Natural Selection_Unsolved Paper
Chapter: Heredity and Evolution | Topic: Natural Selection
NATURAL SELECTION_UNSOLVED PAPER
Topic: Natural Selection
Q1. Natural selection refers to the process in which:
- All organisms change according to their wishes
- Individuals with favourable inherited variations are more likely to survive and reproduce
- Organisms stop producing variations
- Every organism has an equal chance of survival regardless of its characteristics
Q2.Which factor is most important for natural selection to occur?
- Presence of variations in a population
- Complete similarity among individuals
- Unlimited resources
- Absence of reproduction
Q3. If a particular inherited variation helps an organism survive better in its environment, that organism is more likely to:
- Reproduce successfully
- Lose the variation immediately
- Stop competing for resources
- Become identical to every other organism
Q4. Natural selection generally acts on:
- Differences in characteristics among individuals
- Only the age of organisms
- Organisms' wishes and choices
- Characteristics that are never inherited
Q5. A population of insects contains individuals with different colour patterns. Birds can easily see one colour pattern but have difficulty seeing another. Over many generations, natural selection may cause:
- The less visible pattern to become more common
- All insects to lose their colour
- Every insect to develop the same colour immediately
- The insects to stop reproducing
Q6.Which statement best describes the relationship between natural selection and evolution?
- Natural selection can contribute to changes in populations over generations
- Natural selection prevents all variations
- Natural selection changes an individual organism during its lifetime
- Natural selection makes all organisms identical
Short questions
Q1. Define natural selection in simple biological terms.
Q2. Why are inherited variations important for natural selection?
Q3. How can competition for limited food and space influence natural selection in a population?
Q4. Why does natural selection act on populations over generations rather than producing an immediate change in every individual?
Q5. A school garden has two varieties of plants. One variety can survive better when water becomes scarce.
How might natural selection influence these two varieties over several generations?
Q6. Imagine a population of insects living in an agricultural field where the surroundings become darker because of changes in vegetation.
How could differences in body colour influence the survival of different insects?
Q1. Explain the process of natural selection using the following ideas: variation, struggle for existence, environmental conditions, survival, and reproduction.
Q2.Explain how a favourable inherited variation can gradually become more common in a population. Describe the process over several generations.
Q3. A population of insects has several colour variations. A change in the environment makes some colours less visible to predators than others.
Using the concept of natural selection, explain how the population might change over many generations.
Q1. A population contains 300 insects. Out of these, 90 insects possess an inherited variation that may help them survive a new environmental condition. After the environmental change, 72 of these 90 insects survive.
a) What percentage of the original population possessed the variation?
b) What percentage of the insects with the variation survived?
Q2.Two varieties of plants are exposed to a period of limited rainfall.
a) Calculate the survival percentage of each variety.
b) Which variety shows the greater survival percentage?
Q3. A population of 500 organisms contains 20% individuals with an inherited variation that provides an advantage under a particular environmental condition. After the environmental change, 70% of the individuals with this variation survive.