3.3 Study Guide Flashcards
What are trophic levels?
Trophic levels are hierarchial levels in an ecosystem that contain species that share certain characteristics. The common trophic levels are producers, primary consumers, secondary consumers, tertiary consumers, and quaternary consumers.
What is an autotroph vs. a heterotroph?
An autotroph is an organism that can produce its own food for energy. This is usually done by plants through the process of photosynthesis.
A heterotroph is an organism that cannot produce its own food and therefore must consume other organisms to gain energy. This includes organisms like lions, giraffes, dolphins, dogs, ducks, etc.
What is a herbivore vs. an omnivore vs. a carnivore vs. a detritivore?
A herbivore is an organism that only eats plants. A carnivore is an organism that only eats other animals and consumes their flesh. An omnivore is an organism that eats both plants and animals. A detritivore eats dead organisms, decay, and remnants of organisms.
What is the difference between food web and trophic cascade diagrams?
A food web diagram shows how energy transfers from one organism to the next, while cascade diagrams show how organisms affect one another. The arrows in a food web represent energy transfer, while the arrows in a trophic cascade diagram represent direct and indirect effects. Trophic diagrams also show whether one species negatively or positively affects another. Food webs show what trophic levels each species is in.
In a food web, a species of grass is at the bottom. This grass is eaten by a species of grass hopper and a species of ant. The mouse is eaten by a rattlesnake, which is eaten by a hawk. The ants are eaten by a mantid, which is eaten by an owl. Identify the trophic levels of the organisms.
The grass species is the producer of the community. The grasshoppers and the ants are primary consumers. The mantid and the mouse are secondary consumers. The rattlesnake and the owl are tertiary consumers, and the hawk is a quaternary consumer.
In a trophic cascade model, a fox directly and negatively affects a sea bird species. The sea bird species directly and positively affects the soil nutrients, which directly and positivley affects the grass. Make a prediction as to how the fox affects the grass.
The fox negatively and indirectly affects the grass. This is because an increase of foxes will lead to fewer sea birds. With fewer sea birds, there will be less droppings to create more nutrient soil. Without nutrient soil, the grass will not grow well. This shows that an increase in the wolf population leads to a decline in the grass population.
