Living Organisms in the Environment - Flashcards

Vocabulary flashcards covering ecological definitions, organism classification, soil science, energy flow, biotic interactions, nutrient cycling, and resource utilization.

Ecology

The study of the inter-relationships of living organisms with each other and with their environment.

Environment

The combination of biotic or abiotic factors that surround and act upon an organism.

Habitat

The place where a particular organism lives.

Species

A group of organisms with common ancestry that are capable of interbreeding to produce viable, fertile offspring.

Population

All the members of a particular species living together in a particular habitat, at a given point in time.

Community

All the populations of different species living together in a particular habitat, at a given point in time.

Ecosystem

A community of living organisms interacting with each other and with their abiotic environment.

Niche

The position or role of an organism within an ecosystem.

Microclimate

The localized conditions in a small space immediately surrounding an organism, such as under a log, leaf, or rock, which may differ from the general climate of the larger area.

Quadrat

A square frame of known area randomly placed within an ecosystem to count, measure abundance, and study distribution of slow-moving or stationary organisms in a uniform ecosystem.

Line Transect

A measuring tape or marked string placed in a straight line across an ecosystem to record organisms touching the line at regular intervals, used where there is a transition of organisms.

Taxonomic Hierarchy

The standard sequence of biological classification ranks: Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species.

Prokaryotes vs Eukaryotes Classification

Prokaryotes lack a nucleus (Bacteria Kingdom), whereas Eukaryotes possess a nucleus and are subdivided into Unicellular (Protist Kingdom) and Multicellular (Fungi, Animal, and Plant Kingdoms).

Vertebrates

Chordate animals possessing a backbone, categorized into Fish, Amphibians, Reptiles, Birds, and Mammals.

Invertebrates

Animals without a backbone, including groups such as Sponges, Cnidarians, Molluscs, Annelids, Arthropods, and Echinoderms.

Clay Soil

Soil composed of very small particles that pack closely together, retaining water by capillarity, draining slowly, and attracting $K^+$ and $Ca^{2+}$ ions to prevent leaching.

Sandy Soil

Soil with large, loosely packed particles that are well-aerated and drain rapidly, leading to low water-holding capacity and fast mineral leaching.

Loam Soil

A balanced mixture of sand and clay that retains sufficient water and mineral ions without becoming easily waterlogged, serving as an ideal medium for agriculture.

Humus

Dark, sticky material formed from the decomposition of organic matter (dead organisms, faeces) that binds soil particles into crumb structures, stores nitrogen, and feeds soil organisms.

Producer

Autotrophic organisms, most often photosynthetic like plants, algae, or cyanobacteria, that convert solar energy into chemical energy.

Primary Consumer

Organisms, usually herbivores, that feed directly on producers, algae, or bacteria.

Secondary Consumer

Carnivorous organisms that feed on primary consumers.

Tertiary Consumer

Carnivore-eating carnivores that consume secondary consumers, such as eagles or large fish.

Quaternary Consumer

Carnivores that feed on tertiary consumers in a food chain.

Apex Consumer

An organism located at the very top of a food chain.

Ecological Pyramid of Energy

A quantitative model illustrating energy stored as biomass at each trophic level, decreasing from Primary Producers ($20{,}000\,\text{kcal/m}^2/\text{yr}$) up to Quaternary Consumers ($2\,\text{kcal/m}^2/\text{yr}$).

Mutualism

A symbiotic relationship where both species benefit significantly and often rely on each other to survive, such as Rhizobium bacteria in leguminous plant root nodules.

Ectoparasite vs Endoparasite

An ectoparasite lives on the exterior of its host, whereas an endoparasite resides inside the body of its host.

Commensalism

A relationship in which one organism benefits while the other is unharmed and not heavily dependent on the interaction.

Decomposers

Fungi and bacteria that break down complex organic substances from waste and dead matter into simpler, reusable nutrients.

Carbon Cycle

The movement of carbon through the biosphere, where atmospheric $\text{CO}_2$ ($0.03\%$) is fixed by photosynthesis and released by plant, animal, and root respiration, decay, and fossil fuel combustion.

Nitrogen Cycle

The process by which atmospheric nitrogen ($79\%$) is converted by nitrogen-fixing bacteria into ammonia ($\text{NH}_3$) and nitrifying bacteria into nitrates ($\text{NO}_3^-$) for plant use, before being returned to the air by denitrifying bacteria.

Rhizobium

Symbiotic bacteria residing in the roots of leguminous plants that possess the ability to fix atmospheric nitrogen into a soluble form.

Habitat Classification

Habitats categorized into Terrestrial (comprising Arboreal and Edaphic) and Aquatic (comprising Freshwater and Marine).

Manufactured Materials

Products made from natural sources: Paper (wood pulp), Glass (soda ash, silica, sand, lime), Metals (iron, gold, tin, aluminium), and Plastics (petroleum).