Organisms and Populations — BIOLOGY STD 12 Science — Question

Explain with the help of two examples, how certain plants have evolved morphological and chemical defenses against primary consumers such as cows and goats.

Community Service department of your school plans a visit to a slum area near the school with an objective to educate the slum dwellers with respect to health and hygiene.

1. Why is there a need to organize such visits?
2. Write the steps you will highlight, as a member of this department, in your interaction with them to enable them to lead a healthy life.

What is the difference between a breed and a species? Give an example for each category.

A patient complains of suffering from constipation, stomach ache, stool with blood clots and excess mucous.
The physician diagnosed it as amoebiasis, after stool test.
a. Write the scientific name of the microbe identified in the stool sample.
b. How do you think, the patient must have contracted it?
c. Write your suggestions to the patient to avoid infection in future.

1. HIV and Hepatitis B are STDs. Mention any two other ways by which they can be transmitted to a healthy person.
2. Why is early detection of STD essential? What can it lead to otherwise?

Try to trace the various components of human evolution (hint: brain size and function, skeletal structure, dietary preference etc.)

Gene therapy is an attempt to correct a genetic defect by providing a normal gene into the individual. By this the normal function can be restored. An alternate method would be to provide the gene product (protein/ enzyme) known as enzyme replacement therapy, which would also restore the function. Which in your opinion is a better option? Give reason for your answer.

Give three hypotheses for explaining why tropics show greatest levels of species richness.

Draw a diagram of a male gametophyte of an angiosperm. Label any four parts. Why is sporopollenin considered the most resistant organic material?

Answer the following questions:
How are pea seeds different from castor seeds with respect to endosperm?