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>
Answer:
It is both a barrier keeping unwanted things out, and a gate for nutrients to be brought in.
Enzymes are proteins that control the speed of chemical reactions in your body. Without enzymes, these reactions would take place too slowly to keep you alive. Some enzymes, like the ones in your gut, break down large molecules into smaller ones.
Thorndike's law of effect is described below.
Explanation:
- Operant Conditioning. A form of associative learning in which the consequences of a behavior change the probability of the behavior's occurance. According to Thorndike's Law of Effect. Behaviors followed by bad results are less likely to occur and behaviors followed by good results are more likely to occur again.
- The law of effect is a psychology principle advanced by Edward Thorndike in 1898 on the matter of behavioral conditioning (not then formulated as such) which states that "responses that produce a satisfying effect in a particular situation become more likely to occur again in that situation, and responses that produce
- Thorndike's Law of Effect states that a response followed by a pleasant consequence is more likely to be repeated, whereas a response followed by an unpleasant consequence is more likely to be diminished. ... This special stimulus has the effect of increasing the behavior occurring just before the reinforcer.
- Law of effect. Law of Effect. The law of effect states that if a response in the presence of a stimulus is followed by a satisfying event, the association between the stimulus and the response is strengthened.
Answer:
<u>Nervous System</u> could be studied as a direct result of having defective nuclei and may shed light on the cause of Parkinson .
Explanation:
<u>PASRKINSON DISEASE -:</u> Parkinson's disease is a progressive nervous system condition. Several regions of the brain are affected by the condition, especially an area called substantia nigra that regulates balance and movement.
A trembling or shaking (tremor) of the limb is often the first sign of Parkinson's disease, particularly when the body is at rest. Typically, on one side of the body, the tremor starts, usually in one hand. The head, legs , feet, and face can also be affected by tremors. Other hallmark symptoms of Parkinson's disease are rigidity or rigidity of the limbs and body, slow movement (bradykinesia) or inability to move (akinesia), and impaired balance and coordination (postural instability).
Emotions and thinking ability (cognition) can also affect Parkinson's disease. Psychiatric disorders such as depression and visual hallucinations are created by some affected persons. There is also an increased risk of developing dementia in people with Parkinson's disease, which is a loss in intellectual functions, including judgment and memory.
Hence , the answer is <u>the nervous system and other regions of brain</u> where the disease has a direct result of having a defective nuclei and may shed light on the cause of Parkinson .
