Answer:
The atoms of a chemical element can exist in different types. These are called isotopes. They have the same number of protons (and electrons), but different numbers of neutrons.
Explanation:
Answer:
Allopatric speciation
Explanation:
Allopatric speciation refers to the geographic separation of a continuous genetic background, originating two or more new geographically isolated groups. These divergences of the original population might be related to migration in different directions, extinction of geographically intermediate populations, or geological events. During these events of speciation, emerging new barriers impede genetic flow between groups, as the two new populations that are separated can not get together and mate anymore. These barriers might be geographical or ecological.
Different stages are involved in the allopatric speciation process:
• The emergence of the barrier.
• Interruption in the genetic flow
• Slow and gradual differentiation due to the occurrence of mutations in each population and their accumulation in time.
• Genetic divergence by natural selection and reproductive isolation, impeding the two groups to mate even if the barrier disappears.
• Prezigotic isolation mechanisms favored by selection a secondary contact between the new species occurs.
The Panama isthmus is an example of allopatric speciation caused by an extrinsic geological barrier that interrupted the genetic flow between species driving to genetic changes and reproductive isolation.
Two different groups that evolved in allopatry might meet again in secondary contact if the barrier that separated them, disappears. In the Panama isthmus example, the groups that did mate, could not produce any fertile progeny because of postzygotic reproductive isolation. And the groups that did not mate, were not attracted to each other because of prezygotic reproductive isolation.
<h2><u>Science</u></h2>
Science is the study of the natural world or physical universe.It is the knowledge of anything that can be verified by experiments.Science is organised into different fields of study. These fields are physics, chemistry, biology, geography, Earth science, geology, resource science, mathematics, nutrition, astronomy, biotechnology, engineering, computer and information technology.
<h2>
<u>Additional Information</u></h2>
<h2><u>Scientists</u></h2>
Scientists are people who study science.They use observation, experimentation and theory to collect facts and learn about a subject.They perform experiments and record their results which form the basis of science and the scientific knowledge around us.Scientists gain knowledge in the different fields of science by using specific ways and methods.
<h2><u>Laboratory</u></h2>
A laboratory or lab is a building or a part of building fitted with scientific equipment.
Scientists do experiments in labs.
Labs in schools and colleges are the classrooms where practical learning and demonstrations take place
