls to help recognise members of their own species by sight. That some Owl species erect their ear tufts when alarmed by approaching danger (while at the same time adopting a vertically elongate body shape different from their more rotund resting pose), it's been suggested that ear tufts help break up the owl's outline and make it appear more like a broken branch.
They can be formed by evolution: A species can't survive in it's environment so it evolves into a more adapted species Two different species can mate: A new species can appear from the offspring of two different species.
In monomorphic species, male and female appear quite similar. In dimorphic species, the males appear quite different from the females. (Life, the science of biology, 7th edition, chapter 23)
they appear because they are extinct
I think it's environmental and genetic.
The "Ten Statements" or "Ten Commandments" appear twice in the first five books of the Bible, with somewhat different texts: Exodus ch.20 and Deuteronomy ch.6.
There are several species of penguins. A different number of chromosomes can appear in each species. Studied species so far show penguins to have between 30 and 80. Emperor and rockhopper penguins both have 38 chromosomes.
No. Generally, one species gives rise to two new species by geographic and reproductive isolation. Separate species mating at best gives nonviable hybrids.
Members of Congress collectively set their own salaries. Of course, if they appear to be overly greedy, there is always the possibility that voters will want to elect different people to Congress.
There are so many species of fish and they all differ. There are some in which there appear to be no differences and others that are so different they look like different species. If you define the species then I may be able to tell you how to sex them.
The early bacterias. Hominids
You can't, you have to send a message to the members in the group.
Not to appear somewhat insulting here...But the answer's in the question, weighing things.