Biology: Effects of the Environment on Organisms and the Theory of Evolution

A comprehensive set of vocabulary flashcards covering environmental selection pressures, adaptations, theory of evolution, speciation, and evidence for evolution based on the lecture transcript.

Selection Pressures

Factors that affect an organism’s ability to survive and determine the population of a species by ‘selecting against’ individuals that are not suited to the environment.

Positive Selection Pressures

Factors that increase the chances of survival for an organism within an ecosystem.

Negative Selection Pressures

Factors that decrease the chances of survival for an organism within an ecosystem.

Biotic Factors

Factors relating to living organisms, such as competing species, predators, or members of the same species.

Abiotic Factors

Non-living environmental factors such as temperature, soil composition, $pH$, and sunlight.

Dormancy

A state in cold climates where growth and development are put on hold to conserve energy.

Osmoregulation

The process by which organisms manage their internal salt and water balance.

Sickle Cell Disease

A condition caused by a mutation in the haemoglobin gene that makes red blood cells misshapen and provides a survival advantage against malaria.

Biological Control

The use of a natural organism to limit the propagation and spread of an invasive species.

Bufotoxin

A toxin produced by cane toads throughout all stages of their life cycle that is lethal to most native Australian predators.

Carrying Capacity

The maximum population that a species’ environment and surrounding resources can support.

Red-bellied black snakes

A species that has developed structural and behavioural adaptations, such as smaller heads, to survive the introduction of cane toads.

Spatial Sorting

A process that favors individuals with traits that increase dispersal ability, such as longer legs, leading to faster movement at an invasion front.

Cactoblastis moth

A biological control agent whose larvae consumed large masses of prickly pear to control its population explosion in Australia.

Structural Adaptations

Physical features of an organism’s body, such as shape or size, that enhance its survival and reproduction.

Thermoregulation

The internal regulation of an organism's body temperature.

Xerophytes

Desert plants that possess structural adaptations to ensure adequate water balance for photosynthesis.

Stomatal pits

Invaginations in leaves that contain multiple stomata to trap moisture and create a humid microenvironment.

Physiological Adaptations

Functional or chemical changes within an organism's body, such as toxin production or metabolism changes, that aid survival.

Crassulacean acid metabolism (CAM)

A physiological adaptation where plants open stomata at night to reduce water loss, storing $CO_2$ as malic acid in vacuoles.

Countercurrent heat exchange

A physiological process where warm arterial blood transfers heat to cooler venous blood to regulate temperature.

Vasoconstriction

The narrowing of blood vessels to reduce blood flow and minimize heat loss.

Behavioural Adaptations

Specific actions or behaviors developed by animals, such as huddling or migrating, to increase survival chances.

Pneumatophores

A structural adaptation in Grey Mangroves consisting of a root system designed to obtain oxygen at high tide.

Chromatophores

Special cells in the blue-ringed octopus that change colour to warn off potential predators.

Natural Selection

The process where environmental conditions favor specific characteristics, leading to the survival of the fittest and passing of traits to offspring.

On the Origin of Species

The foundational book of evolutionary biology published by Charles Darwin in 1859.

Warbler-finch

The smallest Galapagos finch, characterized by a narrow, pointed beak adapted for catching insects.

Analogous Structures

Similar structures that arise in different species through convergent evolution because they face similar selection pressures.

Homologous Structures

Structures that appear different but have evolved from a common ancestor, such as the pentadactyl limb in vertebrates.

Biological Diversity

The variety of all forms of life on Earth, including diversity within characteristics and ecosystems.

Endosymbiotic Theory

The theory suggesting eukaryotic cells developed when larger cells consumed smaller cells, resulting in membrane-bound organelles.

Microevolution

Small-scale genetic changes within a species or population driven by mutation or selection over a short period.

Macroevolution

Evolutionary changes in whole groups of species over long periods that result in the origin of new species.

Allopatric Speciation

The formation of a new species when a population becomes divided by a geographical barrier.

Sympatric Speciation

The evolution of a new species within the same geographic area as the original population without physical separation.

Eohippus

An ancestral horse species from over $50$ million years ago that was the size of a small dog and lived in rainforests.

Merychippus

An intermediate horse ancestor from $15$ million years ago with teeth completely covered by enamel and three-toed feet.

Monotrematum sudamericanum

An early platypus ancestor from the Palaeocene era that was nearly double the size of the modern platypus.

Convergent Evolution

Process where unrelated organisms evolve similar traits because they occupy similar environments and face similar selection pressures.

Divergent Evolution

Process where organisms with a common ancestor evolve different features to adapt to different habitats or selection pressures.

Adaptive Radiation

The formation of many different species from a single common ancestor in a short amount of time.

Gradualism

The Darwinian model of evolution suggesting that species change in a constant and directional fashion over generations.

Punctuated Equilibrium

The theory that populations undergo rapid periods of evolutionary change followed by long periods of stability.

Transitional Species

Organisms that show intermediate traits between two different groups, such as the Archaeopteryx bridging dinosaurs and birds.

Vestigial Structures

Structures that have lost their original function over time through evolution, such as the human appendix.

Biogeography

The study of the geographical distribution of species and how processes like continental drift influence their evolution.

Law of Superposition

A stratigraphic principle stating that in a sequence of rocks, the oldest fossils are found at the bottom and the youngest at the top.

Radiometric Dating

A type of absolute dating that measures the proportion of radioactive isotopes, such as Carbon-$14$, to determine fossil age.

Olympic Village Effect

The term describing the rapid evolution of cane toads at the expansion frontier, resulting in faster but more disease-prone individuals.