Edexcel (A) Biology A-level: Topic 5 - On the Wild Side

A set of flashcards summarizing key vocabulary and definitions from the lecture notes on ecosystems, succession, photosynthesis, climate change, and evolution.

Ecosystem

All the organisms living in a particular area, known as the community, as well as all the nonliving elements of that environment.

Community

All of the populations of organisms living in a particular habitat at a certain time.

Population

All of the organisms of a particular species living in a particular habitat at a certain time.

Habitat

The place where an organism lives.

Ecological niche

The specific role of a species within its habitat, including its interactions with biotic and abiotic factors.

Primary succession

The colonization of an area that was previously devoid of life, such as after a volcanic eruption.

Secondary succession

The re-colonization of an area that already has soil but has lost its vegetation, such as after a forest fire.

Pioneer species

Species that are the first to colonize previously disrupted or damaged ecosystems.

Decomposition

The process through which microorganisms break down dead organic matter, adding humus to the soil.

Climax community

The most productive, self-sustaining, and stable community of organisms that an environment can support.

Photosynthesis

The process by which green plants use sunlight to synthesize foods with the help of chlorophyll.

Light-dependent reactions

Part of photosynthesis where light energy is absorbed and converted into chemical energy in the form of ATP and NADPH.

Calvin cycle

The light-independent reactions of photosynthesis that convert carbon dioxide into glucose using ATP and NADPH.

Net primary productivity (NPP)

The rate at which energy is converted by photosynthesis into organic substances minus the energy used for respiration.

Gross primary productivity (GPP)

The total energy captured by photosynthesis before any is used for respiration.

Global warming

The gradual increase in the average temperature of the Earth's atmosphere and surface.

Greenhouse effect

The process by which certain gases trap heat in the Earth's atmosphere, contributing to global warming.

Natural selection

The process in which organisms better adapted to their environment tend to survive and produce more offspring.

Speciation

The formation of new and distinct species in the course of evolution.

What are the two essential components that constitute an ecosystem?

An ecosystem consists of all the organisms living in a particular area (community) and all the nonliving elements of that environment.

What is the primary distinction between primary and secondary succession?

Primary succession is the colonization of an area previously devoid of life (e.g., bare rock), whereas secondary succession is the re-colonization of an area that already has soil but lost its vegetation (e.g., after a fire).

What two main phases comprise the process of photosynthesis?

Photosynthesis is divided into Light-dependent reactions, where light energy is converted to chemical energy, and the Calvin cycle (light-independent reactions), which converts carbon dioxide into glucose.

Define Net Primary Productivity (NPP) and Gross Primary Productivity (GPP) and how they relate.

Gross Primary Productivity (GPP) is the total energy captured by photosynthesis. Net Primary Productivity (NPP) is GPP minus the energy used by producers for respiration.

How does the 'Greenhouse effect' contribute to 'Global warming'?

The Greenhouse effect is the natural process where certain atmospheric gases trap heat, warming the Earth. An enhanced Greenhouse effect, due to increased concentrations of these gases, leads to Global warming by trapping excessive heat.