Biology AS91603

Abiotic Factors

Non-living physical and chemical components in the eco system e.g. Water, air, soil, sunlight, minerals and temperature

Biotic Factors

Living things that directly or indirectly affect the ecosystem they live in e.g. Prey, parasitism, disease and predation

Fundamental Niche

Describes the full range of environmental conditions and resources an organism can possibly occupy and use, especially when limiting factors are absent in its habitat.

Realised Niche

Where the organism is actually found due to limiting factors such as competition, or lack of resources.

Exploitative Competition

When one species either reduces or more efficiently uses a resource, and therefore depletes the availability of that resource to the other species.

Interference Competition

When two species physically interfere with one another by aggressively attempting to exclude one another from particular habitats.

Competitive Exclusion Principal

Two species that use the same limiting resource while occupying the same niche cannot coexist and must diverge from one another over time in order for the species to coexist.

Niche Differentiation

A process by which natural selection drives competing species into different patterns of resource use or different niches.

Spatial Displacement

Competing species use the same resource by occupying different areas or habitats.

Temporal Displacement

Species eliminate direct competition by utilizing the same resource at different times.

Morphological Differentiation

Competing species evolve differing morphologies to allow them to use a resource in different ways.

Local Extinction

When a species ceases to exist within the geographic area of study.

Mutualism

The existence of two organisms of different species in a relationship in which each individual benefits from the activity of the other. Is a type of symbiosis.

Commensalism

Class of relationships between two organisms where one organism benefits without affecting the other.

Exploitation

The action of making use of and benefiting from resources.

Antagonistic Relationships

The population sizes of the organism benefited and the organism detrimentally affected are related.

Herbivory

The consumption of plant materials by animals, herbivores are animals which are adapted to eat plants.

Parasitism

When an individual organism, the parasite, consumes nutrients from another organism, its host, resulting in a decrease in fitness to the host.

Nocturnal

Active at night.

Diurnal

Active at day.

Crepuscular

Active at dawn and dusk.

Tidal Rhythm

Caused by rotation of the moon, and the gravitational pull.

Lunar Rhythms

Rhythms are linked to the rotation of the moon around the Earth, and much less common than daily or tidal rhythms. About monthly.

Semi-Lunar Rhythms

Rhythms that are also associated with the moon, but there are 2 cycles every lunar month.

Endogenous Rhythms

Internally driven rhythms. e.g. biological clocks.

Exogenous Rhythms

Externally driven i.e. by external stimuli.

Zeitgeber

External environmental cue that resets the biological clock.

Entrainment

The process of resetting the internal clock.

Circadian

A rhythm that matches the movement of the tides and has a period of 12.5 hrs.

Circa Lunar

A rhythm that cycles over an approximately 29.5 day period.

Circa Annual

An annual rhythm.

Kineses (definition)

Innate locomotory behaviours involving non-directional movements in response to an external stimuli.

Kineses (Actually Explained)

A non-directional response to a stimulus in which the speed of movement or the rate of turning is proportional to the stimulus intensity.

Orthokineses

The rate of movement is dependant on the stimulus intensity.

Klinokineses

The rate of turning is related to the stimulus intensity.

Taxes (Definiton)

An innate locomotory behaviour involving directional movement s in response to external stimuli.

Taxes (Actually explained)

Involve orientation and movement in response to a directional stimulus or a gradient in stimulus intensity.

Klinotaxes

An organism continuously samples the environment with a single receptor to compare the stimulus over time.

Innate

Genetically programmed.

Touch

Thigmo

Light

Photo

Gravity

Gravi

Chemicals

Chemo

Water

Hydro

Temperature

Thermo

Tropotaxes

An organism with bilateral sense organs determines the direction of a stimulus through simultaneous comparison.

Open Membership

Membership is temporary - individuals may come and go.

Closed Membership

Membership is stable and group members recognise each other.

Courtship

A succession of signals that are exchanged between males and females, reducing aggression, and which culminates in mating. Ensures that the two animals are of the same species and can be a trigger for nest building or ovulation.

Pair Bond

A stable, usually long lasting relationship between animals of the oppisite sex that ensures cooperative behaviour in mating and the rearing of young.

R-Strategists

Produce large numbers of oppspring but with no parental care and hope that some survive to continue to the next generation. The health of the existing generation is unaffected by this kind of breeding.

K-Strategists

Produce only a few offspring but invest heavily in parental care to ensure maximum survival rate for the next generation.

Oviparous

Lay eggs.

Viviparous

Produce live young.

Home Range

Is the geographical area that an animal seldom leaves. It becomes familiar with it, covers it regularly in search of food and mates and makes its home with in it. Are not defended.

Teritory

The area that an animal marks and defends around its home base. It is defended by aggressive behaviour. Strongest attacks will be against members of the same sex.

Tropism

Movements of plant parts by growth. The direction of the growth depends on the direction of the stimulus.

Positive Tropisms

Growth movements towards a stimulus (plants).

Negative Tropisms

Growth movements away from a stimulus (plants).

Dia

Tropism at right angles to the stimulus.

Nastic Movements

Non directional responses by plants.

Meristems, division, elongation, specialisation

Cell division occurs in plants in _________ which are found at the tip of the shoot root. The length of a plant shoot or root is increased by cell ________, cell __________ and cell _____________.