2. Clearly and formally outline the logic of the process of natural selection. F
ID: 194071 • Letter: 2
Question
2. Clearly and formally outline the logic of the process of natural selection. Frame your answer in general terms applicable to any species (rather than in the style of a "parable" as in "Fast rabbits evolved because..."). Think about the logic of the proces as expressed by Darwin in On the Origin of Species and be sure to give example of ecological factors that are important in the "struggle for existence".
3. Name and describe the evolutionary process that results in anlogies, providing real examples of analogous structures to support your answer.
Explanation / Answer
Ques-1:
The evolution is defined as the significant genetic alteration in a population that includes a change in allelic frequencies. The evolution is not going to occur without a change in fitness because fitness is considered as the relative capability of a species to get genetic representation in the next generation. The given statement, "it is the population that evolves based on "the process of natural selection", not the individual," depicts that a species that has no potential to evolve itself because the theory of evolutions is solely relied upon natural selection of traits by species in a population. Therefore, adaptations acquired by the populations as the fundamental units of evolutionary change.
According to Darwin, the reason why we have not seen any transitional or intermediate forms of species along the descendants of the common ancestor are mainly due to “natural selection”. Gradualism along with cladogenic speciation occurred by genetic variation to produce new forms of species & exterminate their parent-forms.
For instance, the natural selection and evolution of new traits have developed since in many ancient extinct species. There are both convergent evolution and divergent evolution of species according to natural selection. This kind of evolution happened among species with new traits for the "struggle for existence".
Fossil species are different and they are transitional fossils as they often resemble and exhibit both the groups of organisms. They often differ in the DNA sequences when performing DNA sequencing even though they look similar morphologically thereby paleontologists often classify them as per their interspecific and intraspecific genetic variations (pan genes, core genes) variations. Fossils are formed due to catastrophism and gradualism, their classification is based on their body size, and body weight for example dinosaurs is the common ancestors of both birds and reptiles. Thereby different paleontologists show different family trees for the same fossils.
Sheppy fossil fish species have these five traits appear in their morphology in the following order, from top layer to bottom layer spots, stripes, horns, pelvic spines and head & head crest is the soft tissue that was observed among these fish species. These features were acquired due to the natural selection. This is the small, rounded head crests in low supraoccipital crest found in a majority of fossil fish species such as Pteranodon & laytonia
Bony fishes possess much diversified structural adaptations to survive and they possess a vital reproductive capability to sustain their progeny compared to a majority of mammals. These adaptive new traits are acquired through natural selection to defend predators finally for the "struggle for existence".. Bony fishes also possess defending features to escape from predators. These bony fishes possess upper jawbone and it is movable thereby it is also called premaxillary bone (ex. Teleost).
Paired fins based locomotion- Structural adaptations of the bony fish include as their skeleton is made of bone and their well-developed respiratory organs such as gills. They possess extraordinary swimming capability and ability to float.
Pectoral fins are the adaptations for maneuvering, locomotion and for crawling. Paired with cartilaginous fishes enable locomotion whereas dorsal and caudal fins enable propulsion for locomotion and steering.
In Darwin's theory, the microevolutionary changes observed in the phenotypic features of the “finches”, beaks, tortoises and coral reefs that are observable during a scientist’s lifetime provide support for Darwin’s view that all life is connected in a branching pattern of phylogenetic tree. According to Darwin, the natural selection including genetic variations is leading to “branching pattern” in the origin of species. He concluded in his lifetime microevolutionary observation base on gradualism of species evolution with “branching interrelationships” among all living beings by meticulous “metaphor of branching pattern” as described below.
Darwin’s theory of gradualism and evolution:
Darwin uses Gradualism and he proposed that the gradual changes associated with variations of a species in a population through evolution to get adapted to the present ecosystem with no transitional forms. Human evolution based on the gradualism and their adaptations are extremely complex. Initially, in the gradualism, natural selection operates to obtain specific traits according to biome, ecosystem because of large-scale events followed by formation of rivers, water availability, and habitat formation.
Humans did not evolve from primates until just 7 million years ago; while life appeared on earth 3.5 billion years ago. Humans are well adapted to the environment and developed their adaptation features as per interspecific and intraspecific genetic variations. If the evolution timeline compressed to a calendar year, the first organism would appear around March and Humans would not appear until December 31.
Darwin has developed a meticulous scientific theory about the exact biological evolution of a species and he explained the evolution of modern species over a long period from a common ancestor based on morphological convergent & divergent features as explained below.
Descent with modification from a common ancestor means that species living at any given time such as present and pre-existing species are derived from a common ancestor and their characteristic traits reflect that ancestry as well as changes over time. New species are descended from pre-existing species finally they are able to change their traits over time as an evolutionary adaption through environmental variations.
The vestigial structures are referred rudimentary organs (human hair on chest, appendix) and they have the function in their prior evolutionary ancestors. These vestigial structures are going to support descent with modification theory because these organs have similar structural & morphological features similar to earlier ancestors (mammals) relative to separate creation. Therefore, this theory does not support ancestral features of vestigial organs different from that of homology in general.
The theory of descent is describing that the identical organisms with somewhat, identical features have evolved from one common prehistoric ancestor organism. This common ancestor includes the prospect of the unit of life and finally individual species have evolved and acclimatized by producing individual adaptations. The species have started to differentiate according to their surrounding environment for the survival and followed by selection and evolution. This is followed by the creation of diversity as species developed structural modifications to their original ancestor.
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