Evolution — BIOLOGY STD 12 Science — Question

→ The rate of emergence of new forms of organisms and the life cycle OR are related to life span.
→ The rate at which new forms of organisms appear and is related to the life cycle or life span.
→ Rapidly dividing microorganisms have high multiplicity, reach millions within hours.
→ A colony of bacteria growing in a given culture medium (say A) varies in terms of its ability to utilize food components.
→ If the composition of the medium is changed, only that fraction of the population (say B) that survives the changed condition will remain.
→ Over a certain period of time, a variant form of this population will outgrow the others and come into being as a new species.
→ But when this matter is applied to fish or chicken, it takes millions of years because their life span is in years.
→ It can be said that B's fitness is better than A's under the new conditions.
→ So called fitness are based on characteristics or inherited.
→ Therefore there must be a genetic basis for selection and development.
→ In other words some organisms are better adapted to survive in a changing environment.
→ Adaptability is hereditary. It has genetic basis.
→ Fitness is the end result of the ability to adapt and to be selected by nature.
→ Two key evolutionary concepts developed by Darwin are natural selection and branching.
→ Darwin stated that variations that are inherited and are well adapted to a particular habitat and resource.