Unit IV – Evolution, Change, and Diversity
(15% of Public Exam)
Ch. 19 – Introducing Evolution (pp. 643 – 671)
→ what evolution is
→ natural and artificial selection
→ early ideas about evolution → evidence used to support
evolution
Ch. 20 – Mechanisms of Evolution (pp. 672-699)
( 1 Lab)
→ population genetics
→ various mechanisms of evolution
→ Hardy-Weinberg Principle
Ch. 21 – Adaptation and Speciation (pp. 700-737) ( 1 STSE)
→ types of adaptations
→ theories on origin of life on Earth
→ how species form
19.1 Diversity of Life p. 643
→ what is evolution?
→ natural selection
→ artificial selection
What do you think Evolution is?
Evolution
• the relative change in the
characteristics of
populations that occur over
successive generations
• Read about it in you book
(Section 19.1)
Evolution
• the relative change in the
characteristics of
populations that occur over
successive generations
• Read about it in you book
(Section 19.1)
Evolution
• the relative change in the characteristics of
populations that occur over successive generations
Evolution
• change in the
• characteristics of
populations that occur
• over successive generations
Adaptations in Evolution
a particular:
Structure (leaf, Leg Beak)
–Physiology (digestion, metabolic rate)
–behavior (nocturnal, arboreal)
–
that helps an organism survive and reproduce in a
particular environment.
What types of adaptations are these?
Remember Adaptations in Evolution
a particular Structure (leaf, Leg, Beak) or
Physiology (digestion, metabolic rate) or
behavior (nocturnal, arboreal) that helps
an organism survive and reproduce in a
particular environment.
Variation in a Population
• the form of a trait or significant deviation from the normal
biological form, function, or structure.
• Another word for Variation might be range
• What is the variation or range in height among humans?
• What is the variation or range in running speed?
• What is the variation or range in intelligence?
• All populations have variation (it easier to see in humans)
Natural Selection
Natural selection – process whereby the
characteristics of a population of organisms
change because individuals with certain inherited
traits survive specific local environmental
conditions. (Survival of the fittest)
Individuals survive but populations change!!
It is important to note that natural selection
does not cause changes in individual organisms,
rather entire populations of organisms over time.
Natural Selection & Peppered Moths
p. 644-645
Selective pressure
environmental condition or conditions that select for
certain characteristics of individuals and select against
others.
What was the selective pressure for the peppered Moth?
Artificial Selection
human selection of a particular trait
Ex. Faster horses,
disease-resistant plants,
breeding of dogs