Chapter 1: Adaptation by Natural Selection
1. What Is Adaptation?
Components of an organism that help it survive and reproduce.
The human eye is an example of a complex adaptation.
Before Darwin, adaptation was explained as the work of a heavenly designer.
2. Darwin's Theory of Adaptation
After medical school, Darwin spent time on the H.M.S. Beagle charting the coast of South America and
studying the flora and fauna there.
Darwin returned to London and developed three postulates of adaptation:
Population increases infinitely, but the environment is finite.
Organisms vary, and variation affects survival.
Variation is heritable.
Peter and Rosemary Grant of Princeton University studied the finches for years.
Drought struck Daphne Major in the late 1970s, and plant life dwindled.
Large, hard seeds and beak-size variation contributed to adaptation.
Finches with deeper beaks survived in larger numbers than those with smaller beaks (Fig. 1.9).
Beak depth was passed on to new generations (Fig. 1.10), causing a 4% increase in average beak
depth in the finch population.
The Grants’s long-term research shows stabilizing selection and equilibrium in beak size (Fig
Individual versus species
Darwin put forward that a species is dynamic—a population made up of individuals.
Selection creates adaptations that are beneficial to the individual, not necessarily to the population
3. What Are Complex Adaptations?
Continuous variation is important for complex adaptations.
Complex adaptations are the result of small, random variations.
Complex adaptations require all intermediate steps to be useful.
Example: Human eye (Fig. 1.15)
Convergent evolution occurs when a similar adaptation occurs in unrelated groups of animals.
Examples: Eyes, marsupials
4. How Fast Does Evolution Occur?
Change can occur rapidly. Examples include:
Beak morphology of Galápagos finches
Body size of Jersey elk
Nilsson and Pelger of Lund University simulated the evolution of the eye in fish and found that this
complex structure could evolve in less than a million years.
5. Problems Darwin Could Not Solve
Blending inheritance would eliminate variation by making each individual the average of its parents.
Natural selection would also eliminate variation by removing variants from populations.
How can new traits be introduced to a population?
Chapter 5: Primate Diversity and Ecology
1. Why Study Primates?
Studying the behavior of primates gives us insight into our ancestors’ behavior, also known as “reasoning
Studying the diversity of organisms allows us to see how adaptation works under different selective
pressures, also known as “reasoning by analogy.”
2. What Are Primates?
Primates are our closest relatives and comprise an extremely diverse order.
Characteristics that define the primate order include:
Opposable big toe and prehensile hands
Nails instead of claws; fingerprints
Highly developed vision
Small litters of young with slow gestation and maturation periods
Unspecialized molars and unique dental pattern
3. Where Do Primates Live?
Mainly in the tropical areas of Asia, Africa, South America, Mexico, and Central America.
4. Primate Taxonomy
Many are nocturnal and have developed adaptations for life in the dark.
This suborder includes lemurs, lorises, and tarsiers.
Larger than prosimians, they are normally active in the day, rely on vision rather than smell, and
live in social groups.
This suborder includes New World monkeys, Old World monkeys, and humans.
5. Primate Ecology
An animal’s energy requirements depend on:
Primates require protein, carbohydrates, fats and oils, vitamins and minerals, and water, which they get
from a variety of sources.
Four general types of primate diets are frugivore, folivore, insectivore, and gummivore. Each are affected
by primate dental patterns, dental morphology, and gut morphology (Figure 5.18).
Primate activity is regularly patterned and can be graphically depicted as having a “time budget” (Figure
Primate groups have relatively fixed ranges in which they live and move. These home ranges include
access to food and resting places and are often defended by territorial behavior.
Primates need to be concerned about predation, and some have developed antipredator strategies.
6. Social Primates
Forms of primate social groups:
Chapter 6: Primate Mating Systems
1. Mating Systems Are Adaptive
Primate behavior is strategic in that it occurs in a specific functional context. Examples include mating,
foraging, and parenting.
2. Evolution of Reproductive Strategies
Selection pressures influence the amount and pattern of parental investment.
Mammalian anatomy requires primate females to invest in their offspring.
3. Female Reproductive Strategies
Female primates are heavily invested in their offspring, which are slow to develop because of their large
Females need access to good nutrition for reproductive success.
Female fertility declines in old age.
High-ranking females produce more offspring than low-ranking females because of access to necessary
A dominance hierarchy or a dominance matrix can be used to describe competitive
encounters among members of a primate species.
Social bonds have an effect on reproductive success.
If a mother invests effort in one offspring, she has less effort to invest in others.
Mothers can change their behavior, distancing themselves from their offspring and
allowing them to become independent.
Many primate mothers must wean their infants before they can conceive additional offspring.
4. Male Mating Strategies
Increases male success in competition for mates.
Can have a greater effect on behavior and morphology than other forms of natural
Components of an organism that help it survive and reproduce. The human eye is an example of a complex adaptation. Before darwin, adaptation was explained as the work of a heavenly designer: darwin"s theory of adaptation. After medical school, darwin spent time on the h. m. s. Beagle charting the coast of south america and studying the flora and fauna there. Darwin returned to london and developed three postulates of adaptation: Population increases infinitely, but the environment is finite. Peter and rosemary grant of princeton university studied the finches for years. Drought struck daphne major in the late 1970s, and plant life dwindled. Large, hard seeds and beak-size variation contributed to adaptation. Finches with deeper beaks survived in larger numbers than those with smaller beaks (fig. Beak depth was passed on to new generations (fig. 1. 10), causing a 4% increase in average beak depth in the finch population. The grants"s long-term research shows stabilizing selection and equilibrium in beak size (fig.