3.1 Autotrophs and Heterotrophs

Question 1

Definition

Autotrophs

Answer 1

Organisms that synthesize its organic molecules from simple inorganic molecules.

Called producers.

Examples: cyanobacteria, algae, plants

Question 2

List

Types of Autotrophs

2 Types

Answer 2

• Photosynthetic autotrophs
• Chemosynthetic autotrophs

Question 3

Chemoautotrophs

Details

Answer 3

Obtain the energy they need for carbon fixation from inorganic chemical reactions

Process known as chemosynthesis.

All known chemosynthetic organisms are prokaryotes.

Question 4

Chemoautotrophs

3 example reactions

Answer 4

Chemosynthetic organisms reactions include the oxidation of inorganic molecules like:

• Ammonium ions to nitrite ions
• Nitrite ions to nitrate ions
• Sulfide ions to sulfate ions

Question 5

Chemoautotrophs

Environment

Answer 5

Hydrothermal vents – chemoautotrophs are able to survive using the molecules in the gases
Methanogens – live in anaerobic environments converting simple inorganic molecules into methane

Question 6

Definition

Heterotrophs

Answer 6

Organisms that obtain organic molecules from other organisms (autotrophs or heterotrophs).

Called consumers.

Heterotrophs depend directly or indirectly on autotrophs for energy and nutrients

Can be divided based on diet:

* Omnivorous
* Carnivores
* Herbivores

Question 7

Definition

Saprotrophic heterotrophs

Answer 7

Obtain organic nutrients from dead organisms by external digestion. Example: Mushrooms

Question 8

Detritivores

Answer 8

Heterotrophs that obtain organic nutrients from detritus (non-living particulate organic material) by internal digestion.

Example: worms

Question 9

Parasites

Answer 9

They derive their energy and nutrients directly from another living organism. The host is usually harmed or killed in the process.

Question 10

Endoparasites

Answer 10

Live inside the host

Examples include tapeworms and liver flukes.

Question 11

Ectoparasites

Answer 11

Live outside of the host

Examples include ticks and lice