AP Inter 2nd Year Zoology Important Questions Chapter 7 Organic Evolution

Students get through AP Inter 2nd Year Zoology Important Questions 7th Lesson Organic Evolution which are most likely to be asked in the exam.

AP Inter 2nd Year Zoology Important Questions 7th Lesson Organic Evolution

Very Short Answer Questions

Question 1.
What are panspermia? [TS MAR-17]
Answer:

1. According to Panspermia theory of evolution, life might have existed else where in the universe (cosmos) in the form of resistant spores called panspermia .
2. The life might have reached earth accidentally.

Question 2.
Define prebiotic soup. Who coined this term?
Answer:

1. According to the “Theory of origin of life”, hydrocarbons reacted with ammonia and water to produce various simple organic molecules like sugars, amino acids, fatty acids, purines and pyrimidines which later formed nucleosides and nucleotides.
   All these reactions occurred in the ocean, which was described as the prebiotic soup.
2. This was coined by J.B.S.Haldane.

Question 3.
How did eukaryotes evolve?
Answer:
Eukaryotes evolved probably by two processes.

1. Some aerobic bacteria might have entered the anaerobic prokaryota and transformed into mitochondria and plastid hence primitive eukaryotes were produced.
2. The plasma membrane of ancestral eukaryotes might have infolded to form the endomembrane system and hence eukaryotes might have evolved.

Question 4.
What are the components of the mixture used by Urey & Miller in their experiments to simulate the primitive atmosphere?
Answer:
Urey and Miller used a mixture of water vapour, methane, ammonia and hydrogen in their experiments to simulate the primitive atmosphere.

Question 5.
Mention the names of any four connecting links that you have studied. [TS MAY-17]
Answer:
Connecting links:

1. Eusthenopteron between fishes and amphibians.
2. Seymouria between amphibians and reptiles.
3. Archaeopteryx between reptiles and birds.
4. Cynognathus between reptiles and mammals.

Question 6.
Define Biogenetic Law, giving an example. [TS MAR-17]
Answer:

1. Biogenetic law ( Theory of recapitulation): ‘Ontogeny repeats Phytogeny’. This means the developmental history of an organism repeats the evolutionary history of its ancestor.
2. Examples:
   (i) Caterpillar of butterfly resembles an annelid
   (ii) Tadpole larva of frog resembles a fish with a tail and a two chambered heart and gills.

Question 7.
Define atavism with an example. [TS MAR-1611 TS MAY-17]
Answer:

1. Atavism: Sudden reappearance of some vestigial organs in a better developed condition is called atavism.
2. Ex: Human baby bom with tail

Question 8.
Cite two examples to disprove Lamarck’s inheritance of acquired characters.
Answer:
Ex 1: Well developed muscles of athletes are not inherited to their children
Ex 2: It has been a practise in India that ear pinnae are pierced for ornaments, but that character is not inherited to any child.

Question 9.
Who influenced Darwin most, in formulating the idea of Natural Selection?
Answer:
In formulating Natural Selection Darwin was influenced by

1. ‘An essay on the principles of populations’- T.R Malthus
2. ‘Principles of geology’ – Charles Lyell.
3. ‘On the tendencies of varieties to depart from original types’ – Alfred Russel Wallace.

Question 10.
What is common between Darwinism and Lamarckism?
Answer:

1. Presence of variations is common to Darwinism and Lamarckism.
2. Lamarckism is the first scientific assumption that recognised the “adoption to the environment” as a primary product of evolution. Darwinism also says that during straggle for existence, the organisms with beneficial variations alone will survive.

Question 11.
What is meant by genetic load? (five an example.
Answer:

1. Cenetic toad: Existence of deleterious genes with in a population is called genetic load.
   Ex: Sickle cell anaemia.
2. People with homozygous (both recessive genes) condition of this gene die early due to anaemia.
3. People with heterozygous (one dominant and one recessive) condition live some more years and exhibit resistance to malaria.

Question 12.
Distinguish between allopatric aru. sympatric speciations.
Answer:

Allopatric speciation	Sympatric speciation
If the speciation takes place due to geographical isolation it is called allopatric speciation.	If the speciation takes place in the same habitat but isolation due to interbreeding it is called sympatric speciation.

Question 13.
Mention the scientific names of ape like and man like earlier primates. Which man like primate first used hides to cover the bodies?
Answer:

1. Ape like man – Dryopithecus .
2. Man like earlier primate – Ramapithecus
3. Man like primate who first used hide to cover the body – Homoneanderthalensis.

 

Short Answer Questions

Question 1.
Distinguish between homologous and analogous organs. [TS MAY-17] [AP MAR-17,151 [ TS MAR-15]
Answer:
Homologous organs

1. The organs which have similar structure and origin but not necessarily the same function are called homologous organs.
2. Such organs show adaptive radiation (or) divergent evolution.
3. Ex: The forelimbs of vertebrates, Flipper of Whale, hand of man and wings of bat
4. All these organs have same arrangement of bones but their functions vary to suit their mode oflife.

Analogous organs

1. The organs which have different origin but have same function are analogous organs.
2. They suggest convergent evolution.
3. Ex: Wings of butterfly and wings of birds.
4. When the animals live in same habitat and lead a similar mode oflife they tend to have same body form.

Homologous and Analogous organs are evidences of evolution from comparative anatomy.

Question 2.
Write a short note on the theory of mutations. [APMAR-15]
Answer:

1. Mutations: These are sudden, random inheritable changes that occur in organisms.
2. Mutation theory was proposed by Hugo de Vries.
3. He worked on Oenothera lamarckiana, commonly called evening primrose.
4. He found four different forms of Oenothera, Lamarckiana (evening primrose)
   (i) Small style form – O.brevistylis.
   (ii) Smooth leaves form – O.levifolia
   (iii) Giant form – O.gigas
   (iv) Dwarf form – O.nanella
5. All the four forms are mutant forms.
6. Darwin called mutations as sports of nature.
7. Bateson called them as discontinuous variations.

Salient features of Mutation theory:

1. Mutations occur from time to time in a naturally breeding population.
2. They are discontinuous and not accumulated over generation.
3. They are full-fledged and there are no intermediate forms.
4. They are subjected to natural selection.

Question 3.
Explain Darwin’s theory of Natural Selection with industrial melanism as an experimental proof. [AP MAR-17,16] [TS MAR-15,16,17,19]
Answer:

1. Darwin’s theory of natural selection explains how evolution might have occurred in nature.
2. A classical example for natural selection is industrial melanism, exhibited by peppered moth-Biston betularia.
3. These moths were available in two colours grey and black.
4. Grey moths were abundant before industrial revolution in all over England.
5. But after the establishment of industries in England, black coloured moths were more and grey forms were less.
6. This is due to pollution from industries in the form of soot turned barks of trees into black.
7. So grey moths were easily identified and were more predated by birds.
8. Thus grey moths decreased in number, black moths increased in the population.
9. Thus natural selection favoured the melanic moths (black) to reproduce more successfully.
10. Natural selection of darker forms in response to industrial pollution is known as industrial melanism.

Question 4.
Discuss the role of different patterns of selections in evolution.
Answer:
Natural selection as an evolutionary force is of three types.
1) Stabilising selection: It operates in a stable environment. In this type the organisms having average phenotype are preserved. The individuals with extreme phenotypes are eliminated. Thus the stabilising selection does not promote evolutionary change. It maintains the phenotypic stability over generations.
Ex: In England weights of new bom babies were studied.
Greater mortality was found in babies whose weight was either greater or lesser than average weight of 8 pounds.

2) Directional selection: This selection operates in a gradually changing environment. It constantly eliminates individuals from one’end. The average values are constantly shift to the other favourable end.
Ex 1 : In Giraffes the average value is the length of the neck towards long neck.
Stabilising selection takes over the directional selection when the phenotype coincides the new environment (Head reaching the top of the trees).
Ex 2: Resistance to DDT by mosquito: The mosquitos which are resistant to DDT survived and produced DDT resistant mosquito. The other non resistant type eliminated.

 

3) Disruptive selection: This selection operates when homogenous environment changes into heterogeneous type. The organisms with extreme phenotype survive and grow into separate populations. It is also called adaptive radiation.
Ex: Dark and grey peppered moths. Darwin’s finches with different shaped beeks, sunflower populations of California which formed in dry land and Wet land types. Where there is no inter breeding it is certain that new species have evolved.

Question 5.
Write a short note on Neo – Darwinism. [AP MAR-20]
Answer:
Fisher, Sewall Wright and Mayr explained natural selection in the light of post Darwinian discoveries. According to Neo Darwinism or modem synthetic theory five basic factors are involved in the process of organic evolution. They are as follows:
1) Gene mutations: Change in the structure of DNA is called gene mutation or point putation. Any change in DNA alter the phenotype, to produce variations in offspring.

2) Chromosomal mutations: Addition, deletion, inversion and translocation of chromosome come under chromosomal mutation. They alter the phenotype.

3) Genetic recombination: During meiosis exchange of chromosomal bits and genes take place and produce heritable variations.

4) Natural selection: It favours some variations and rejects other, The selected variations continue in the next generations.

5) Reproductive isolation: Any reason which stops interbreeding in groups of a population is called reproductive isolations. The groups of a population which donot inter breed with other groups grow into separate species.

Question 6.
In a population of 100 rabbits w hich is in Hardy – Weinberg equilibrium, 24 are homozygous long – eared. Short ears are recessive to long ears. There are only two alleles for this gene. Find out the frequency of recessive allele in the population.
Answer:
Total population of Rabbits -100 Homozygous long eared is – 24.
Short ears are recessive
To find recessive allelic frequency:
Frequency of dominant genotype

No. of dominant individuals =
Total number of individuals 100
P² = 0.24 ⇒ P = √24 = 0.49 (approximately)
p+q = 1 (where p is dominant alleclic frequency and q is recessive allelic frequency)
q = 1-p = 1 – 0.49 = 0.51
Recessive frequency of Rabbits = 0.51.

Question 7.
What is meant by genetic drift? Explain genetic drift citing the example of Founder Effect. [AP MAR-16,19]
Answer:
1) Genetic Drift: The change in the frequency of a gene that occurs merely by chance and not by selection in small populations, is called genetic drift.

2) A gene is with two alleles. If the frequency of a particular gene is 1%, the probability of losing that allele by chance from the small population is more. The end result is either fixation or loss of that allele. The probability of reaching the end point depends on the size of population.

3) Genetic drift tends to reduce the amount of genetic variation within the population, mainly by removing the alleles with low frequencies. Genetic drift can be exemplified by the founder effect.

4) Founder effect: If a small group of individuals from a population start a new colony in an isolated region, those individuals are called the founders of the new population. The allelic frequency of their descendants are similar to those of the founders rather than to either ancestral parent population.
Ex: Presence of 0+ve blood group is nearly 100% in Red Indians. The forefathers of the Red Indian tribe were predominantly 0+ve and they isolated themselves reproductively from other populations.

Multiple Choice Questions

Question 1.
According to Darwin, evolution is
1. Sports or saltations
2. descent with modification
3. Roll out
4. Unfolding
Answer:
2. descent with modification

Question 2.
Basic principal of Lamarckism is
1. Inheritance of acquired character
2. Survival of the fittest
3. Natural selection
4. Variations
Answer:
1. Inheritance of acquired character

Question 3.
Cosmozoic theory was put forward by
1. Father Suarez
2. Arrhenius
3. Louis Pasteur
4. Cuvier
Answer:
2. Arrhenius

Question 4.
Darwin’s theory of Natural selection
1. did not account for fossil
2. was the first scientific theory of evolution
3. failed to explain the origin mechanism of the variations
4. was replaced by ‘mutation theory’
Answer:
3. failed to explain the origin mechanism of the variations

Question 5.
Darwin called macrovariations as
1. Mutations
2. Discontinuous variations
3. Sports of nature
4. Jumps
Answer:
3. Sports of nature

Question 6.
Darwin proposed that new species evolve from ancestral forms by
1. Gradual accumulation of adaptations to changing environment
2. Inheritance of acquired adaptation to the environment
3. Struggle for limited resources
4. Accumulation of mutations
Answer:
1. Gradual accumulation of adaptations to changing environment

Question 7.
One major criticism of Darwin’s theory is
1. It presumes that environment upon earth has been changing through ages
2. It does not explain variations with heredity
3. It overestimates reproductive capacity of animals and plants
4. It does not explain vestigial organs
Answer:
2. It does not explain variations with heredity

 

Question 8.
The first modern birds appeared during
1. Cretaceous period
2. Jurassic period
3. Triassic period
4. Carboniferous period
Answer:
1. Cretaceous period

Question 9.
Dinosaurs disappeared during
1. Jurassic
2. Triassic
3. Creataceous
4. Permian
Answer:
3. Creataceous

Question 10.
Similarities in organisms with different genotype indicate
1. Microevolution
2. Macroevolution
3. Convergent evolution
4. Divergent evolution
Answer:
3. Convergent evolution

Question 11.
Genetic drift operates in
1. Small isolated population
2. Large isolated population
3. Fast reproductive population
4. Slow reproductive population
Answer:
1. Small isolated population

Question 12.
According to abiogenesis, the new life might have originated from
1. Nonliving substances
2. Preexisting organisms
3. Inorganic matter
4. Cosmozoa
Answer:
1. Nonliving substances

Question 13.
The term ‘organic evolution’ is coined by
1. Lamarck
2. Darwin
3. H.Spencer
4. Devries
Answer:
3. H.Spencer

Question 14.
The idea of ‘Survival of the fittest’ was proposed by
1. Herbert Spencer
2. Charles R.Darwin
3. J.B.de Lamarck
4. Hugo de Vries
Answer:
1. Herbert Spencer

Question 15.
The sum total of genes in a Mendelian population constitutes
1. Genome
2. Genotype
3. Gene pool
4. Genetic variation
Answer:
3. Gene pool

Question 16.
The scientist who studied mutations scientifically for first time is
1. Darwin
2. Herbert Spencer
3. De Vries
4. Lamarck
Answer:
3. De Vries

Question 17.
In evolution, the mutation occurs in
1. RNA
2. Nucleus
3. Protoplasm of somatic cells
4. DNA of sex cells
Answer:
4. DNA of sex cells

Question 18.
Industrial melanism is an example of
1. Natural selection
2. Mutation
3. Adaptive convergence
4. Artificial selection
Answer:
1. Natural selection

Question 19.
Primitive atmosphere was made up of
1. Oxygen, ammonia, methane, water
2. Hydrogen, ammonia, methane, oxygen
3. Hydrogen, steam, methane, ammonia
4. Oxygen, methane, water, nickel
Answer:
3. Hydrogen, steam, methane, ammonia

Question 20.
Primitive atmosphere was reducing because
1. Hydrogen atoms were few
2. Hydrogen atoms were active and in greater number
3. Nitrogen atoms were more
4. 0xygen atoms were more
Answer:
2. Hydrogen atoms were active and in greater number

Question 21.
Archaeopteryx is a connecting link because
1. it possessed characters of reptiles and aves
2. it had characters of reptiles and mammals
3. it was a reptile not a bird
4. it had characters of non chordates and chordates
Answer:
1. it possessed characters of reptiles and aves

Question 22.
According to recapitulation theory
1. every animal begins as an egg
2. damaged body parts are formed new
3. offsprings are like parents
4. ontogeny repeats plylogeny
Answer:
4. ontogeny repeats plylogeny

Question 23.
Which of the following has homologous organs
1. Hands of man, monkey and kangaroo and trunk of elephant
2. Wings of insects, birds and bats
3. Hindi limbs of grasshopper, horse and bat
4. Mouthparts of cockroach, mosquito and honey bee
Answer:
4. Mouthparts of cockroach, mosquito and honey bee

Question 24.
Fossils are dated by
1. Amount of calcium residue
2. Amount of radioactive carbon compound
3. Association with other mammlas
4. Structure of bones
Answer:
2. Amount of radioactive carbon compound

Question 25.
Homo erectus is different from Cro-magnon man in having
1. Jaws protruding out
2. Tool making
3. Slopping jaws
4. Arts and paintings
Answer:
1. Jaws protruding out

Question 26.
The first ancestor of man whose fossils have been discovered was
1. Pithecanthropus
2. Zinjanthropus
3. Australopithecus
4. Neanderthal man
Answer:
3. Australopithecus

Question 27.
Sources of energy for all the chemical reactions in prebiotic soup were
1. Volcanic activities
2. U-V rays and other radiations
3. Lightening
4. All the above
Answer:
4. All the above

Question 28.
The free genes started absorbing the organic compounds from the prebiotic soup and < evolved into
1. Anaerobic autotrophs
2. Aerobic heterotrophs
3. Aerobic protobionts
4. Anaerobic heterotrophs
Answer:
4. Anaerobic heterotrophs

Question 29.
The mouth parts of all insects contain the similar structures, so they are
1. Analogous organs
2. Homologous organs
3. Vestigial organs
4. Atavistic organs
Answer:
2. Homologous organs

Question 30.
Pcripatus is a connecting link between
1. Ctenophora and Platyhelminthes
2. Mollusca and Echinodermata
3. Annelida and Arthropoda
4. Coelenterata and Porifera
Answer:
3. Annelida and Arthropoda

Question 31.
Serological tests or blood precipitation tests are conducted by
1. J.Needham
2. Haeckel
3. Von Baer
4. H.F. Nuttal
Answer:
4. H.F. Nuttal

Question 32.
The correct chronological sequence of Eras is
1. Mesozoic → Coenozoic → Archaeozoic
2. Coenozoic → Proterozoic → Mesozoic
3. Palaeozoic → Mesozoic → Coenozoic
4. Palaeozoic → Archaeozoic → Coenozoic
Answer:
3. Palaeozoic → Mesozoic → Coenozoic

Question 33.
The paper titled “On the tendency of varieties to depart from original types” was w ritten by
1. Charles Robert Darwin
2. Alfred Russel Wallace
3. Victor Hugo de Vries
4. Sir Charles Lyell
Answer:
2. Alfred Russel Wallace

Question 34.
KettleweIJ’s experiment explains
1. Inheritance of acquired characters in moths
2. Differential survival of the moths
3. Overproduction in moths
4. Use and disuse in moths
Answer:
2. Differential survival of the moths

Question 35.
Which of the following is not a condition for Hardy-Weinberg equilibrium?
1. Large size of population
2. No mutation
3. No large-scale migrations
4. Non-random matings
Answer:
4. Non-random matings

Question 36.
Type of natural selection that leads to phenotypic polymorphism in a species is
1. Normalising selection
2. Directional selection
3. Disruptive selection
4. Mass selection
Answer:
3. Disruptive selection

Question 37.
Geographic isolation is not required for the occurrence of
1. Allopatric speciation and founder effect
2. Allopatric speciation and bottleneck effect
3. Sympatric speciation and founder effect
4. Sympatric speciation and bottleneck effect
Answer:
4. Sympatric speciation and bottleneck effect

Question 38.
Evolution of heart from one to two, three and four chambered proves
1. Biogenetic law of Haeckel
2. Lamarckism
3. Hardy weinberg’s law
4. Neo Darwinism
Answer:
1. Biogenetic law of Haeckel

Question 39.
The most significant trend in the evolution of modern man (Homo sapiens) from his ancestors was
1. Increasing cranial capacity
2. Uprigth posture
3. Shortening of jaws
4. Binocular vision
Answer:
1. Increasing cranial capacity

Question 40.
Embryological support for evolution was disapproved by
1. Karl Ernst Von Baer
2. Alfred Wallace
3. Charles Darwin
4. Oparin
Answer:
1. Karl Ernst Von Baer