Q51-1TYU - Campbell Biology

Question

Which of the following is true of innate behaviors? 

(A) Their expression is only weakly influenced by genes. 

(B) They occur with or without environmental stimuli. 

(C) They are expressed in most individuals in a population. 

(D) They occur in invertebrates and some vertebrates but not mammals. 

Step-by-Step Solution

Answer

1. The statement “their expression is only weakly influenced by genes” is true. 

2. The statement “they occur with or without environmental stimuli” is false. 

3. The statement “they are expressed in most individuals in a population” is false.

4. The statement “they occur in invertebrates and some vertebrates but not mammals” is false. 

Step 1: Animal behavior

All organisms react to their surrounding stimuli and interact with other organisms. This interaction is called animal behavior. 

Animal behavior is shaped by natural selection and helps the organism to survive. The branch of biology that deals with the behavioral study of animals is known as ethology. 

Step 2: Explanation of option ‘(A)’

Innate refers to by birth. This behavior is developed in the organism through the influence of genes. The impact of the environment on innate behavior is minimal or none at all. Fixed action patterns in all organisms are examples of innate behavior. 

Therefore, gene expressions slightly influence innate behavior, and it is pre-programmed in all animals. 

Thus, the given statement is true. 

Step 3: Explanation of option ‘(B)’

Innate behavior develops without environmental stimuli. The genes influence innate behavior which is in-built in the organism. 

Therefore, environmental stimuli in the occurrence of innate behavior are less.

Thus, the given statement is false. 

Step 4: Explanation of option ‘(C)’

Innate behavior is evident in all individuals. The ability to express, including reflexes, is an example of innate behavior. It is not limited to a certain population. 

Therefore, the phrase “expressed in most individuals” is not correct in innate behavior. It is expressed in all individuals in a population. 

Thus, the given statement is false. 

Step 5: Explanation of option ‘(D)’

Innate behavior is expressed in all organisms, including mammals. For example, the sucking instincts of human infants is an innate behavior. 

Therefore, innate behavior is also found in mammals.

Thus, the given statement is false.