B1.6 - Waste Materials from Plants and Animals Flashcards
Why do living things remove materials from the environment?
For growth and other processes
How are these materials returned to the environment?
In waste materials or when living things die and decay
Why do materials decay?
They are broken down by microorganisms
When are microroganisms most active?
In warm, moist aerobic conditions
What does the decay process release?
substances that plants need to grow
What happens in a stable community?
Materials are constantly cycled, the processes that remove materials are balanced by the processes that return them.
What is the carbon cycle?
The cycling of carbon in an environment
How is carbon dioxide removed form the environment?
By green plants and algae for photosyntheis
How is carbon dioxide used by plants?
To make carbohydrates, fats and protiens
What happens when plants and animals are eaten by animals and the animals are eaten by other animals?
Some of the carbon becomes part of the fats and proteins that make up their bodies
What happens when the animals respire?
Some of the carbon in their bodies becomes carbon dioxide and is released int the atmosphere
What happens when plats and animals die?
Microorganisms feed on their bodies, and produce carbon dioxide when they respire
What happens by the time that microorganisms have broken down the waste products of dead bodies and cycled the materials as plant nutrients?
All the energy originally absorbed by green plants has been transferred
What else releases carbon dioxide into the atmosphere?
Combustion of wood and fossil fuels
