ENVRIONMENTAL BIO 2.1 ECOSYSTEM & NUTRIENT CYCLING

What is ecology?

the study of how species interact with the biotic (living) and abiotic (nonliving) components of their environments

Habitat

the physical environment where an organism lives

biotic

components are all living parts

abiotic

components are all nonliving parts like air, water, and soil

What are the hierarchical levels of organization in ecology?

Individual → Population → Community → Ecosystem → Biome → Biosphere.

Population

all individuals of one species in an area

Community

all populations of different species interacting in an area

Ecosystem

all living and nonliving factors interacting in an area

Biome

type of ecosystem defined by climate and vegetation.
Biosphere: total area on Earth where life exists.

What is energy flow vs. matter cycling?

Energy flows one way through ecosystems and must be continuously supplied; matter cycles repeatedly through ecosystem processes.

Name the major cycles in ecosystems.

Carbon cycle, nitrogen cycle, phosphorus cycle, and water cycle.

What are sinks in cycles

abiotic or biotic components where nutrients are stored during cycling

What two abiotic factors mainly define terrestrial biomes?

Mean annual temperature and mean annual precipitation.

What are anthromes?

human-altered biomes, including cities, villages, croplands, rangelands, and forestlands

Limiting factor

a resource that controls population size.

Range of tolerance

the range of a factor a species can survive and reproduce within.

What is photosynthesis?

A chemical reaction carried out by producers using sunlight, CO₂, and water to make sugar and oxygen

What is cellular respiration?

A process in which organisms break down sugar using oxygen to release energy and produce CO₂ as waste

Producers

make energy-rich molecules using sunlight (photosynthesis);

consumers

eat other organisms for energy.

How do humans disrupt the carbon cycle?

By burning fossil fuels, causing deforestation, and setting forest fires, which increase atmospheric CO₂.

Nitrogen fixation

bacteria convert atmospheric nitrogen (N₂) to usable forms (NH₃).

Nitrification

bacteria convert ammonia (NH₃) to nitrates (NO₃)

Denitrification

bacteria convert nitrates back to nitrogen gas (N₂)

How do humans disrupt the nitrogen cycle?

By fertilizing crops and burning fossil fuels, increasing nitrogen availability in ecosystems

What is the phosphorus cycle?

describes the movement of phosphorus from rocks to soil and water, then to organisms, and back, without a gaseous phase.

How do humans disrupt the phosphorus cycle

Through open-pit mining and the use of fertilizers and animal waste.

Why is understanding nutrient cycling important?

To maintain ecosystem resilience and adapt to environmental changes, especially with climate change