Biology - Plant and Animal

Adaptive Advantage

A trait that results in an organism having a greater chance of surviving to reproductive age.

Biological Clock

A mechanism that allows an organism to keep track of time.

Effector

The component that produces the response/action

Endogenous Rhythm

A rhythm that ocntinues without external cues

Entrainment

The synchronisation of biological rhythms by external cues.

Environmental Cue

A signal of trigger from the environment that can entrain an endogenous rhythm and regulates an exogenous one.

Exogenous Rhythm

A pattern that occurs only in response to external cues and which disappears when cues are removed.

Free-running period

The time between the onset of one activity and the next in the absence of environmental cues.

Homing

The ability of an organism to return home across unfamiliar territory

Innate Behaviour

Genetically determined behaviour as opposed to learned behaviours.

Kinesis

Undirected movement of an organism or its parts in a response to an external stimulus.

Klinokinesis

The frequency of changing directions is proportional to intensity of the stimulus.

Learned Behaviour

A behaviour based on experience or passed on from one individual to another by imitation.

Migration

Seasonal movement of a population of animals from one region to another.

Navigation

Ability of an animal to stay on a desired course or find a desired location using environmental cues.

Orthokinesis

Speed of an animal is proportional to the intensity of the stimulus causing the movement.

Phase Shift

The amount of time difference between an entrained endogenous biological rhythm and the same rhythm when the zeitgebers have been removed.

Sensory Receptor

Any part of an organism capable of detecting a stimulus and sending a signal to another part of the organism.

Taxis

Innate behavioural responses of an organism resulting in movement in response to stimuli such as light or the presence of food.

Zeitgeber

An external or environmental cue that entrains an organism’s biological rhythm

Circadian Rhythms

An endogenous rhythm with a free-running period of approximately 24 hours that is generally entrained by a zeitgeber.

Autotroph

An organism that is able to produce complex organic molecules from simpler molecules found in its environment, using an external energy source.

Auxin

A plant hormone which causes elongation in cells in the roots and shoot tips and controls some plant growth processes.

Critical day length

A period of day length that when exceeded triggers flowering in long-day plants or inhibits flowering in short-day plants

Cytokinin

A group of hormones that promote cell division in plant roots and shoots and growth of buds

Ethylene

A plant hormone that promotes the ripening of fruit

Gravitropism

Growth towards (+ve) or away (-ve) a grevitational attraction

Hydrotropism

Growth towards or away from water (or following a concentration gradient)

Long-Day Plant

A plant that is triggered into flowering when nights become shorter than a critical length

Nastic Response

A fast reversible movement that is proportional to the intensity of the stimulus. usually a change in turgor pressure

Nyctinasty

a circadian rhythmic movement of plants in response to the onset of darkness.

Photoperiod

The period of time each day during which an organism receives sunlight

Photoperiodism

The response of an organism to seasonal changes in the photoperiod

Photosynthesis

The process by which plants and some bacteria use the energy from sunlight to produce glucose from carbon dioxide and water.

Phototropism

A growth towards or away from a source of light

Phytochrome

A blue/green pigment found in many plants that regulates various developmental processes, particularly flowering.

Phytohormone

Any of a range of chemicals that regulate plant growth.

Short-day plant

A plant that is triggered into flowering when nights become longer than a critical length

Thigmonastic

A nastic response triggered by touch

Thigmotropism

A change in the direction of growth of a plant troggered by touch

Tropism

A change in the direction of growth triggered by an external stimulus

Allelopathy

The chemical inhibition of other organism by another by the release into the environment of substances acting as germination or growth inhibitors.

Aposematism

A family of anti-predator adaptations in which warning signal is associated with the unpalatability/danger of prey to a potentional predator.

Batesian Mimicry

A harmless species evolved to imitate the warning signals of a harmful species directed at a potential predatory of them both.

Brood Parasite

A parasite that lays eggs in another species nest in the expectation that the species will raise the parasites offspring to maturity

Camouflage

Body structures and/or colouration that makes an organism blend in visually with its environment.

Epiphyte

A plant that grows on another plant, especially one that is not parasitic, such as those that grow on tree trunks in the canopy of forests.

Exploitation

Competition where organisms indirectly compete with other organisms for resources to limit the resources availability to other organisms.

Gause’s Principle

That similar species cannot co-exist for long in the same ecological niche

Habitat

The place where an organism or a population normally lives or occurs.

Hemi-Parasitic

A parasite that only gets a portion of its nutrient requirements from its host.

Herbivory

Ingestion of plant material by herbivores. It usually does not involve the consumption and death of the entire plant.

Interspecific Competition

Competition for resources between members of different species.

Mullerian Mimicry

Occurs when two different species evolve the same/very similar structures and colourations as warnings to potentional predators.

Mutualism

Type of interspecific relationship where both species benefit from the interaction.

Niche

Where an organism fits into an ecological community or ecosystem.

Parasitism

Type of interspecific relationship where one species benefits at the expense of its host species.

Predation

Killing and consuming a prey animal

Symbiosis

When two species live in close proximity and interact because one or both cannot survive without the other.