Biology Chapter 3 - The Biosphere

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Questions and Answers

What does the biosphere consist of?

Only the atmosphere

All life on Earth (correct)

Only land

Only water

What is ecology?

The scientific study of interactions among organisms and between organisms and their physical environment.

What is a species?

A group of similar organisms that can breed and produce fertile offspring.

What is a population?

A group of individuals that belong to the same species and live in the same area. Signup and view all the answers

What is a community?

An assemblage of different populations that live together in a defined area. Signup and view all the answers

What is an ecosystem?

All the organisms that live in a place together with their physical environment. Signup and view all the answers

What is a biome?

A group of ecosystems that share similar climates and typical organisms. Signup and view all the answers

What are biotic factors?

Biological influences on organisms. Signup and view all the answers

What are abiotic factors?

Any nonliving part of the environment. Signup and view all the answers

What methods are used in ecological studies?

Observation, experimentation, and modeling. Signup and view all the answers

What are primary producers?

The first producers of energy-rich compounds. Signup and view all the answers

What are autotrophs?

Organisms that capture energy from sunlight or chemicals. Signup and view all the answers

How do consumers obtain energy and nutrients?

They rely on other organisms for energy and nutrients. Signup and view all the answers

What are heterotrophs?

Organisms that must acquire energy from other organisms. Signup and view all the answers

What are carnivores?

Animals that kill and eat other animals. Signup and view all the answers

What are herbivores?

Animals that obtain energy and nutrients by eating plants. Signup and view all the answers

What are omnivores?

Animals that obtain energy from both plants and animals. Signup and view all the answers

What are scavengers?

Animals that consume carcasses of dead animals. Signup and view all the answers

What are decomposers?

Organisms that chemically break down organic matter. Signup and view all the answers

How does energy flow through ecosystems?

In a one-way stream, from primary producers to various consumers. Signup and view all the answers

What is a food chain?

A series of steps in which organisms transfer energy. Signup and view all the answers

What is a food web?

A complicated network of feeding interactions. Signup and view all the answers

What do ecological pyramids illustrate?

The relative amount of energy or matter at each trophic level. Signup and view all the answers

How does matter move through the biosphere?

Matter is recycled within and between ecosystems. Signup and view all the answers

What is nitrogen fixation?

A process where bacteria convert nitrogen gas into ammonia. Signup and view all the answers

What is denitrification?

A process where soil bacteria convert nitrates into nitrogen gas. Signup and view all the answers

What is limiting nutrient?

The nutrient whose supply limits productivity. Signup and view all the answers

Study Notes

Biosphere and Ecology

The biosphere includes all life on Earth and the environments where life exists (land, water, atmosphere).
Ecology is the scientific study of interactions among organisms and between organisms and their physical environment.

Biological Groups

A species is defined as a group of similar organisms that can interbreed and produce fertile offspring.
A population consists of individuals of the same species living in a specific area.
A community is an assembly of different populations living together in a defined area.
An ecosystem encompasses the organisms in a particular area along with their physical environment.
A biome is a collection of ecosystems that share similar climates and characteristic organisms.

Biotic and Abiotic Factors

Biotic factors refer to living components in an environment, such as animals, plants, and microorganisms.
Abiotic factors include nonliving elements like sunlight, temperature, water, and soil types.

Ecological Methods

Modern ecological studies utilize three methodologies: observation, experimentation, and modeling, guided by the scientific method.

Producers and Energy Acquisition

Primary producers generate energy-rich compounds for use by other organisms and are mainly autotrophs.
Autotrophs capture energy from sunlight or chemicals, transforming it into usable forms.
Photosynthesis is the process of converting sunlight into energy-rich carbohydrates, while chemosynthesis uses chemical energy to create carbohydrates.

Consumers and Their Types

Consumers, or heterotrophs, obtain energy by consuming other organisms.
Different types of consumers include:
- Carnivores: Animals that eat other animals (e.g., snakes, dogs).
- Herbivores: Animals that consume plant material (e.g., cows, deer).
- Omnivores: Organisms that eat both plants and animals (e.g., humans, bears).
- Scavengers: Animals that feed on dead organisms (e.g., vultures).
- Decomposers: Organisms that break down organic material (e.g., bacteria, fungi).
- Detritivores: Feed on detritus particles, assisting in decomposition (e.g., earthworms, snails).

Energy Flow in Ecosystems

Energy flows through ecosystems in a unidirectional manner, passing from primary producers to various consumers.
Food chains illustrate energy transfer through a sequence of feeding relationships.
Food webs represent complex networks of feeding interactions across multiple organisms.

Ecological Pyramids

Ecological pyramids display the distribution of energy, biomass, and the number of organisms at each trophic level.
A pyramid of energy indicates energy availability, a biomass pyramid shows the living organic matter, and a pyramid of numbers reflects individual organism counts.

Matter Cycles in the Biosphere

Unlike energy, matter within ecosystems is recycled.
Biogeochemical cycles depict movements of essential elements among organisms and the environment.

Nutrient Cycling

Water continuously cycles between oceans, the atmosphere, and land, infiltrating living organisms and nonliving environments.
Nutrients are vital chemical substances that organisms require for life processes.
Essential nutrient cycles involve carbon, nitrogen, and phosphorus, which are crucial for sustaining life.

Nutrient Fixation Processes

Nitrogen fixation involves bacteria converting nitrogen gas from the atmosphere into ammonia for use by living organisms.
Denitrification is the process where soil bacteria convert nitrates back into nitrogen gas, releasing it into the atmosphere.

Primary Productivity and Nutrient Limitation

An ecosystem's primary productivity may be constrained by nutrient availability, even when sunlight and water are abundant.
Limiting nutrients are the specific nutrients whose presence restricts productivity in ecosystems.

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Test your knowledge on the biosphere and ecology with these flashcards. Explore key terms and definitions related to life on Earth and the interactions within ecosystems. Perfect for students studying biology and environmental science.