According to Hugo De Vries, speciation is due to __________.
Single-step large mutation
Hugo de Vries, working on the evening primrose (Oenothera lamarckiana), put forward the mutation theory of evolution.
He held that evolution is caused by mutations, which are large, sudden and random changes, rather than by the minor variations stressed by Darwin. According to him, a single-step large mutation brings about speciation, and he called this saltation.
Accumulation of small variations is the Darwinian view: Darwinian variations are small and directional, and evolution is gradual. Intraspecific breeding only reshuffles variation within one species, and interspecific breeding (hybridisation) is not the mechanism de Vries proposed for the origin of new species.
Single-step large mutation option is correct.
Similar Questions
In a practical examination, the below given pedigree chart was given as spotter for identification.
The students identified the pedigree chart as ________
Identify the correct order of stages in Human evolution.
a) Homo habilis
b) Homo erectus
c) Australopithecus
d) Neanderthal man
e) Dryopithecus
Select the statement which is ‘NOT’ true about Big Bang Theory.
Arrange the below given steps of DNA fingerprinting in sequence by selecting the appropriate option.
a) Digestion of DNA by restriction endonucleases
b) Autoradiography
c) Blotting of DNA fragments to nitrocellulose membrane
d) Isolation of DNA
e) Separation of DNA fragments by electrophoresis
In a DNA molecule, cytosine is 28%. Calculate the percentage of adenine.
Who amongst the following scientist/s had no contribution in the development of the double-helix model for the structure of DNA?
Thalassemia and Sickle cell anaemia are due to a problem in globin molecule synthesis.
Select the correct statement.
Read the following statements.
Statement I: In a typical test cross, an organism showing a dominant phenotype is crossed with the recessive parent.
Statement II: The ratio of organisms showing dominant and recessive traits in F1 generation of a test cross indicates that the organism with unknown genotype is homozygous dominant.
Choose the correct option.
The classical example of point mutation is
The genotypes of husband and wife are IAIB and IAIO. Among the blood groups of their children, how many different genotypes and phenotypes are possible?
Important Questions from Genetics and Evolution
- Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A : Forelimbs of human and bats are homologous.
Reason R : Forelimbs of humans and bats have similar anatomical structure.
In the light of the above statements, choose the most appropriate answer from the options given below : - Given below are two statements :
Statement I : Modern *Homo sapiens* arose in Australia and moved across continents.
Statement II : *Homo sapiens* arose around 75000 to 10000 years ago.
In the light of the above statements, choose the most appropriate answer from the options given below : A population of diploid organisms is at Hardy-Weinberg equilibrium. If the frequency of allele A is 0.1, the frequency of AA is ____________ .
Adaptive radiation in placental mammals and Australian Marsupials leading to similarity between distant species is an example of ___________
- Natural selection can lead to
(a) stabilisation
(b) genetic drift
(c) directional change
(d) disruption
Choose the correct answer from the options given below :
