Free Heredity and Evolution 03 Practice Test - 10th Grade
Question 1
When a gene exists in more than one form, the different forms are termed as_______.
alleles
SOLUTION
Solution : A
All copies of a gene are not identical and alternative forms of a gene are called alleles. They lead to the alternative or different forms of one trait.
Question 2
Genetic variation affects the evolution of populations.
True
False
SOLUTION
Solution : A
Genetic variation is a measure of the genetic differences that exist within a population. It is the basic phenomenon on which environmental forces act to create evolution among populations.
Question 3
The diagram below represents a section of undisturbed layers of sedimentary rocks. It shows the location of fossils of several closely related species. According to currently accepted evolutionary theory, which is the most probable assumption about species A, B, and C?
Species B is less abundant than species C
Species C existed before species B
Species A and B are genetically identical
Species B descends from species A
SOLUTION
Solution : B
Following conclusions can be drawn by observing the figure.
1. Species A is the most recent species because it is located on top.
2. Species B is more abundant than species C as its fossils are found in two layers of the sedimentary rock.
3. Deeper the layers, older are the fossils. So, fossils of species C are older than the fossils of species B. Thus, species C existed before species B.
Different layers of earth provide information about geological time scale. Scientists link the fossils and the geological time scale information to know the time of existence of those species.
Question 4
Common origin of man and chimpanzee is best shown by ________ .
SOLUTION
Solution : C
Common origin of man and chimpanzee is best shown by DNA similarity. According to DNA studies, DNA of humans and chimpanzees is 98% similar. Humans and chimpanzees share a common ancestry.
Question 5
The evolution of vegetable broccoli belonging to the cabbage family is an example of ______ .
SOLUTION
Solution : B
Broccoli has been cultivated from wild cabbage by the method of artificial selection by the farmers. Green coloured flowering heads of broccoli are edible. The wild cabbage was bred and selected for this character to get broccoli.
Question 6
Human baby will be a male if its 23rd chromosome pair is ____.
SOLUTION
Solution : B
Humans contain 22 pairs of autosomes and 1 pair of sex chromosomes. The female gamete or the egg consists of an “X” chromosome. If this is fertilised by a sperm containing “X” chromosome, the baby will have “XX” chromosome and will be a female. But if the egg is fertilised by a sperm containing “Y” chromosome, the baby will have “XY” chromosome and will be a male.
Question 7
Consider the following statements -
-
Evolution is simply the generation of diversity and the shaping of the diversity is by environmental selection.
- Human beings are not the pinnacle of evolution, but simply yet another species in the teeming spectrum of evolving life.
SOLUTION
Solution : C
Evolution is the process by which lot of diverse organisms are formed from earlier organisms over a span of millions of years. Humans are simply one more species in this spectrum of evolution of life on earth. We are not the last and ultimate of evolution. There could be more in evolution that can happen. All other organisms have their own status in evolution as well.
Question 8
Which of the following is/are example/s of homologous organs?
SOLUTION
Solution : A and B
Homologous organs are those which have similar structure and origin but different function. Forelimbs of a dog and flippers of whale have similar structure and origin but they serve a different funtion, thus, homologous. Similarly, arms of a rabbit and a human are homologous organs.
Wings of a moth and a bird, although serve a common function, do not share a similar structure and hence analogous. Same is the case with limbs of a lizard and a crab.
Question 9
The differences found between various individuals of the same species is referred to as ______.
SOLUTION
Solution : B
Variation is the degree of differences in the progeny and between the progeny and the parent. Variations can be seen either in the morphological appearance (phenotype) or the genetic makeup (genotype) of an organism.
Question 10
The figure below depicts a situation where a rare variation has become common. The green coloured beetle population has become common because it gave them a survival advantage. This is an example of ______
SOLUTION
Solution : B
When a population of a particular variant organism increases due to a survival advantage, it is the natural selection. In this case, green beetles cannot be seen by the crow and therefore, their population has grown compared to the red coloured beetles. Thus, natural selection pressure is exerted by crows.