Question

The trophic relationships between species in a habitat can be represented in the form of a food web matrix where, rows represent consumers/ predators, and columns represent resources/prey. If the organism of a species in the row eats the organism of a particular species in the column, then a `1' is placed in the intersection. Otherwise a `0' is placed in the intersection. Such a matrix for species M - Q is given below.

Based on the matrix, the correct statement is:

• A. Species P is both a secondary and tertiary consumer.
• B. Scarcity of species M can directly affect primary consumers O and P.
• C. There are two producer species in this ecosystem.
• D. Species N is an omnivore.

Hint:

To find the trophic level of any consumer, write out all the possible pathways starting from the producer (M): Pathway 1: $M \rightarrow N \rightarrow P$ (P is a secondary consumer) Pathway 2: $M \rightarrow N \rightarrow O \rightarrow P$ (P is a tertiary consumer).

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
This question asks to identify the correct statement about the trophic relationships in a food web using a provided resource-consumer interaction matrix.

Step 2: Detailed Explanation:

• Let us analyze the rows (consumers) and columns (resources/prey) of the given matrix: itemize

• A value of '1' at the intersection of a row and column means the species in the row eats the species in the column.

• Species M has '0' across all columns, meaning it does not consume any other species in this matrix. Thus, Species M is a primary producer.

• Species N consumes only Species M (indicated by '1' in the M column). Since it eats a producer, Species N is a primary consumer (herbivore).

• Species O consumes both Species M (producer) and Species N (primary consumer). Since it eats both a producer and a consumer, Species O acts as both a primary consumer and a secondary consumer (omnivore).

• Species P consumes Species N (primary consumer) and Species O (which can act as a secondary consumer). When P eats N, P acts as a secondary consumer. When P eats O (acting as a secondary consumer), P acts as a tertiary consumer. Thus, Species P is both a secondary and a tertiary consumer.

• Species Q consumes only Species M, making it a primary consumer.

Let us evaluate the options:

• Option A matches our deduction that Species P acts as both a secondary and a tertiary consumer.

• Option B is incorrect because Species P does not consume Species M directly.

• Option C is incorrect because only Species M acts as a producer (all 0s).

• Option D is incorrect because Species N only eats M, making it a specialist herbivore, not an omnivore.

itemize

Step 3: Final Answer:
Therefore, Species P is both a secondary and tertiary consumer.