Questions pertaining to the processes by which new species arise.

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1answer
59 views

Examples of animals with different number of chromosomes that can interbreed?

When I was first started to write this question, I wanted to know how species evolve to have a different chromosomal arrangement, such as having two pairs of chromosomes instead of one? However, I ...
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1answer
84 views

Can we say that microevolution and macroevolution is fundamentally the same thing over different time scales?

This Wikipedia article states: Macroevolution is evolution on a scale of separated gene pools. Macroevolutionary studies focus on change that occurs at or above the level of species, in contrast ...
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2answers
203 views

Definition of “Niche Complementarity”

What does "Niche Complementarity" means? On this website they define "Niche Complementarity" as: The tendency for coexisting species which occupy a similar position along one niche dimension ...
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0answers
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Speciation and Phylogeny of Lactobacillus

The lactobacillus, also called Döderlein's bacillus is a genus of facultative aerobic bacteria. There are several species such as Lactobacillus acidophillus and Lactobacillus reuteri. I have several ...
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2answers
87 views

How likely is it that Earth has millions of different species?

I know that the probability of life existing on a habitable planet is pretty slim. But, how likely is it that it hapenned millions of times in the same planet? Or was it only a few species that ...
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1answer
77 views

Cats, Dogs and Bears - how are they related?

What is the ancestral relationship between cats, dogs and bears? I presume they are more closely related to one another than other paraphyletic clades of mammal. Which came first? What did their ...
2
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1answer
51 views

Does the existence of one species imply the existence of many other?

Reading one of Sir Arthur Clarke's scifi stories, I came across a statement something to the effect of, existence of a single species automatically implies the existence of many other species. So ...
5
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1answer
142 views

Empirical evidence for species selection

Do we have any empirical evidence in favor of species (or lineage) selection? Do we know some cases that can only be explained (or seem to be only explained) by lineage selection? What are today the ...
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1answer
49 views

Systematic difference of diversity between sister taxa?

When looking broadly at the tree of life, my feeling is that, after a divergence there is almost systematically one taxon that speciates way more than the other. (There will have some approximations ...
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3answers
1k views

Species with reproduction barriers that can both reproduce with a third species

To start with, I do not have a sound knowledge in biology or any formal education in the area. I was told that one of the definition of a species is a reproductive barrier, which means that if two ...
2
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1answer
883 views

Speciation by polyploidy

Speciation can occur by polyploidy. My understanding of the process is as follows: 'polyploidy is when the number of chromosomes in an organism's cell doubles. This means that the organism has more ...
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2answers
319 views

Evolution in 37 years, is it possible?

I am confused, can evolution ( speciation ) really occur in such a short time ? In 1971, biologists moved five adult pairs of Italian wall lizards from their home island of Pod Kopiste, in the ...
3
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1answer
128 views

Were there lifeforms before LUCA?

This question got me thinking about something. LUCA is the last universal common ancestor of all current living organisms, which is a very different definition from the first-ever living organism. Is ...
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1answer
114 views

Is extreme cladism a mainstream position in the species debate?

In the philosophy of biology it has been claimed many times that a popular position regarding the question of what species are, among biologists, is cladism. For my current purposes, the defining ...