Unit 8: Ecology

What is a biogeochemical cycle?

A biogeochemical cycle is a closed loop through which a chemical element or water moves through ecosystems.

What is a biome? Give an example.

A biome is a large community of plants and animals that live in the same place. Ex: swamp

What is a community?

A community is all of the populations of different species that live in the same area and interact with one another. A community is composed of all of the biotic factors of an area.

What is a biome?

A large community of plants and animals distinguished by the dominant forms of animal and plant life and the climate.

What is a niche?

A niche is a role a species plays in the ecosystem. In other words, a niche is how an organism makes a living.

Compare and contrast the ecosystem concepts of niche and habitat.

A niche refers to the role of a species in its ecosystem. A habitat is a physical environment in which a species lives and to which it is adapted.

What is a population?

A population is a group of organisms belonging to the same species that live in the same area and interact with one another.

What is a species?

A species is a group of individuals that are genetically related and can breed to produce fertile young. Individuals are not members of the same species if their members cannot produce offspring that can also have children.

Identify and define two processes by which water changes state in the water cycle.

Evaporation - liquid water is turned into water vapor. Condensation - water vapor is turned into liquid water.

What is the carbon cycle?

Interconnected pathways through which carbon is recycled through the biotic and abiotic components of the biosphere.

Name three factors that can be used to describe a habitat.

The average amount of sunlight received each day, the range of annual temperatures, and average yearly rainfall can all describe a habitat.

What is genetic diversity?

The differences among individuals or populations; variation within a species.

What is species diversity?

The number of different species in a particular ecosystem or on Earth.

What is a habitat?

The physical environment in which a species lives and to which it has become adapted.

What is nitrogen fixation?

The process of changing nitrogen gas to nitrates.

Can two species share the same niche? Why or why not?

A species niche must be specific to that species; no two species can fill the same niche. They can have very similar niches, which can overlap, but there must be distinct differences between any two niches. If two species do fill the same niche, they will compete for all necessary resources. One species will outcompete the other, forcing the other species to adapt or risk extinction. This is known as competitive exclusion.

In a forest, what are five biotic factors present? Five abiotic factors?

Abiotic factors - sunlight, climate, soil, water, and air. Biotic factors - plants, animals, their remains, bacteria and fungi.

What is an abiotic factor?

An aspect of the environment that is not a living organism, such as soil, water or air.

What is an ecosystem?

An ecosystem includes the living organisms (all the populations) in an area and the non-living aspects of the environment.

How do ecologists define the term ecosystem? What makes up an ecosystem?

An ecosystem is a unit of nature and the focus of study in ecology. It consists of all the biotic and abiotic factors in an area and their interactions.

How have human activities increased atmospheric carbon dioxide levels?

Because of human activities, there is more carbon dioxide in the atmosphere today than in the past hundreds of thousands of years. This is leading to increased greenhouse gases and global climate change.

What is biodiversity?

Biodiversity refers to the variety of life and its processes, including the variety of living organisms, the genetic differences among them, and the communities and ecosystems in which they occur.

What is a biotic factor?

Components of the environment that are living, or were alive and then died, such as plants or animals.

What do ecologists study?

Ecologists can study the biomes, organisms that live in different biomes, or study if a biome is stable.

What is meant by ecosystem diversity?

Ecosystem diversity describes the many types of functional units formed by living communities interacting with their environments.

Describe a major method by which carbon is cycled.

Living organisms release carbon dioxide as a byproduct of cellular respiration.

What is the biosphere?

Part of the planet and atmosphere with living organisms.

What are the three measures of life's variations?

Species diversity, genetic diversity, and ecosystem diversity

What is the study of ecology?

Study of how living organisms interact with each other and with their environment.

Why can't plants use nitrogen gas directly?

The two nitrogen atoms in a molecule of nitrogen gas are held together by a very stable triple bond. This bond must be broken for the nitrogen to be used. The nitrogen gas must be changed to a form called nitrates, which plants can absorb through their roots.

Why is cycling carbon important?

This carbon must be cycled - removed from the atmosphere - back into living organisms, or it stays in the atmosphere. Increased carbon in the atmosphere contributes to the greenhouse effect on Earth.

State the competitive exclusion principle.

Two different species cannot occupy the same niche in the same place for very long.

What is ammonification?

When plants and other organisms die, decomposers break down their remains. In the process, they release nitrogen in the form of ammonium ions.