Evolution Flashcards
The universe is very old – almost……..billion years old
20
Earth was supposed to have been formed about……. billion years back.
4.5
There was no atmosphere on early earth. (4) compounds in released from molten mass covered the surface.
Water vapour
Methane
Carbon dioxide
Ammonia
Life appeared……… million years after the formation of earth, i.e., almost four billion years back.
500
Statemet 1: Early Greek thinkers thought units of life called spores were transferred to different planets including earth.
Statement 2: ‘Panspermia’ is still a favourite idea for some astronomers
Both are correct
For a long time it was also believed that life came out of decaying and rotting matter like straw, mud, etc. This was the theory of……….
spontaneous generation.
…………. of Russia and…………. of England proposed that the first form of life could have come from pre-existing non-living organic molecules (e.g. RNA, protein, etc.) and that formation of life was preceded by chemical evolution, i.e., formation of diverse organic molecules from inorganic constituents.
Oparin
Haldane
Early conditions on earth were
High temperature
Volcanic storms
Reducing atmosphere containing CH4, NH3, etc
In…………. S.L. Miller, an American scientist created similar conditions in a laboratory scale
1953
Statement 1: He created electric discharge in a closed flask containing CH4, H2, NH3 and water vapour at 8000C.
Statement 2: He observed formation of nucleic acids
1 is correct and 2 is incorrect
He observed formation of amino acids
The first non-cellular forms of life could have originated…….billion years back
3
The first cellular form of life did not possibly originate till about………. million years ago
2000 million
Theory of special creation has three connotations:
One, that all living organisms (species or types) that we see today were created as such.
Two, that the diversity was always the same since creation and will be the same in future also.
Three, that earth is about 4000 years old.
………….. concluded that existing living forms share similarities to varying degrees not only among themselves but also with life forms that existed millions of years ago.
Charles Darwin
The fitness, according to Darwin, refers ultimately and only to………..
reproductive fitness.
Alfred Wallace, a naturalist who worked in……… had also come to similar conclusions around the same time
Malay Archipelago
The geological history of earth closely correlates with the biological history of earth.
True
State some paleontological evidences from NCERT
(5)
A study of fossils in different sedimentary layers indicates
Geological period in which they existed.
Life-forms varied over time
Certain life forms are restricted to certain geological time-spans.
New forms of life have arisen at different times in the history of earth
Embryological support for evolution was also proposed by……… based upon the observation of certain features during embryonic stage common to all………. that are absent in adult.
Ernst Heckel
vertebrates
Embryo of all vertebrates including human develop a row of vestigial gill slit just……… the head but it is a functional organ only in fish and not found in any other adult vertebrates
behind
Statement 1: Embryological support for evolution was also proposed by Ernst Heckel was disapproved on careful study performed by Karl Ernst von Baer
Statement 2: He noted that embryos never pass through the adult stages of other animals.
Both are correct
…………… and…………. are the two key concepts of Darwinian Theory of Evolution
Branching descent
natural selection
………… is the end result of the ability to adapt and get selected by nature.
Fitness
Before Darwin a French naturalist………. had said that evolution of life forms had occurred but driven by use and disuse of organs
Lamarck
When we describe the story of this world we describe evolution as a process. And when we describe the story of life on earth, we treat evolution as a consequence of a process called natural selection
True
It is possible that the work of…….. on populations influenced Darwin
Thomas Malthus
Natural selection is based on certain observations which are factual
(4) in NCERT
Natural resources are limited
Populations are stable in size except for seasonal fluctuation
Members of a population vary in characteristics (infact no two individuals are alike) even though they look superficially similar
Most of variations are inherited
In the first decade of twentieth century,……… based on his work on evening primrose brought forth the idea of mutations
Hugo deVries
Scientific name of evening primrose
Oenthera lamarckiana
Difference between Darwin and Hugo deVries
(5) differences
Darwin
Evolution is slow and gradual
Large difference arises in population slowly after passing it from one generation to other
Natural selection is cause of evolution
Evolution is directional
Darwinian variation are small and directional
Hugo deVries
Evolution is single step and fast
Large difference arises suddenly in population
Mutation is cause of evolution
Evolution is non directional and random
Mutations are large and random
deVries believed mutation caused speciation and hence called it………. (single step large mutation)
saltation
This principle says that allele frequencies in a population are stable and is constant from generation to generation. The gene pool (total genes and their alleles in a population) remains a constant. This is called………
genetic equilibrium
Terms and conditions for maintenance of Hardy Weinberg equilibrium or genetic equilibrium
(6) in NCERT
No genetic drift
No recombination
No natural selection
No gene flow
Yes random mating
No mutation
New genes/alleles are added to the new population and these are lost from the old population
If this happens multiple times then it leads to……….. and when same change occurs by chance, it is called………….
Gene flow
Genetic drift
Sometimes the change in allele frequency is so different in the new sample of population that they become a different species.
The original drifted population becomes founders and the effect is called………
founder effect.
Natural selection can lead to 3 fates
Stabilisation (in which more individuals acquire mean character value)
Directional change (more individuals acquire value other than the mean character value)
Disruption (more individuals acquire peripheral character value at both ends of the distribution curve)
In 1938, a fish caught in South Africa happened to be a………. which was thought to be extinct. These animals called lobefins evolved into the first……… that lived on both land and water
Coelacanth
amphibians
There are no specimens of these left with us. However, these were ancestors of modern day frogs and salamanders.
Statement 1: The amphibians evolved into reptiles.
Statement 2: They lay thick-shelled eggs which do not dry up in sun unlike those of amphibians.
Both are correct
The first mammals were like………… And they were……….
shrews
Insectivorous
There were in………….. mammals resembling horse, hippopotamus, bear, rabbit, etc
South America
Due to continental drift, when South America joined North America, these animals were overridden by North American fauna
True
Due to the same continental drift pouched mammals of Australia survived because of lack of competition from any other mammal.
True
The brain capacities were between 650-800cc.in
Homo habilis
Fossils discovered in Java in year……….revealed the Homo erectus about 1.5 mya
1891
Homo erectus had a large brain around……..
900cc
The Neanderthal man with a brain size of…….. lived in near east and central Asia
1400cc
Homo sapiens arose in…….. and moved across continents and developed into distinct races
Africa
During……….between 75,000-10,000 years ago modern Homo sapiens arose.
ice age
Pre-historic cave art developed about………years ago
18,000
One such cave paintings by Pre-historic humans can be seen at………… rock shelter in……… district of Madhya Pradesh
Bhimbetka
Raisen
Agriculture came around……… years back and human settlements started
10,000
