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2. Speciation - Wikipedia

   en.wikipedia.org/wiki/Speciation

   There are four geographic modes of speciation in nature, based on the extent to which speciating populations are isolated from one another: allopatric, peripatric, parapatric, and sympatric. Whether genetic drift is a minor or major contributor to speciation is the subject of much ongoing discussion.

3. Sympatry - Wikipedia

   en.wikipedia.org/wiki/Sympatry

   Sympatric groups frequently show a greater ability to discriminate between their own species and other closely related species than do allopatric groups. This is shown in the study of hybrid zones . It is also apparent in the differences in levels of prezygotic isolation (by factors that prevent formation of a viable zygote ) in both sympatric ...

4. Parapatric speciation - Wikipedia

   en.wikipedia.org/wiki/Parapatric_speciation

   Mathematical models, laboratory studies, and observational evidence supports the existence of parapatric speciation's occurrence in nature. The qualities of parapatry imply a partial extrinsic barrier during divergence; [2] thus leading to a difficulty in determining whether this mode of speciation actually occurred, or if an alternative mode (notably, allopatric speciation) can explain the data.

5. Biology of depression - Wikipedia

   en.wikipedia.org/wiki/Biology_of_depression

   The main limitation for the monoamine hypothesis of depression is the therapeutic lag between initiation of antidepressant treatment and perceived improvement of symptoms. One explanation for this therapeutic lag is that the initial increase in synaptic serotonin is only temporary, as firing of serotonergic neurons in the dorsal raphe adapt via ...

6. Differential diagnoses of depression - Wikipedia

   en.wikipedia.org/wiki/Differential_diagnoses_of...

   Depression, one of the most commonly diagnosed psychiatric disorders, [2] [3] is being diagnosed in increasing numbers in various segments of the population worldwide. [4] [5] Depression in the United States alone affects 17.6 million Americans each year or 1 in 6 people. Depressed patients are at increased risk of type 2 diabetes ...

7. What's the Connection Between Weight & Depression? - AOL

   www.aol.com/whats-connection-between-weight...

   Emotionally, depression can take a major toll, making you feel sad, irritable, helpless or fatigued, among other symptoms. It can also manifest physically, causing aches and pains, headaches and ...