Evolution and Biological Adaptation

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. So, a new species is formed from existing population when it is geographically isolated and not by different size of genitalia, different mating time and seasonal variations.

Geographical isolation: The separation of two populations of the same species or breeding group by a physical barrier, such as a mountain or body of water. 

• Hugo de Vries in 1901 put forward a theory of evolution, called mutation theory. The theory states that evolution is a jerky process where new varieties and species are formed by mutations (discontinuous variations) that function as a raw material of evolution.
• Mutation theory can not explain the phenomenon of mimicry (i.e. the resemblance between mimic and model), protective coloration and relationship between position of nectaries in flowers and length of proboscis of insects that pollinate them.
  
  

In the 20th century conception of evolution being caused by a number of complex and often interacting processes. This is essentially a combination of Darwin's concept of natural selection, Mendel's basic genetics, along with the facts and theories of population genetics and molecular biology. So, this theory explains almost all factors related to organic evolution. Hence, this is the most accepted theory as compared to others.

The synthetic theory of evolution is based on gene mutation, gene recombination, natural selection, genetic drift, isolation.(Other factors-migration, hybridisation,chance)

1. Mutation, recombination, natural selection, genetic drift and isolation are involved in natural selection.
2. Mutation is an important source of variation that fulfills gene pool and remains a base to polygenic or multi-factorial inheritance.
3. The process of micro-evolution is governed by natural selection and gene flow is affected by reproductive isolation.
4. Evolution is governed by genetic drift.
5. Micro-evolutionary factors create new species.
   

The modern approach for understanding the organic evolution lays stress on subjects such as chromosomal aberrations, mutations, isolation, population. Hence, Option D is correct. 

Isolation, particularly reproductive or geographic, prevents gene flow between populations. This allows populations to diverge genetically, eventually leading to the formation of new species.

Synthetic theory is considered as Modern theory and the main contributor of this theory was G.L.Stebbins. They considered 5 factors, responsible for organic evolution. They are as follows

For understanding Evolution, we consider-

Creationism is the religious belief that the universe and life originated from specific acts of divine creation, as described in the theory of special creation.

A) Darwin's characteristic choice is the procedure by which nature remunerates those people betters adjust to their surroundings with survival and regenerative achievement. It works at the dimension of qualities, areas of DNA that encode for proteins filled in as the product of life. 

B) The instrument of regenerative detachment is a gathering of developmental components, practices and physiological procedures basic for speculation. They keep individuals from various species from delivering posterity or guarantee that any posterity is sterile. 

C) Speciation is the developmental procedure by which populaces advanced to end ups particular species. 

D) Human Conversation is the intelligent correspondence between at least two individuals.

So, the correct option is 'Isolation'.

From the biogenetic law or embryological parallelism often communicated utilizing Ernst Haeckel's expression "ontogeny restates phylogeny"is an authentic speculation that the advancement of the developing life of a creature, from preparation to incubation or bring forth (ontogeny), experiences stages taking after or speaking to progressive stages in the advancement of the creature's remote precursors (phylogeny).

So, the correct option is 'Ontogeny repeats phylogeny'.

There are three systems of classification, namely artificial, natural and phylogenetic. In natural system of classification, a large number of traits are considered. It is based on morphological, anatomical, cytological, physiological and biochemical characteristics of the organisms. The artificial system of classification is based on observable characteristics of the organisms. The phylogenetic system of classification is based on genetic and phylogenetic relationships between organisms.

Taxonomy is the branch of science that deals with principles, rules and procedure of classification of organisms based on their similarities and dissimilarities. Since identification and nomenclature are the prerequisites for classification, the first step in taxonomy is identification followed by nomenclature and then classification.