Answer: Java Man & Peking Man. Java man: a. Homo erectus fossils of Java were called Java man. b. Its fossils were first obtained by Dubois (1891) and these were named Pithecanthropus erectus. c. The cranial capacity was about 940cc. […]
Tag: 12th std biology
Explain embryological evidences of evolution.
Answer: Embryological Evidences of Evolution. All living organisms in their early developmental stages show presence of the following distinct features: i. Development in sexually reproducing organisms begins from a single diploid cell stage, i.e. a fertilized egg or zygote. ii. Zygote […]
Describe any two biological evidences of evolution.
Answer: Biological Evidences of Evolution. i. Palaeontological evidence of evolution. a. Fossils are defined as the dead remains of plants and animals that lived in the past in various geological layers. b. Unlike the evidences from other branches of biology, evidence […]
Write a note on “Genetic drift”.
Answer: Genetic Drift. i. Any alteration in allele frequency in the natural population by pure chance is called genetic drift. ii. For example, elimination of a particular allele from a population due to events like accidental death prior to mating of […]
Define Gene pool. Explain the terms: Gene pool and Gene frequency.
Answer: Gene Pool & Gene Frequency. Gene Pool: The sum total of genes of all individuals of interbreeding population is called gene pool. i. It refers to the sum total of genes of all individuals of interbreeding population. ii. Changes […]
Explain modern synthetic theory of evolution.
Answer: Modern Synthetic Theory of Evolution. Julian Huxley proposed term ‘modern synthesis’. This theory was based on the work of Dobzansky. The salient features are as follows. i. According to the Modern synthetic theory of evolution, population is considered as […]
Describe the concept of “Survival of the fittest”.
Answer: Survival of the fittest. Survival of the fittest or Natural selection: i. The organisms having favourable variations succeed in the struggle for existence. ii. The organisms with unfavourable variations are unfit to survive and they perish. iii. This means […]