Year 11 Biology – Semester 1 Revision

Vocabulary flashcards covering key biological concepts, classifications, ecological principles, environmental issues, and conservation strategies from the Year 11 Biology lecture notes.

Scientific Method

A systematic process of observation, measurement, experimentation, and hypothesis testing used to develop biological knowledge.

Independent Variable

The factor deliberately changed or manipulated in an experiment to test its effect.

Dependent Variable

The factor measured in an experiment; it responds to changes in the independent variable.

Controlled Variable

Any factor kept constant to ensure that observed effects are due only to the independent variable.

Population Sampling

Techniques used to estimate population characteristics by studying a subset of individuals.

Transect

A straight-line sampling method where organisms are recorded along a predetermined path.

Quadrat

A square frame used to isolate and study a standard unit of area for population estimates.

Population Density

The number of individuals per unit area or volume in a habitat.

Population Size

The total number of individuals in a defined population.

Biodiversity

The variety of life on Earth, encompassing genetic, species, and ecosystem diversity.

Genetic Diversity

Variation of genes within a species, providing raw material for evolution.

Species Diversity

The number and relative abundance of species in a community.

Ecosystem Diversity

The range of different habitats, biological communities, and ecological processes.

Natural Selection

The process whereby individuals with advantageous heritable traits survive and reproduce more successfully.

Stabilizing Selection

Natural selection that favors intermediate phenotypes and reduces variation.

Directional Selection

Natural selection that favors one extreme phenotype, shifting a population’s trait distribution.

Disruptive Selection

Natural selection that favors both extreme phenotypes over intermediate forms.

Levels of Classification

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species—hierarchical taxonomic ranks.

Morphological Species Concept

Defines species by physical characteristics and structural features.

Biological Species Concept

Defines species as groups of interbreeding natural populations reproductively isolated from others.

Phylogenetic Species Concept

Defines species based on evolutionary history and genetic distinctiveness.

Phylum Chordata

Animals possessing a notochord at some life stage; includes fish, amphibians, reptiles, birds, and mammals.

Fish

Aquatic, gill-breathing, ectothermic vertebrates with fins.

Amphibia

Moist-skinned vertebrates that typically metamorphose from aquatic larvae to terrestrial adults.

Reptilia

Ectothermic vertebrates with scales, laying shelled eggs on land.

Aves

Endothermic, feathered vertebrates adapted for flight; birds.

Mammals

Endothermic vertebrates with hair and mammary glands that produce milk.

Kingdom Plantae

Multicellular, photosynthetic eukaryotes including mosses, ferns, conifers, and flowering plants.

Mosses (Bryophytes)

Non-vascular plants reproducing via spores, lacking true roots.

Ferns (Pteridophytes)

Seedless vascular plants with fronds and spores produced on leaf undersides.

Conifers (Gymnosperms)

Seed plants with cones and needle-like leaves; mostly evergreen.

Flowering Plants (Angiosperms)

Seed plants producing flowers and fruit; the most diverse plant group.

Monocots

Angiosperms with one cotyledon, parallel veins, and fibrous roots.

Dicots

Angiosperms with two cotyledons, net-like veins, and taproots.

Phylogenetics

The study of evolutionary relationships among organisms using genetic and morphological data.

Cladogram

A branching diagram showing inferred evolutionary relationships based on shared traits.

Intraspecific Competition

Competition among individuals of the same species for resources.

Interspecific Competition

Competition between different species for shared resources.

Symbiosis

Close, long-term biological interaction between two different species.

Mutualism

Symbiotic relationship in which both species benefit.

Commensalism

Symbiotic relationship in which one species benefits and the other is unaffected.

Parasitism

Symbiotic relationship where one organism benefits at the expense of the host.

Predator-Prey Relationship

Interaction where one organism (predator) consumes another (prey), influencing population dynamics.

Food Chain

Linear sequence of organisms through which energy and nutrients pass as one eats another.

Food Web

Interconnected food chains showing all feeding relationships in an ecosystem.

Ecological Pyramid

Graphical representation of trophic level information such as numbers, biomass, or energy.

Pyramid of Numbers

Ecological pyramid displaying the count of organisms at each trophic level.

Pyramid of Biomass

Ecological pyramid showing total mass of living matter at each trophic level.

Pyramid of Energy

Ecological pyramid illustrating energy flow and loss between trophic levels.

Nitrogen Cycle

Biogeochemical cycle involving nitrogen fixation, nitrification, assimilation, ammonification, and denitrification.

Carbon Cycle

Movement of carbon among biosphere, geosphere, hydrosphere, and atmosphere via processes like photosynthesis and respiration.

Fundamental Niche

Full range of environmental conditions under which a species can survive and reproduce.

Realised Niche

Actual niche a species occupies, limited by competition and other biotic factors.

Competitive Exclusion Principle

No two species can occupy the same niche indefinitely when resources are limiting.

r-Selected Species

Organisms that reproduce quickly, produce many offspring, and thrive in unstable environments.

K-Selected Species

Organisms that produce few offspring with high parental care, adapted to stable environments.

Capture–Mark–Recapture

Population size estimation method involving capturing, marking, releasing, and recapturing individuals.

Population Growth Curve

Graph showing change in population size over time through lag, exponential, transitional, and plateau phases.

Lag Phase

Initial slow growth period while organisms acclimate to a new environment.

Exponential Phase

Period of rapid, accelerating population growth with abundant resources.

Transitional Phase

Growth rate slows as resources become limited and competition increases.

Plateau (Stationary) Phase

Population size stabilizes as birth rates equal death rates.

Density-Independent Factor

Environmental factor affecting populations regardless of density (e.g., weather events).

Density-Dependent Factor

Environmental factor whose effects increase with population density (e.g., disease, competition).

Primary Succession

Community development on barren substrate lacking soil, such as after volcanic lava.

Secondary Succession

Community recovery after disturbance where soil remains, such as post-fire regrowth.

Invasive Species

Non-native organisms that spread rapidly and harm ecosystems, economies, or health.

Biological Control

Use of natural predators, parasites, or pathogens to manage pest populations.

Chemical Control

Use of pesticides or herbicides to reduce unwanted species.

Eutrophication

Nutrient enrichment of water bodies leading to algal blooms, oxygen depletion, and fauna loss.

Dryland Salinity

Accumulation of salts in soil surface layers due to vegetation clearing and rising water tables.

Biomagnification

Increase in pollutant concentration as it moves up food chains.

Bioaccumulation

Build-up of substances within an organism over time.

Climate Change

Long-term alteration of temperature and typical weather patterns on Earth.

Global Warming

Recent increase in Earth’s average surface temperature due to rising greenhouse gases.

Conservation (Environmental Approach)

Protecting habitats and ecosystems to preserve biodiversity.

Conservation (Genetic Approach)

Maintaining or enhancing genetic variation within and between populations.

Conservation (Management Approach)

Applying laws, policies, and sustainable practices to protect species and ecosystems.

Dichotomous Key

Tool using paired, contrasting statements to identify organisms based on characteristics.

Incubation Temperature (Turtles)

Environmental temperature influencing turtle egg development and hatching success rates.