BIO.A.3 Bioenergetics
Topic Summary for Energy Flow in Biological Systems:
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.
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.
Energy flows through an ecosystem in one direction from primary producers to various consumers.
A food chain is a series of steps in which organisms transfer energy by eating and being eaten. Producers, such as floating algae called phytoplankton, are at the base of every food chain.
A food web is a network of all the food chains in an ecosystem. Food webs are very complex. Small disturbances to one population can affect all populations in a food web. Changes in populations of zooplankton, small marine animals that feed on algae, can affect all of the animals in the marine food web.
Each step in a food chain or food web is called a trophic level. Producers make up the first trophic level. Consumers make up higher trophic levels. Each consumer depends on the trophic level below it for energy.
An ecological pyramid is a diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web. Types of ecological pyramids are pyramids of energy, pyramids of biomass, and pyramids of numbers:
Pyramids of energy show relative amounts of energy available at different trophic levels.
Pyramids of biomass show the total amount of living tissue at each trophic level.
A pyramid of numbers shows the relative numbers of organisms at different trophic levels.
Topic Summary for Energy Flow in Biological Systems:
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.
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.
Energy flows through an ecosystem in one direction from primary producers to various consumers.
A food chain is a series of steps in which organisms transfer energy by eating and being eaten. Producers, such as floating algae called phytoplankton, are at the base of every food chain.
A food web is a network of all the food chains in an ecosystem. Food webs are very complex. Small disturbances to one population can affect all populations in a food web. Changes in populations of zooplankton, small marine animals that feed on algae, can affect all of the animals in the marine food web.
Each step in a food chain or food web is called a trophic level. Producers make up the first trophic level. Consumers make up higher trophic levels. Each consumer depends on the trophic level below it for energy.
An ecological pyramid is a diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web. Types of ecological pyramids are pyramids of energy, pyramids of biomass, and pyramids of numbers:
Pyramids of energy show relative amounts of energy available at different trophic levels.
Pyramids of biomass show the total amount of living tissue at each trophic level.
A pyramid of numbers shows the relative numbers of organisms at different trophic levels.