Alpha centuri is 4 light years from the earth. How long would it take for the light from Alpha centuri to reach earth?
1 answer:
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Complete question:
Scientists have proposed more than two dozen ways to define species. One commonly used definition, called the biological species concept, holds that populations belong to the same species if they can contribute genes to a common gene pool. Reproductive barriers block gene flow between different species. Gene flow between populations tends to hold the gene pool of a species together.
Part A - Comparing species definitions
Three of the most prominent definitions of species are the biological species concept, the phylogenetic species concept, and the morphological species (morphospecies) concept.
Drag each characteristic to the appropriate bin based on the species concept(s) to which it applies → <em>You will find this in the attached files</em>
Answer:
- Not applicable for extinct species → Biological
- Based on evolutionary history → Phylogenetic
- Relies on similarities in structure → Morphological
- Accommodates asexual reproduction / Species acceptance criteria can be subjective → Morphological and Phylogenetic
- Used by scientists in classification → Morphological, Phylogenetic, and Biological
Explanation:
The biological concept states that species are population groups that -in a real or potential way- can mate and reproduce, but are reproductively isolated from other groups.
Individuals belonging to a species cannot reproduce with members of other species.
This biological concept has limitations. Its application might present difficulties in concern with asexual reproduction species, such as bacteria, rotifer, cnidarians, plants, and etcetera.
Besides, this concept cannot be applied to the past because it is difficult to deduce reproductive capability between extinct species.
Finally, this concept is not adequate concerning hybridization zones, something to be expected considering evolutionary processes. This is the reason why it has been less accepted by botanists, as some plant species hybridize with other species.
The phylogenetic species concept defines species on a determined time and through time, and these are the horizontal and vertical species concepts, respectively. The species group is considered to be the less inclusive monophyletic group.
According to the phylogenetic concept, a species is a monophyletic group whose organisms share synapomorphies.
The establishment of species relies on molecular markers.
The morphological species concept defines species according to the shared morphological characteristics shared by all the members of the species. It is a descriptive method to separate species.
When a group differs considerably at a morphological level from another group, it is defined as a different species.
Some limitations might emerge from this species concept. It does not consider variability among individuals,
- Individuals of the same species might be polymorphic, exhibiting morphological differences between organisms. These individuals would be considered to be different species following the morphological concept.
- Some different species might be morphologically similar, despite being different. These species might be considered as one following the morphological concept.
