BIO1022 Test 1 — Key Terms & Concepts Glossary Flashcards

A complete set of vocabulary flashcards covering key terms and concepts across Weeks 1 to 6 for BIO1022 Test 1 preparation.

Natural selection

The process by which favourable heritable traits become more common in a population because individuals with those traits survive and reproduce more successfully.

Requirements for natural selection

Overproduction of offspring, heritable variation, and differential survival and reproduction; it does not require human intervention.

Artificial selection

Selection of traits by humans for their own goals, rather than by environmental pressures.

Sexual selection

A form of natural selection where the selective agent is the opposite sex, favouring traits that increase mating success (even if they reduce survival).

Biological species concept

Defines a species as a group of populations whose members can interbreed and produce viable, fertile offspring.

Limitation of the biological species concept

It cannot be applied to asexual organisms or to fossils, since interbreeding cannot be observed in either case.

Morphological species concept

Defines species based on physical/body-plan characteristics; useful for fossils and asexual organisms.

Phylogenetic species concept

An alternative species concept (along with ecological and morphological concepts) used when interbreeding cannot be assessed.

Reproductive isolation

Biological barriers that prevent members of different species from interbreeding and producing fertile offspring; essential for speciation because it blocks gene flow.

Prezygotic isolation

Barriers that prevent mating or fertilization from occurring at all, e.g. habitat, behavioural, temporal, mechanical, and gametic isolation.

Postzygotic isolation

Barriers that act after fertilization, preventing a hybrid from developing, surviving, or reproducing, e.g. hybrid unviability, hybrid sterility, hybrid breakdown.

Habitat isolation

A prezygotic barrier where species live in different habitats and rarely encounter each other.

Speciation

The formation of new species, typically driven by reproductive isolation combined with natural selection or genetic divergence.

Allopatric speciation

Speciation that occurs when a population is divided by a geographic barrier.

Sympatric speciation

Speciation that occurs within the same geographic area, without a physical barrier separating populations.

Phylogenetic tree

A diagram representing a hypothesis of the evolutionary relationships among organisms, with branch points showing divergence from a common ancestor.

Shared derived character

A trait that originated in a common ancestor and is shared only by a subgroup of its descendants; used to build phylogenetic trees.

Shared ancestral character

A trait present in a common ancestor and broadly shared across a group, so it is not useful for resolving relationships within that group.

Fossil

A preserved physical record of an extinct organism, providing evidence of past anatomical features and a timeline for when traits appeared.

Fossils vs. phylogeny

Both provide independent evidence for evolution: fossils give the "when" (timeline and physical evidence), phylogeny gives the "how" (hypothesised relationships, often from genetic data).

Three lines of evidence for human–ape relatedness

Anatomical evidence, genetic evidence, and fossil evidence.

Out of Africa hypothesis

The theory that modern humans originated in Africa and later migrated to colonise the rest of the world, supported by the oldest/most diverse hominid fossils and by genetic diversity patterns being found in Africa.

Serial founder effect

The pattern where genetic diversity decreases with distance from Africa because each new founding population carries only a subset of the previous group's diversity, indicating recent, rapid global colonisation.

Obligate bipedalism

Walking upright on two legs as the primary and required form of locomotion; a distinctive human trait.

Australopithecus

An early hominid genus whose fossil record provides key evidence for the early evolution of bipedalism.

Encephalization (large brain)

A large brain relative to body size, a distinct feature of the human lineage linked to complex thought, language, and culture.

Culture

The cumulative, complex transmission of shared knowledge, beliefs, and practices across generations through learning rather than genetics; considered a potentially unique human characteristic.

Consciousness

Awareness of one's own existence and surroundings, argued to be uniquely well-developed in humans, enabling abstract thought and symbolic communication.

Body plan classification criteria

Animals are classified phylogenetically based on symmetry, number of tissue/germ layers, and presence/absence of a body cavity (coelom).

Diploblastic

Having two germ layers (ectoderm and endoderm); typical of basal animal phyla like Cnidaria.

Triploblastic

Having three germ layers (ectoderm, mesoderm, endoderm); the mesoderm allows development of complex organs and a coelom, seen in Bilaterians.

Radial symmetry

Body parts arranged around a central axis, typical of basal/simple animal phyla such as Cnidaria; suits a sessile or slow-moving lifestyle.

Bilateral symmetry

Body organized with left and right mirror-image halves; a defining feature of Bilaterians, associated with directional movement.

Bilaterians

Animals with bilateral symmetry and three germ layers, whose developmental complexity underlies their tremendous diversity.

Coelom

A fluid-filled body cavity completely lined by tissue derived from the mesoderm; allows independent organ movement and complex organ systems.

Chordata

The animal phylum defined by four shared features: notochord, dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail (at some life stage).

Notochord

A flexible rod providing skeletal support in chordates; replaced by the vertebral column in vertebrates.

Dorsal hollow nerve cord

A chordate feature that develops into the central nervous system (brain and spinal cord).

Jaws (evolutionary innovation)

A key chordate innovation that enabled active predation and exploitation of new food sources.

Tetrapods

Four-limbed vertebrates; the evolution of limbs from fins enabled the transition from water to land.

Amniote egg

A self-contained, waterproof egg that allowed vertebrates to reproduce independently of water, enabling full colonisation of land.

Hydrostatic skeleton

A skeleton formed by fluid held under pressure in a closed body compartment; flexible but unable to support large terrestrial body size (e.g. earthworm).

Exoskeleton

A hard skeleton on the outside of the body providing protection and support, but must be shed (moulted) for growth (e.g. lobster, insects).

Endoskeleton

An internal, rigid skeletal framework providing support and organ protection, allowing continuous growth without shedding (e.g. vertebrates).

Respiration by diffusion

Gas exchange directly across the body surface; only effective in small, thin-bodied animals (e.g. flatworms).

Gills

Respiratory organs with high surface area specialised for extracting oxygen from water; ineffective/collapse in air.

Lungs

Internal respiratory organs adapted for gas exchange with air in terrestrial animals.

Open circulatory system

A system where blood/hemolymph is pumped into a body cavity and directly bathes the organs, rather than staying within vessels.

Closed circulatory system

A system where blood remains contained within vessels at all times; more efficient, suited to larger, more active animals.

Circulatory system components

Heart (pump), blood vessels (arteries, veins, capillaries), and blood, which transport gases, nutrients, hormones, and waste.

Pulmonary artery

Carries oxygen-poor blood from the right ventricle to the lungs.

Pulmonary vein

Carries oxygen-rich blood from the lungs to the left atrium.

Aorta

Carries oxygen-rich blood from the left ventricle to the rest of the body.

Vena cava

Carries oxygen-poor blood from the body back to the right atrium.

Universal nutritional needs

Despite different environments, all organisms need the same basic nutrients — carbohydrates, lipids, proteins, vitamins, and minerals — for energy and building tissue.

Mechanical digestion

Physical breakdown of food into smaller pieces (e.g. chewing, churning) to increase surface area for enzymes.

Chemical digestion

Enzyme-driven breakdown of food macromolecules into absorbable subunits (e.g. amylase breaking down carbohydrates, pepsin breaking down proteins).

Carnivore digestive adaptations

Sharp teeth for tearing meat and a relatively short digestive tract, since meat is highly digestible.

Herbivore digestive adaptations

Flat grinding molars, a long digestive tract, and often a cecum/rumen containing symbiotic microorganisms to digest cellulose.

Omnivore digestive adaptations

A generalized, medium-length digestive tract combining features of both carnivores and herbivores.

Cellulase

An enzyme produced by symbiotic gut bacteria (not by the herbivore itself) that breaks down cellulose into digestible sugars.

Large intestine function

Reabsorbs water from undigested material and compacts waste before excretion.

Excretion

Removal of metabolic waste products (e.g. urea) from the body via the excretory system (e.g. kidneys), distinct from defecation.

Defecation

Elimination of undigested food and waste from the digestive tract as faeces.

Satiety

The feeling of fullness after eating; enhanced by high-fibre and high-protein foods, which slow gastric emptying and stimulate satiety hormones.

Asexual reproduction

Reproduction from a single parent (e.g. budding, fragmentation) producing genetically identical offspring; no genetic diversity is generated.

Sexual reproduction

Reproduction involving fusion of gametes from two parents, generating genetically diverse offspring.

Internal fertilization

Fusion of sperm and egg inside the female's body.

External fertilization

Fusion of sperm and egg outside the body, typically in water.

Hermaphrodite

An organism possessing both male and female reproductive organs; some can self-fertilize, others must mate.

Genetic sex determination

Sex determined by chromosomes/genetic factors, activating a hormonal cascade that directs reproductive development.

Environmental sex determination

Sex determined by environmental factors such as temperature (e.g. in some reptiles), rather than by chromosomes.

Hormones (in development)

Chemical messengers (e.g. testosterone, estrogen) that regulate growth, maturation, and the differentiation of reproductive organs and secondary sexual characteristics.

Conservation risk of environmentally-sensitive development

Environmental shifts (e.g. climate change) can skew sex ratios, threatening a population's ability to reproduce and survive.