Problem 7 - Campbell Biology

Question

The black dots that cover strawberries are actually fruits formed from the separate carpels of a single flower. The fleshy and tasty portion of a strawberry derives from the receptacle of a flower with many separate carpels. Therefore, a strawberry is (A) a simple fruit with many seeds. (B) both a multiple fruit and an accessory fruit. (C) both a simple fruit and an aggregate fruit. (D) both an aggregate fruit and an accessory fruit.

Step-by-Step Solution

Answer

(D) both an aggregate fruit and an accessory fruit.

Step 1: Understanding Fruit Terminology

To solve this exercise, it's important to understand the different types of fruits mentioned: simple fruit, multiple fruit, aggregate fruit, and accessory fruit.

Step 2: Define Simple Fruit

A simple fruit develops from a single ovary of one flower.

Step 3: Define Multiple Fruit

A multiple fruit forms from the ovaries of multiple flowers that are packed closely together.

Step 4: Define Aggregate Fruit

An aggregate fruit develops from multiple ovaries of a single flower.

Step 5: Define Accessory Fruit

An accessory fruit includes other floral parts in addition to the ovary. This means parts such as the receptacle can make up the flesh of the fruit.

Step 6: Analyze Strawberry Characteristics

Strawberries have seeds on the surface that originate from multiple ovaries in a single flower, meaning they are aggregate fruits. The fleshy part of a strawberry comes from the receptacle, indicating it is also an accessory fruit.

Step 7: Determine the Correct Answer

Given that strawberries meet the criteria for both an aggregate fruit and an accessory fruit, the correct answer is option (D).

Key Concepts

fruit types

Fruits are diverse and can be categorized into different types based on their development. This categorization helps botanists and students understand how different fruits form and what parts of the flower contribute to them.

Here are some key types of fruits:

• Simple Fruit: These fruits develop from a single ovary of one flower. Examples include peaches and tomatoes.
• Multiple Fruit: These form from the ovaries of multiple flowers, which are closely packed together. Pineapples are a typical example.
• Aggregate Fruit: Develops from multiple ovaries of a single flower. Strawberries and blackberries fall into this category.
• Accessory Fruit: Includes other floral parts in addition to the ovary. Apples and pears are good examples.

Understanding these categories is crucial for identifying and classifying different fruits.

aggregate fruit

An aggregate fruit forms from a single flower that has multiple ovaries. Unlike simple fruits, which come from a single ovary, aggregate fruits are composed of tiny fruitlets. Each fruitlet develops from one ovary, and they are clustered together to form the whole fruit.

Here are some characteristics:

• Origin: Develops from one flower with many separate carpels (ovaries).
• Appearance: Multiple smaller units are visibly grouped together.
• Example: Strawberries, where each black dot on the surface is a separate fruit formed from one ovary.

Understanding this helps explain why some fruits look like they are made of smaller pieces put together.

accessory fruit

Accessory fruits are unique because they include parts of the flower other than the ovary. This means components like the receptacle (the part of the stem on which the flower organs are attached) also contribute to the fruit.

Here are some characteristics:

• Composition: Includes other floral parts in addition to the ovary, often contributing to the flesh of the fruit.
• Example: Strawberries, where the juicy part we eat is the receptacle, not the ovaries. Another example is an apple, where the flesh comes from the floral tube and the core from the ovary.

Knowing this concept helps understand how different parts of the flower can end up being the edible portions of the fruit.