1.5 Flashcards
What is Stabilizing Selection?
Abnormal variations die or do not mate, resulting in a stable, similar-looking population.
Example: Strange coloration patterns, abnormal rituals, weird silver fox traits.
What occurs during Directional Selection?
One extreme variation is better at survival than the other normal phenotypes, causing the population to shift towards that extreme member.
Example: Increased size of horses and antibiotic resistant bacteria.
What is Disruptive Selection?
Normal members die while extreme members survive, which may lead to the creation of two species from one.
Example: Deer mouse (meadow) and white-footed mouse (woodland).
What is Lamarck’s Theory of Inheritance of Acquired Characteristics?
An organism changes to become more suited to its environment over many generations, and structures developed during an organism’s lifetime can be passed on to offspring.
Examples: Bird ancestors striving to fly, giraffe ancestors stretching their legs and necks.
What was the downfall of Lamarck’s Theory?
The assumption that a structure acquired during an organism’s lifetime can be passed on to its offspring was disproven.
Example: Experiment with mice having their tails cut off showing normal tails in offspring.
What was Darwin’s hypothesis about giraffes?
Longer neck giraffes could reach food, while shorter neck giraffes would die from hunger, leading to the survival and breeding of long-necked giraffes.
Concept of ‘Survival Of The Fittest’.
How does evolution through natural selection occur?
It takes place over a very long period of time, but there are exceptions.
Example: Peppered Moth and Industrial Melanism.
What is the significance of the Peppered Moth example?
It illustrates ‘Survival of the Fittest’ that occurred rapidly due to environmental changes during the Industrial Revolution.
Light moths were eaten when trees were darkened by soot, while dark moths survived.
Fill in the blank: In Stabilizing Selection, _______ variations die or do not mate.
abnormal
True or False: Directional Selection leads to the death of normal phenotypes.
False
Fill in the blank: Lamarck believed that parts of a body used more will become more _______.
developed
What is ‘Industrial Melanism’?
A phenomenon where darker individuals become more prevalent due to environmental changes, as seen in Peppered Moths during the Industrial Revolution.
In the early 1800s, light-colored moths were better camouflaged, but after industrialization, dark moths survived better.
