Science [1 Mark Questions]

• Evolution of species by natural selection.

• Ideas of heredity and genetics

• Stanley L. Miller and Harold C. Urey

• kale, kohlrabi, red cabbage

• Genetic drift

• Eyespots → Insect-eye → Eye-like the wings → Human-eye

• Vertebrate fossil

• Micro-evolution

• Darwin's theory of evolution

• As a naturalist, Darwin had conducted a study on the role of earthworms in soil fertility.

• A change is the frequency of some genes in a population which provides diversity without any survival advantage is called genetic drift.

• The phenomenon of determining the sex of an individual of a species is called sex determination.

• When two populations of a species cannot reproduce with each other, it is called reproductive isolation and two populations can be called two independent species.

• No, because single parent is involved in it and normal two copies of genes are inherited of parent.
• [In bacteria, few algae, fungi and bryophytes have only single set of genes in their normal body cells.]

• In meiosis, germ cells undergo reduction division forming a single set of genes from the normal two copies in all other cells of body.

• The study of fossils important for to study of evolution of any species as well as the idea about the extinct species.

• From fossils, we know that exinct species ever existed.

• Fossils evidences in the field of biology are considered to be the ancient documents.

• Feathers present in head region of fossilized specimens of Dinosaurs indicate that the birds are closely related to Dinosaurs.

• A flatworm named Planaria posseses very simple eyes. That are in form of eyespots which detect light.

• The extinct animals Archaeopteryx and Dinosaurs are studied from their fossils.

Conclusion : The dinosaur could not fly and it is possible. that the evolution of feathers had nothing to do with flight. But during evolution reptiles may have given rise to birds.

• Environment selects the best variant organisms with better adaptation. New species are evolved from such highly adapted species after many generations is called natural selection.

• The gradual process by which complex and diverse life forms are created from simple form of organisms by different evolutionary forces over a long time is called evolution.

• The phenomenon of origin of a new species from the pre-existing one due to reproductive isolation of a part of its population is called Speciation.

• It is a distinguishing features of a person’s character.
• In simple term, trait is the way in which the characters of an organism are expressed.
• Example : Blond hair, blue eyes, attached earlobes, tallness, etc.

• A process of transmission of characters generation after generation is called Heredity.
• It is a process by which parental characters are transmitted to offsprings.

• The genetic footprints of Homo sapiens can be traced back to our African roots.

• The same tools for tracing evolutionary relationships – excavating, time-dating and study fossils, as well as determing DNA sequences have been used for studying human evolution.

• The dinosaur skull fossil was found in the Narmada Valley a few years ago.

• When the two species show more common characteristics, they are more closely related. Such two species show that they diverged recently. This indicates that they had a common ancestor.

• On the basis of similarities and fundamental differences among organisms, a hierarchy is developed that is used in making classification groups.

• Characteristics are the details of appearance or behaviour of an organism showing a particular form or a particular function.

• Micro-evolution means a small change in common characteristics of a group of organisms of a particular species. Microevolution is change in gene frequencies of populations. Slowly and gradually micro-evolution helps in the progressive change of population. Microevolution does not explain the process of speciation.

• No, because loss of tail cannot change the genes of the germ cells of the mice.

• The lowest part of the ear pinna is called earlobe. Amongst two variants, free earlobe is dominant and attached earlobe is recessive.

• Selection of variants by environmental factors forms the basis for evolutionary processes.

• No, because depending on the nature of variations, different individuals would have different kinds of advantages.

• Evidences from analogous organs do not suggest any common ancestory in the course of evolution.

• Homologous organs → Bird arms and bat arms,
• Analogous organs → Wing of a bird and wing of a bat.