Niche refers to an organism's role in a particular ecosystem. Niches include herbivores, omnivores, carnivores, predators, consumers, and producers
Mitochondria are unusual organelles. They act as the power plants of the cell, are surrounded by two membranes, and have their own genome. They also divide independently of the cell in which they reside, meaning mitochondrial replication is not coupled to cell division. Some of these features are holdovers from the ancient ancestors of mitochondria, which were likely free-living prokaryotes.
Answer:
Those organisms are fit which has the ability to survive in harsh climatic condition and transfer their traits to the next generation through the process of reproduction.
Explanation: Fit means they are strong and compete with other organisms for food, shelter and other survival items. Those organisms which are not fit could not survive in harsh environmental conditions and removed from that ecosystem.
The smaller a population, the greater the potential effect of genetic drift on gene frequencies.
Genetic drift is an evolutionary term which refers to the random changes in a population's allele frequencies. These changes happen by chance due to the random selection of alleles from the genetic pool in each generation. Genetic drift can lead to either loss of some alleles or the fixation of others (100% frequency). The effect of genetic drift is stronger in smaller populations. This is because, the larger the population, the larger the sample size and the slower the result of genetic drift.
