Name KEY Class Date
3.2 Energy, Producers, and Consumers
Lesson Objectives
Define primary producers.
Describe how consumers obtain energy and nutrients.
Lesson Summary
Primary Producers Sunlight is the main energy source for life on Earth. Organisms that
can capture energy from sunlight or chemicals and use that energy to produce food are called
autotrophs, or primary producers.
The process in which autotrophs capture light energy and use it to convert carbon dioxide
and water into oxygen and sugars is called photosynthesis.
The process in which autotrophs use chemical energy to produce carbohydrates is
called chemosynthesis.
Consumers Organisms that rely on other organisms for their energy and food are called
heterotrophs. Heterotrophs are also referred to as consumers. There are many different types
of heterotrophs:
Herbivores, such as cows, obtain energy by eating only plants.
Carnivores, such as snakes, eat only animals.
Omnivores, such as humans, eat both plants and animals.
Detritivores, such as earthworms, feed on dead matter.
Decomposers, such as fungi, break down organic matter.
Scavengers, such as vultures, consume the carcasses of other animals.
Primary Producers
1. What do autotrophs do during photosynthesis?
Use light energy to convert inorganic molecules (water and carbon dioxide) into
Energy rich carbohydrates like glucose.
2. Can some organisms survive without energy from the sun? Explain your answer.
YES. We call them chemotrophs/chemoautotroph.
3. Can organisms create their own energy? Explain your answer.
No. Producers use energy from the sun. Heterotrophs must consume energy
from other organisims
