Evolution NCERT Flashcards
To understand the changes in flora and fauna that have occurred over millions of years on earth, we must have an understanding of the context of ______.
Origin of life
Huge _______________ comprises the universe.
Clusters of galaxies
_______ theory talks of a singular huge explosion unimaginable in physical terms.
Big Bang theory
Origin of universe is explained by __________ theory
Big Bang theory
How many billion years back the earth was formed?
About 4.5 billion years back
Name 4 gases which were released from molten mass covered surface
Water vapour, methane, carbon dioxide and ammonia
The ____________ from the sun broke up water into Hydrogen and Oxygen
UV rays
Early Greek thinkers thought life came in the form of units from outer space called?
Spores
Oparin of Russia and Haldane of England proposed that the first form of life could have come from pre-existing non-living __________________
Organic molecules (e.g. RNA, protein, etc.)
Diverse organic molecules are formed from ________________
inorganic constituents
What were the conditions of early earth?
high temperature, volcanic storms, reducing atmosphere containing CH4, NH3, etc.
Who proposed the theory of chemical evolution?
Oparin of Russia and Haldane of England
Who provided an experimental proof for chemical evolution of life in 1953?
S.L. Miller
The first non-cellular forms of life could have originated ____________ years back
3 billion
___________ are remains of hard parts of life-forms found in rocks.
Fossils
Different-aged rock sediments contain?
fossils of different life forms (who probably died during the formation of the particular sediment).
A study of fossils in different sedimentary layers indicates?
The geological period in which these life forms existed
The study of fossils show evidence for evolution. These evidence are called?
Paleontological evidence
A technique which is used to find the age of a fossil is called?
Radioactive-dating
______________________ for evolution was proposed by Ernst Heckel.
Embryological support
Embryological support for evolution was based upon the observation of -
Certain features during embryonic stage common to all vertebrates that are absent in adult
______________ and ________________ shows similarities and differences among organisms of today and those that existed years ago.
Comparative anatomy and morphology
Whales, bats, Cheetah and human (all mammals) share similarities in the _________________ of forelimbs.
Pattern of bones
_______________ structures perform different functions but they have similar anatomical structure.
Homologous structures
The same structures developed along different directions due to adaptations to different needs of species. This phenomenon is called
Divergent evolution
Give examples of homologous organs in plants.
Thorn and tendrils of Bougainvillea and Cucurbita
Homology indicates common ____________
ancestry
__________________ are not anatomically similar structures though they perform similar functions.
Analogous structures
Give an example of analogous structures.
Wings of butterfly and birds
Analogous structures are a result of -
convergent evolution
Similarities in proteins and genes performing a given function among diverse organisms give clues to _______________________
common ancestry
Man has bred selected plants and animals for agriculture, horticulture, sport or security. This type of selection is called
Artificial selection
The classical example of natural selection is -
Melanised moth
___________ can be used as industrial pollution indicators as they do not grow in polluted areas.
Lichens
Evolution is a stochastic process based on:-
chance events in nature and chance mutation in the organisms
Small black birds (well known for their remarkable diversity in beak form) found in Galapagos Island are called?
Darwin’s Finches
From the original seed-eating features, many other forms with altered beaks arose, enabling them to become _________________ and _______________________
insectivorous; vegetarian finches
The process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of geography is called?
Adaptive radiation
Give an example of adaptive radiation?
Australian marsupials
Within the Australian Island continent, a number of marsupials, each different from the other evolved from an ______________
ancestral stock
Give an example of convergent evolution?
Flippers of Penguins and Dolphins.
The two key concepts of Darwinian Theory of Evolution are-
Branching descent and natural selection
Lamarck’s theory of evolution is based on the principle that-
Evolution of life forms had occurred but driven by use and disuse of organs.
The novelty of _________ was: He asserted that variations, which are heritable and which make resource utilisation better for few (adapted to habitat better) will enable only those to reproduce and leave more progeny
Darwin
Hugo deVries work was based on?
evening primrose (Oenothera lamarckiana)
The term used for single step large mutation is?
Saltation
____________ is a specific position on a chromosome where a particular gene is located.
Locus
We can find out the frequency of occurrence of alleles of a gene or a locus by using _______________________
Algebraic equations
What does the Hardy-weinberg principle predict?
It predicts that allele frequencies in a population are stable and is constant from generation to generation
_____________________ is the condition of an allele or genotype in a gene pool (such as a population) where the frequency does not change from generation to generation
genetic equilibrium
What are the factors known to affect Hardy weinberg principle?
Gene migration or gene flow, genetic drift, mutation, genetic recombination and natural selection
The movement of genes from one group of organisms to another is called
Gene migration
______________ is the transfer of genetic variation from one population to another
Gene flow
When the change in frequency of allele occurs in a small population by chance then it is called
Genetic drift
The original drifted population becomes founders and the effect is called?
Founder effect
______________ show that pre-existing advantageous mutations when selected will result in observation of new phenotypes
Microbial experiments
Variation due to mutation or variation due to recombination during gametogenesis, or due to gene flow or genetic drift results in?
changed frequency of genes and alleles in future generation
The mechanism of how non-cellular aggregates of giant ____________ could evolve into cells with membranous envelop is not known.
Macromolecules
Invertebrates were formed and active approximately ________________ years ago
500 million
In 1938, a fish caught in South Africa happened to be a ________________ which was thought to be extinct
Coelacanth
____________ evolved into the first amphibians that lived on both land and water
Lobefins
The _______________ evolved into reptiles.
Amphibians
Some land reptiles went back into water to evolve into fish like reptiles probably __________ mya.
200
____________ was the biggest land reptile?
Tyrannosaurus rex (It was about 20 feet in height and had huge fearsome dagger like teeth)
About _______ mya, the dinosaurs suddenly disappeared from the earth.
65 million years ago
How did dinosaurs disappear from the Earth?
We do not know the true reason. Some say climatic changes killed them. Some say most of them evolved into birds.
The first mammals were like _________
Shrews
__________________ animals protect their unborn young inside the mother’s body.
Viviparous
Some mammals live wholly in water. Examples are -
Whales, dolphins, seals and sea cows
Primates were _____________________ and ____________________ that lived 15 million years ago
Dryopithecus and Ramapithecus
Ramapithecus looked more like:-
Man
Dryopithecus looked more like:-
Ape
The brain capacity of homo habilis was measured -
Between 650 to 800 cc.
The brain capacity of Homo erectus was
Around 900cc.
The ____________ man with a brain size of 1400cc lived in near east and central Asia
Neanderthal
Cave paintings by pre-historic humans can be seen at?
Bhimbetka rock shelter in Raisen district of Madhya Pradesh
On which continent Homo sapiens arose?
Africa
_______________ is the study of history of life forms on earth.
Evolutionary Biology
When we look at stars on a clear night sky we are, in a way, looking back in _______.
time
Stellar distances are measured in _________.
light years
When we see objects in our immediate surroundings we see them instantly and hence in the ______ time
present
When we see ______ we apparently are peeping into the past.
stars
The _________ is considered a unique event in the history of universe.
origin of life
Compared to universe, the earth itself is almost only a ______ .
speck
The universe is almost _________ years old
20 billion
Galaxies contain stars and clouds of _____ and _______.
gas, dust
Name two gases that formed after temperature came down due to expansion of universe.
Hydrogen and Helium
The gases condensed under __________ and formed the galaxies of the present day universe.
gravitation
Earth is present in which galaxy?
Milky way
There was no __________ on early earth.
atmosphere
Oxygen combined with _________ and ______ to form water, CO2 and others
ammonia , methane
As it cooled, the water vapor fell as rain, to fill all the __________ and form oceans
depressions
Life appeared _______ million years after the formation of earth, i.e., almost _____ billion years back
500, four
‘___________’ is still a favourite idea for some astronomers
Panspermia
Which theory proposed that life came out of decaying and rotting matter like straw, mud, etc?
Theory of spontaneous generation
__________ by careful experimentation demonstrated that life comes only from pre-existing life.
Louis Pasteur
In pre-sterilised flasks, life did not come from killed yeast while in another flask open to air, new living organisms arose from ‘killed yeast’. This experiment disproved which theory?
Spontaneous generation theory
When S.L Miller created electric discharge in a closed flask containing CH4, H2, NH3 and water vapour at 800oC, he observed formation of __________
amino acids
In similar experiments others observed, formation of sugars, nitrogen bases,_________ and ______.
pigment,fats
We have no idea about how the first __________ metabolic capsule of life arose.
self replicating
The first cellular form of life did not possibly originate till about __________ years ago
2000 million
The first cellular form of life were probably _________.
single-cells
During early stage of evolution, all life forms were in _______ environment only
water
The first form of life arose slowly through evolutionary forces from _______ molecules.
non-living
Conventional religious literature tells us about the ________________.
theory of special creation
The theory of special creation has __________ connotations.
three
According to theory of special creation, ________ was always the same since creation and will be the same in ________ also.
diversity, future
According to theory of special creation, earth is about _________ years old.
4000 years
All the ideas of theory of special creation were strongly challenged during the _________ century.
nineteenth
Charles Darwin made observations during a sea voyage in a sail ship called ____________ round the world.
H.M.S. Beagle
Charles Darwin concluded that existing living forms share ____________ to varying degrees not only among themselves but also with life forms that existed ________ of years ago.
similarities, millions
There had been __________ of different life forms in the years gone by.
extinctions
New forms of life arose at different periods of history of ________.
earth
There has been ___________ evolution of life forms.
gradual
Any population has built in variation in _____________.
characteristics
Those characteristics which enable some to survive better in natural conditions (climate, food, physical factors,etc.) would ___________ others that are less-endowed to ___________ under such natural conditions
outbreed, survive
