10.3 Study Guide

Question 1

Trophic Levels

Answer 1

Trophic level is defined as the position of an organism in the food chain and ranges from a value of 1 for primary producers to 5 for marine mammals and humans.

Question 2

Autotroph

Answer 2

An autotroph is an organism that can produce its own food using light, water, carbon dioxide, or other chemicals. Because autotrophs produce their own food, they are sometimes called producers.

Question 3

Heterotroph

Answer 3

A heterotroph is an organism that eats other plants or animals for energy and nutrients.

Question 4

Herbivore

Answer 4

A herbivore is an animal that only eats vegetation, such as grasses, fruits, leaves, vegetables, roots and bulbs. Herbivores only eat things that need photosynthesis to live. Some parasitic plants that feed on other plants are also considered herbivores.

Question 5

Omnivore

Answer 5

An omnivore is an organism that regularly consumes a variety of material, including plants, animals, algae, and fungi. They range in size from tiny insects like ants to large creatures—like people. Human beings are omnivores.

Question 6

Carnivore

Answer 6

A carnivore is an organism that mostly eats meat, or the flesh of animals.

Question 7

Detritivore

Answer 7

Common examples of detritivores include earthworms, millipedes, dung beetles, fiddler crabs and sea cucumbers. Our examples show us that detritivores can be found in all environments and hold an important place in the food web as decomposers.

Question 8

Keystone species

Answer 8

A keystone species is an organism that helps define an entire ecosystem. Without its keystone species, the ecosystem would be dramatically different or cease to exist altogether. Keystone species have low functional redundancy.

Question 9

Trophic Cascade

Answer 9

Trophic cascades are powerful indirect interactions that can control entire ecosystems. Trophic cascades occur when predators limit the density and/or behavior of their prey and thereby enhance survival of the next lower trophic level.

Question 10

Describe differences between food web and trophic cascade diagrams

Answer 10

A food chain follows one path of energy and materials between species. A food web is more complex and is a whole system of connected food chains. In a food web, organisms are placed into different trophic levels. A trophic cascade occurs when one species has a change in population size, resulting in changes in populations of other species within the food chain.

Question 11

Identifying trophic levels of organisms in a food web

Answer 11

• 1st Trophic Level: Producer; Makes its own food
• 2nd Trophic Level: Primary Consumer; Consumes producers
• 3rd Trophic Level: Secondary Consumer; Consumes primary consumers
• 4th Trophic Level: Tertiary Consumer; Consumes secondary consumers