Selection and evolution

characteristics of organisms are affected by ...

• genotype only

• genotype + influences of the environment

• phenotype+ genotype

• influences of the environment only

the correct example of the influence of environment on adult form occurs in the honey bee :

• The drones are the community’s females and they develop from unfertilised eggs

• The workers are the community’s males and they develop from unfertilised eggs

• The queen and the drones develop from fertilised eggs and have identical genotypes

• The queen and the workers develop from fertilised eggs and have identical genotypes

a mechanism which maintains a favourable characteristic and the alleles responsible for them, and eliminates variants and abnormalities that are useless or harmful

• Stabilising selection

• Directional selection

• Disruptive selection

• Balancing selection

A process which actively maintains multiple alleles in the gene pool of a population. An example of this is sickle cell trait.

• Stabilising selection

• Directional selection

• Disruptive selection

• Balancing selection

occurs when particular environment conditions favour the extremes of a phenotypic range over intermediate phenotypes. For example: colonisation by plants of mine waste tips.

• Stabilising selection

• Directional selection

• Disruptive selection

• Balancing selection

A result from changing environmental conditions. The majority of an existing form of an organism may no longer be best suited to the environment

• Stabilising selection

• Directional selection

• Disruptive selection

• Balancing selection

these are NOT a "disturbing factors":

• Selection, Founder effect, Mutation

• Mutation, Genetic drift, Emigration

• mutation, mating, competition

• immigration, Selection, Founder effect

extreme cold, devastating flooding or prolonged drought, a natural population may be reduced to a very few survivors – creates a ....

• genetic bottleneck.

• Founder effect

• mutation

• imigration

A small group of a large breeding population may become isolated, possibly due to a barrier that arises within part of the territory, or when a small group wander away, or are carried away by chance

• genetic bottleneck.

• Founder effect

• mutation

• imigration

introduce new genes into populations

• genetic bottleneck.

• Founder effect

• mutation

• imigration