Causes of speciation
<span>Geographic isolation
In the fruit fly example, some fruit fly larvae were washed up on an island, and speciation started because populations were prevented from interbreeding by geographic isolation. Scientists think that geographic isolation is a common way for the process of speciation to begin: rivers change course, mountains rise, continents drift, organisms migrate, and what was once a continuous population is divided into two or more smaller populations.
</span>Reduction of gene flow
<span>However, speciation might also happen in a population with no specific extrinsic barrier to gene flow. Imagine a situation in which a population extends over a broad geographic range, and mating throughout the population is not random. Individuals in the far west would have zero chance of mating with individuals in the far eastern end of the range. So we have reduced gene flow, but not total isolation. This may or may not be sufficient to cause speciation. Speciation would probably also require different selective pressures at opposite ends of the range, which would alter gene frequencies in groups at different ends of the range so much that they would not be able to mate if they were reunited.</span>
The correct answer is : Non-native species is the example that affects biodiversity.
These species can be an agent of unacceptable economic, biological or social aftermath.
However, these species still provides in the regional biodiversity like biotic interactions and species richness and ecosystem services.
The part of the eye that prevent light from reflecting internally and is heavily vascularized to deliver blood to the retina: choroid.
<h3>What is choroid?</h3>
The choroid is highly vascularized to provide blood to the retina and contains dark pigmentation to stop light from reflecting inside. Anteriorly, the choroid, ciliary body, and iris are all joined.. The ciliary body muscles regulate the lens's thickness. The iris acts as a diaphragm, changing the pupil's aperture at its center. This regulates how much light is allowed to enter the retina. In strong light, the iris' muscle fibers constrict the pupil to accommodate close vision; in low light, they enlarge it to accommodate far vision. Each individual's iris is a different color.
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Because the membrane is made of lipids, typically fat-soluble (non-polar) molecules are able to pass easily. In addition, smaller, uncharged polar molecules can also pass through. Use the attached diagram to help you understand.
