Living Things and the Environment

Living Things and the Environment

Guiding Questions:
How are populations affected by changes to the amount and availability of resources?

How are population size and resource availability related?

Draw

Circle the nonliving parts of this habitat.

Open Ended

Why are the things you selected in the previous question considered nonliving? Why do organisms need them?

Draw

Circle the living parts of this habitat.

Organisms and Habitats

At the watering hole shown in the previous pictures, animals such as giraffes stop to quench their thirst. A giraffe is an organism, or living thing. Different types of organisms live in different types of surroundings, or environments. An organism gets food, water, shelter, and other things from its environment that it needs to live, grow, and reproduce. These are called resources. An environment that provides the things a specific organisms needs to live, grow, and reproduce is called a habitat.

Organisms and Habitats

In nature, every organism you see in particular habitat is there because that habitat meets the organism's needs. Some organisms have the ability to move from one habitat to another as conditions change or as different needs arise, but many organisms stay in the same habitat for their entire lives. The living things in a particular environment and the interactions among them define the habitat and its conditions.

What types of living things are in the python's tropical rain forest habitat? The parts of a habitat that are or were once alive are called biotic factors. These biological components include the trees and plants. Animals that the python eat are biotic factors, as are other snakes it encounters. Waste products made by these organisms and others are also considered biotic factors. Bacteria, mushrooms, and other small organisms are other types of biotic factors that play important roles in the habitat.

​

​Biotic Factors

​Abiotic Factors

Organisms also interact with nonliving things in the environment. Abiotic factors are the nonliving parts of an organism's habitat. These physical components include water, oxygen, space, rocks, light, temperature, and soil. The quality and condition of the abiotic factors can have a major effect on living things. For example, water in a habitat may contain pollutants. The poor quality of water may result in sickness or death for the organisms that live there.

Open Ended

Why do you think snakes do not live in the Arctic tundra? use evidence from what you've read to support your answer.

Ecosystem Organization

Most organisms do not live alone in their habitat Instead, organisms live together in populations and communities that can also occur among the various populations.

All of the Indian pythons that live in South Asia are members of one species. A species is a group of organisms that can mate with each other and produce offspring.

​

Organisms

All the members of one species living in a particular area are referred to as a population. The Indian pythons of India's Keoladeo National Park, for example, are one example of a population.

​

Populations

A particular area usually contains more than on species of organism. The Keoladeo Park is home to hundreds of bird species, as well as mammals, plants, and other varieties of organisms. All the different populations that live in an area make up a community.

​

Communities

The community of organisms that lives in a particular area, along with the nonliving environment, make up an ecosystem. The study of how organisms interact with each other is called ecology.​

Ecosystem

​A single individual in an ecosystem is the organism, which forms a population with other members of its species. Different species form communities in a single ecosystem.

​

Levels of Organization

Open Ended

Make a prediction about how a lack of resources in an ecosystem might impact the levels of organization.