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>
according to nature . com
"Cytoplasm is a thick solution that fills each cell and is enclosed by the cell membrane. It is mainly composed of water, salts, and proteins. ... All of the organelles in eukaryotic cells, such as the nucleus, endoplasmic reticulum, and mitochondria, are located in the cytoplasm."
i like to refer to it as slime in the cell that gives it structure.
The ecosystem requires a constant input of energy because energy cannot be stored. The enrgy always gets converted for supporting life in the ecosystem. Some amount of energy is also lost during this conversion. So if there is not a constant supply of energy, then the ecosystem will ultimately breakdown. In case of humans, the energy is received by consuming food. The energy of the food geets converted to the enrgy that helps a human being to complete his daily chores. So energy is being lost at every step. To regain this energy the humans have to eat food regularly. This way the humans need a constant supply of energy to survive. It is the same in the case of all living things in the ecosystem.
Answer: B. Genes
Explanation:
Got it right on the test.
Heat from the sun makes it through near the Antarctic (where the hole is) is melting the ice and not allowing some key species to feed. seals don't have ice to come up for air through like normal so polar bears starve. loss of land means less food for a lot of species because the hunting grounds is closing and there is no room to expand.
