In increasing order of organizational complexity, which one of the following is the correct sequence?

Options

A. Species, population, community, ecosystem
B. Population, species, community,ecosystem
C. Population, ecosystem, species, community
D. Species, population, ecosystem, community

Answer

To determine the correct sequence of organizational complexity in biology, we need to understand the definitions and relationships between the terms: population, species, community, and ecosystem.

### Step-by-Step Solution:

1. **Define Population**:
- A population is defined as a group of individuals of the same species that live in a specific area at the same time. This is the most basic level of organization.

2. **Define Species**:
- A species is a group of organisms that can interbreed and produce fertile offspring. It encompasses one or more populations that share similar characteristics.

3. **Define Community**:
- A community consists of multiple populations of different species that live together in a particular area and interact with one another. This level of organization is more complex than just a single species or population.

4. **Define Ecosystem**:
- An ecosystem includes all the living organisms (biotic factors) in a particular area, along with the non-living (abiotic) components of that environment, interacting as a system. It represents the highest level of organizational complexity among the options given.

5. **Arrange in Increasing Order**:
- Based on the definitions:
- Population (group of individuals of the same species)
- Species (group of populations that can interbreed)
- Community (assemblage of different species)
- Ecosystem (community plus abiotic factors)

Thus, the correct sequence in increasing order of organizational complexity is: **Population → Species → Community → Ecosystem**.

### Final Answer:
The correct option is **Population, Species, Community, Ecosystem**.

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