KEY! Biology Semester 2 Final Exam Review

1. The difference between primary and secondary succession can be explained using which of the following sets of terms: Pioneer species, lichen, climax community, soil, grasses and small shrubs?

• Primary succession begins with pioneer species like lichen on bare rock, forming soil, followed by grasses and small shrubs, leading to a climax community; secondary succession starts with existing soil and faster growth of grasses and shrubs.

• Primary succession starts with existing soil and grasses, while secondary succession begins with lichen and pioneer species on bare rock.

• Both primary and secondary succession start with climax communities and end with pioneer species like lichen.

• Primary succession and secondary succession both begin with grasses and small shrubs, without the involvement of lichen or soil formation.

What is the most likely cause of a harmful algal bloom in a freshwater lake?

• Increased levels of oxygen from aquatic plants

• Excess nutrients like nitrogen and phosphorus from fertilizers

• Decreased sunlight reaching the lake surface

• Introduction of invasive fish species

Harmful algal blooms can affect aquatic ecosystems and human health in several ways. Which of the following are specific impacts of harmful algal blooms?

• They deplete oxygen in water and produce toxins harmful to humans.

• They increase fish populations and improve water quality.

• They reduce sunlight penetration and promote healthy aquatic plants.

• They have no effect on aquatic life or human health.

Which process in the nitrogen cycle is carried out by bacteria and converts atmospheric nitrogen (N₂) into a form usable by plants?

• Nitrification

• Denitrification

• Nitrogen fixation

• Ammonification

Which process removes carbon dioxide from the atmosphere?

• Combustion

• Photosynthesis

• Respiration

• Decomposition

What human activity most often leads to excess nitrogen in ecosystems, potentially causing algal blooms?

• Urban development

• Use of nitrogen-based fertilizers

• Hunting wildlife

• Planting trees

In a food chain, which organisms have the most available energy?

• Tertiary consumers

• Primary consumers

• Producers

• Secondary consumers

What happens to the energy that is not passed on to the next trophic level?

• It is destroyed

• It is converted into sunlight

• It is stored permanently

• It is lost as heat

The arrows in a food chain or food web show the direction of flow.

• energy

• water

• carbon dioxide

• nutrients

Which of the following are examples of producers?

• Algae

• Grass

• Mushroom

• Oak Tree

• Wolf