Characteristics of Living Organisms

Flashcards based on the characteristics of living organisms for IGCSE Biology.

What acronym is used to remember the unifying characteristics of living organisms?

MRS C GREN (Movement, Respiration, Sensitivity, Control, Growth, Reproduction, Excretion, Nutrition)

What is the difference between autotrophic and heterotrophic organisms?

Autotrophic organisms produce their own food (e.g., plants), while heterotrophic organisms obtain food from other sources (e.g., animals).

What are the waste products of respiration in living organisms?

Carbon dioxide and water are the waste products of respiration.

What is excretion?

Excretion is the removal of toxic materials and waste products from organisms.

What is homeostasis?

Homeostasis is the process by which living organisms maintain internal stability in response to environmental changes.

What is the difference between sexual and asexual reproduction?

Sexual reproduction involves the fusion of male and female gametes, while asexual reproduction involves a single parent producing identical offspring.

What are the main features of prokaryotic organisms?

Prokaryotic organisms are single-celled, lack a nucleus, and have genetic material located in the cytoplasm.

What is a pathogen?

A pathogen is any microorganism that causes disease in another organism.

What distinguishes viruses from living organisms?

Viruses do not exhibit the eight life processes on their own and require a host cell to reproduce.

What is one method used by plants to respond to light?

Phototropism describes a plant's response to light, causing shoots to grow towards sunlight.

What is photosynthesis?

Photosynthesis is the process by which green plants and some organisms convert sunlight into chemical energy in the form of glucose.

What is chlorophyll?

Chlorophyll is the green pigment found in plants that is essential for photosynthesis.

What is cellular respiration?

Cellular respiration is the process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

What are the key reactants of photosynthesis?

The key reactants of photosynthesis are carbon dioxide and water.

What are the products of photosynthesis?

The products of photosynthesis are glucose and oxygen.

What role does sunlight play in photosynthesis?

Sunlight provides the energy needed for plants to perform photosynthesis.

What is the general equation for photosynthesis?

The general equation for photosynthesis is: $$6CO2 + 6H2O + light
ightarrow C6H{12}O6 + 6O2$$.

What is the purpose of photosynthesis?

The purpose of photosynthesis is to convert solar energy into chemical energy and provide food for the plant.

What is a producer in an ecological context?

A producer is an organism that creates its own food through photosynthesis, typically plants.

What are consumers in an ecological context?

Consumers are organisms that cannot produce their own food and rely on consuming other organisms.

What is a primary consumer?

A primary consumer is an organism that eats producers, usually herbivores.

What is a secondary consumer?

A secondary consumer is an organism that eats primary consumers, typically carnivores or omnivores.

What is a food chain?

A food chain is a linear sequence that shows how energy and nutrients flow from one organism to another.

What is a food web?

A food web is a complex network of food chains that illustrates how different organisms are interconnected.

What is an ecosystem?

An ecosystem is a community of living organisms interacting with each other and their physical environment.

What is biodiversity?

Biodiversity refers to the variety and variability of life forms within an ecosystem.

What is an autotroph?

An autotroph is an organism that produces its own food, mainly through photosynthesis or chemosynthesis.

What is a heterotroph?

A heterotroph is an organism that cannot produce its own food and must consume other organisms.

What is the significance of decomposers?

Decomposers break down dead organic matter and recycle nutrients back into the ecosystem.

What is nitrogen fixation?

Nitrogen fixation is the process by which nitrogen gas is converted into ammonia or related compounds in soil.

What is the carbon cycle?

The carbon cycle is the process through which carbon is exchanged between the atmosphere, oceans, soil, and living organisms.

What are greenhouse gases?

Greenhouse gases are gases that trap heat in the atmosphere and contribute to climate change.

What is climate change?

Climate change refers to significant changes in global temperatures and weather patterns over time.

What is a trophic level?

A trophic level is a position an organism occupies in a food chain, such as producer, primary consumer, or secondary consumer.

What is an energy pyramid?

An energy pyramid is a graphical representation showing the energy available at each trophic level in an ecosystem.

What is primary productivity?

Primary productivity is the rate at which energy is converted by photosynthetic and chemosynthetic autotrophs to organic substances.

What is a keystone species?

A keystone species is a species that has a disproportionately large effect on its ecosystem relative to its abundance.

What is habitat fragmentation?

Habitat fragmentation is the process where a large, continuous habitat is divided into smaller, isolated sections.

What is ecological succession?

Ecological succession is the process of change in species composition in a given area over time.

What is a climax community?

A climax community is a stable and mature ecological community that has reached a final stage of succession.

What are invasive species?

Invasive species are non-native organisms that spread rapidly in a new environment and can cause harm to native species.

What is conservation biology?

Conservation biology is the study focused on protecting

What is deciduous forest?

A deciduous forest is a type of forest characterized by trees that lose their leaves seasonally.

What is a biome?

A biome is a large geographic biotic unit, a major community of plants and animals with similar life forms and environmental conditions.

What is the difference between renewable and nonrenewable resources?

Renewable resources can be replenished naturally over time, while nonrenewable resources are finite and cannot be replaced once depleted.

What is sustainability?

Sustainability is the practice of using resources in a way that meets current needs without compromising the ability of future generations to meet theirs.

What is habitat loss?

Habitat loss is the destruction, degradation, or fragmentation of the natural environment that negatively affects species and ecosystems.

What is pollution?

Pollution is the introduction of harmful substances or contaminants into the environment, causing adverse effects.

What is an ecological footprint?

An ecological footprint is a measure of how much land and water area a human population requires to produce the resources it consumes and absorb its waste.

What is biomagnification?

Biomagnification is the process by which the concentration of toxic substances increases in the tissues of organisms at each successive trophic level.