Mechanisms of Evolution and Speciation
The process by which species change over time due to genetic variation.
Evolution
Reproductive isolation occurs when populations can no longer do this.
Interbreed
A simple, automatic response to a stimulus.
Reflex
Growth of plants towards light.
Phototropism
The strategy where an organism produces many offspring with little parental care.
R-Strategy
Variation in populations can arise through this change in DNA.
Mutation
Isolation caused by physical barriers, like mountains or rivers.
Geographic Isolation
Behaviour that is genetically programmed and not learned.
Innate Behaviour
The hormone responsible for stem elongation.
Auxin
The strategy where an organism produces few offspring but invests significant parental care.
K-Strategy
The mechanism where individuals with advantageous traits are more likely to survive and reproduce.
Natural Selection
Isolation caused by differences in mating rituals, behaviours, or communication.
Behavioural isolation
Seasonal movement of animals in response to environmental changes.
Migration
Growth response of plant roots to gravity.
Gravi- or Geo- tropism
Competition between members of the same species for resources such as food, territory, or mates.
Intraspecific Competition
This type of selection favours extreme traits at both ends of the spectrum.
Disruptive Selection
A type of selection where intermediate traits are favoured.
Stabilising selection
Internal clock in animals controlling daily activity cycles.
Circadian Rhythm
Internal timing mechanism that allows plants to flower at the right season.
Biological clock or Photoperiodism
Structured groups where individuals have defined roles and ranks.
Structured Hierarchies
Formation of a new species due to geographic separation.
Allopatric Speciation
Type of speciation that occurs without geographic isolation.
Sympatric Speciation
Behavioural adaptation that reduces competition for resources or mates.
Territoriality
The minimum or maximum day length needed to trigger flowering in a plant.
Critical Day Length
A system in which individuals cooperate and live in organised groups, often improving survival and reproductive success.
Complex Social Groups