1. How populations evolve Darwin’s theory of evolution.
Life Science I Dr. Ekaterina (Kate) Vorotnikova Office: Olsen 413b
Lecture 27
How populations evolve
Darwin’s theory of evolution.
(Page ;
Questions: p. 252 #2, 3, 4-7; p.275 # 3-5 )

2. Living organisms are adapted to their environment
A leaf mantid in Costa Rica
A flower mantid
in Malaysia
Campbell, Neil A., Jane B. Reece, Martha R. Taylor, Eric J. Simon, Biology: Concepts & Connections, 5th ed., Figure 13.5A Camouflage as an example of evolutionary adaptation; a leaf mantid in Costa Rica.
The leaf insect has a body shape, coloration, and swaying movement that enable it to avoid predation as it feeds on plant leaves.
Camouflage as an example of evolutionary adaptation.

3. Cockleburs fruits may be carried by animal fur.
Figure 17.10B Cockleburs fruits may be carried by animal fur.
Cockleburs produce a spiny fruit that attaches to animal fur, dispersing the seeds in their environment.
Cockleburs fruits may be carried by animal fur.
Cockleburs produce a spiny fruit that attaches to animal fur, dispersing the seeds in their environment.

4. Haltere
Campbell, Neil A., Jane B. Reece, Martha R. Taylor, Eric J. Simon, Biology: Concepts & Connections, 5th ed., Figure 18.12F A mosquito
Female mosquitoes can sense and find warm-blooded hosts and have piercing, sucking mouthparts that allow them to suck the host's blood.
A mosquito
Female mosquitoes can sense and find warm-blooded hosts and have piercing, sucking mouthparts that allow them to suck the host's blood.

5. Blue-footed boobies have a streamlined body and bill, allowing them to swim well. They have two specialized glands, one that secretes oil at the base of the tail to keep their plumage waterproof, and another in the eye socket that accumulates salt from body fluids and excretes it from the nasal cavity.
The booby’s big webbed feet, streamlined shape, large tail and specialized salt-excreting glands are all good examples of evolutionary adaptations, inherited traits that enhance organism’s ability to survive and reproduce in a particular environment
Blue-footed boobies have a streamlined body and bill, allowing them to swim well. They have two specialized glands, one that secretes oil at the base of the tail to keep their plumage waterproof, and another in the eye socket that secretes salt to maintain healthy levels.

6. Blue-footed boobies have a streamlined body and bill, allowing them to swim well. They have two specialized glands, one that secretes oil at the base of the tail to keep their plumage waterproof, and another in the eye socket that secretes salt to maintain healthy levels.

7. Behavioral adaptations Structural adaptations Biochemical adaptations
What is an adaptation?
Behavioral adaptations
Structural adaptations
Biochemical adaptations
Physiological adaptations
Blue-footed boobies have a streamlined body and bill, allowing them to swim well. They have two specialized glands, one that secretes oil at the base of the tail to keep their plumage waterproof, and another in the eye socket that secretes salt to maintain healthy levels.

8. DARWIN’S THEORY OF EVOLUTION
Earth’s species are descendants of ancestral organisms that were different from those living today
Copyright © 2009 Pearson Education, Inc.

9. Jean Baptiste Lamarck suggested that life on Earth evolves
The Greek philosopher Aristotle viewed species as perfect and unchanging
In the century prior to Darwin, the study of fossils suggested that species had changed over time.
Jean Baptiste Lamarck suggested that life on Earth evolves
His proposed mechanisms:
Use and disuse
Inheritance of acquired characteristics
Darwin was influenced by Lyell’s Principles of Geology
He came to realize that the Earth was very old and that, over time, present-day species have arisen from ancestral species by natural processes
Student Misconceptions and Concerns
1. Students often believe that Charles Darwin was the first to suggest that life evolves: the early contributions by Greek philosophers such as Anaximander and the work of Jean Baptiste de Lamarck are unappreciated. Consider emphasizing this earlier work.
2. Students often misunderstand the basic process of evolution and instead express a Lamarckian point of view. Organisms do not evolve structures because of want or need. Evolution is a passive process in which the environment favors certain traits that exist within a population. Adaptations evolve in populations. Organisms do not actively or willingly evolve.
Teaching Tips
1. Consider beginning your unit on evolution by asking each student to explain how a particular adaptation evolved. The evolution of flight in birds is a good example. Reviewing these student explanations can provide great insight into the misconceptions that students may bring to the class.
2. Many resources related to Charles Darwin are available on the Internet. The following are only a few examples:
and are extensive sites rich with details and references.
includes the texts of The Voyage of the Beagle, The Origin of Species first and sixth editions, and The Descent of Man.
includes details of Charles Darwin’s home.
is an extensive usenet newsgroup devoted to the discussion and debate of biological and physical origins.
Copyright © 2009 Pearson Education, Inc.

10. Drosophila Melanogaster
Culture of Drosophila

11. A portrait of 31-year-old Charles Darwin by George Richmond in 1840
Campbell, Neil, and Jane Reece, Biology, 8th ed., Figure 1.18 Charles Darwin as a young man.
A portrait of 31-year-old Charles Darwin by George Richmond in 1840

12. Figure 1.6A Charles Darwin in 1859.
November 1859

13. Evolution explains the unity and diversity of life
In 1859, Charles Darwin published On the Origin of Species by Means of Natural Selection presenting a strong, logical explanation of descent with modification or evolution
The book accomplished two things
Presented evidence to support the idea of evolution
Proposed a mechanism for evolution called natural selection
Student Misconceptions and Concerns
1. Students often misunderstand the basic process of evolution and instead express a Lamarckian point of view. Organisms do not evolve structures deliberately or out of want or need, and individuals do not evolve. Evolution is a passive process in which the environment favors one or more variations of a trait that naturally exist within a population.
2. Students often believe that Charles Darwin was the first to suggest that life evolves; the early contributions by Greek philosophers and the work of Jean-Baptiste de Lamarck and others may be unappreciated. Consider emphasizing this earlier work in your introduction to Darwin’s contributions.
Teaching Tips
1. Many resources related to Charles Darwin are available on the Internet.
a. General evolution resources:
b. Texts of The Voyage of the Beagle, The Origin of Species (first and sixth editions), and The Descent of Man can be found at
c. Details about Charles Darwin’s home are located at
d. An extensive usenet newsgroup devoted to the discussion and debate of biological and physical origins is at
2. Many games model aspects of natural selection. Here is one that is appropriate for a laboratory exercise. Purchase several bags of dried grocery store beans of diverse sizes and colors. Large lima beans, small white beans, red beans, and black beans are all good options. Consider the beans food for the “predatory” students. To begin, randomly distribute (throw) 100 beans of each of four colors onto a green lawn. Allow individual students to collect beans over a set period, perhaps 2 minutes. Then count the total number of each color of bean collected. Assume that the beans remaining undetected (still in the lawn) reproduce by doubling in number. Calculate the number of beans of each color remaining in the field. For the next round, count out the number of each color to add to the lawn such that the new totals on the lawn will double the number of beans that students did not find in the first “generation”. Before each predatory episode, record the total number of each color of beans that have “survived” in the field. Then let your student predators search for another round (generation). Repeat the process for at least three or four generations. Note what colors of beans have been favored by the environment. Apply Darwin’s observations and inferences to this exercise. Ask students to speculate which colors might have been favored during another season of the year or in another location, such as a parking lot.
Copyright © 2009 Pearson Education, Inc.

14. Natural selection is an editing mechanism
It results from exposure of heritable variations to environmental factors that favor some individuals over others
Over time this results in evolution of new species adapted to particular environments
Evolution is biology’s core theme and explains unity and diversity of life
Student Misconceptions and Concerns
1. Students often misunderstand the basic process of evolution and instead express a Lamarckian point of view. Organisms do not evolve structures deliberately or out of want or need, and individuals do not evolve. Evolution is a passive process in which the environment favors one or more variations of a trait that naturally exist within a population.
2. Students often believe that Charles Darwin was the first to suggest that life evolves; the early contributions by Greek philosophers and the work of Jean-Baptiste de Lamarck and others may be unappreciated. Consider emphasizing this earlier work in your introduction to Darwin’s contributions.
Teaching Tips
1. Many resources related to Charles Darwin are available on the Internet.
a. General evolution resources:
b. Texts of The Voyage of the Beagle, The Origin of Species (first and sixth editions), and The Descent of Man can be found at
c. Details about Charles Darwin’s home are located at
d. An extensive usenet newsgroup devoted to the discussion and debate of biological and physical origins is at
2. Many games model aspects of natural selection. Here is one that is appropriate for a laboratory exercise. Purchase several bags of dried grocery store beans of diverse sizes and colors. Large lima beans, small white beans, red beans, and black beans are all good options. Consider the beans food for the “predatory” students. To begin, randomly distribute (throw) 100 beans of each of four colors onto a green lawn. Allow individual students to collect beans over a set period, perhaps 2 minutes. Then count the total number of each color of bean collected. Assume that the
beans remaining undetected (still in the lawn) reproduce by doubling in number. Calculate the number of beans of each color remaining in the field. For the next round, count out the number of each color to add to the lawn such that the new totals on the lawn will double the number of beans that students did not find in the first “generation”. Before each predatory episode, record the total number of each color of beans that have “survived” in the field. Then let your student predators search for another round (generation). Repeat the process for at least three or four generations. Note what colors of beans have been favored by the environment. Apply Darwin’s observations and inferences to this exercise. Ask students to speculate which colors might have been favored during another season of the year or in another location, such as a parking lot.
Copyright © 2009 Pearson Education, Inc.

15. Inferences Observations Natural selection: unequal reproductive
Darwin proposed natural selection as the mechanism of evolution
Darwin observed that
Organisms produce more offspring than the environment can support
Organisms vary in many traits
Inferences
Observations
Natural selection:
unequal reproductive
success
Individual
variation
Overproduction
of offspring
Evolution
of adaptations
in a population
Darwin reasoned that traits that increase their chance of surviving and reproducing in their environment tend to leave more offspring than others
As a result, favorable traits accumulate in a population over generations

16. Natural selection was inferred by connecting two observations
Individuals within a population inherit different characteristics and vary from other individuals
A particular population of individuals produces more offspring that will survive to produce offspring of their own

17. The pygmy sea horses live in Lembeh Strait in Indonesia
The pygmy sea horses live in Lembeh Strait in Indonesia. They are seen in their habitat among a distinctive type of coral. The sea horses look very much like the coral, which serves both to camouflage the sea horses and to lure their prey into the seeming safety of the branching coral. Darwinian theory says that better-camouflaged sea horses have better reproductive success, and thus pass on more of the genes underlying the camouflage pattern. This would account for the evolution of the striking likeness between this pygmy sea horse and its habitat.
Figure 1.4B Some important properties of life.

18. The voyage of the Beagle (1831–1836).
Great
Britain
Europe
North
America
ATLANTIC
OCEAN
Africa
PACIFIC
OCEAN
Brazil
Equator
The
Galápagos
Islands
PACIFIC
OCEAN
South
America
Pinta
Genovesa
Australia
Marchena
Equator
Santiago
Cape of
Good Hope
Daphne
Islands
Andes
Figure 13.1C The voyage of the Beagle (1831–1836).
In 1831, Darwin joined the Beagle as the ship’s naturalist. He spent 5 years on the ship, which circumnavigated the globe, and he charted the South American coast.
Argentina
Fernandina
Pinzón
Tasmania
Isabela
Santa
Cruz
Cape Horn
New
Zealand
Santa Fe
San
Cristobal
40 km
Florenza
Española
40 miles
The voyage of the Beagle (1831–1836).
In 1831, Darwin joined the Beagle as the ship’s naturalist. He spent 5 years on the ship, which circumnavigated the globe, and he charted the South American coast.

19. Great Britain Europe North America ATLANTIC OCEAN Africa PACIFIC OCEAN
Brazil
Equator
South
America
Australia
Figure 13.1C The voyage of the Beagle (1831–1836).
Cape of
Good Hope
Andes
Argentina
Tasmania
Cape Horn
New
Zealand

20. Media_27\13_01CGalapagosIslands_SV.mpg

21. Figure 13.1A A giant tortoise, one of the unique inhabitants of the Galápagos Islands.
Media_27\13_01ATortoise_SV.mpg

22. A marine iguana basking on lava rocks
Figure 13.1B A marine iguana basking on lava rocks.
A marine iguana basking on lava rocks
Media_27\13_01BMarineIguana_SV.mpg

23. Pink (rosada) iguana found in 1986 and overlooked by Darwin

24. FINCHES FROM GALAPAGOS ARCHIPELAGO

25. A sea voyage helped Darwin frame his theory of evolution
The primary mechanism of evolutionary change producing adaptation of organisms to their environment is natural selection, the differential survival and reproduction of individuals within a population
Media_27\13_01CCharlesDarwin_DV.mpg
What process results in such amazing adaptations?
Student Misconceptions and Concerns
1. Students often believe that Charles Darwin was the first to suggest that life evolves: the early contributions by Greek philosophers such as Anaximander and the work of Jean Baptiste de Lamarck are unappreciated. Consider emphasizing this earlier work.
2. Students often misunderstand the basic process of evolution and instead express a Lamarckian point of view. Organisms do not evolve structures because of want or need. Evolution is a passive process in which the environment favors certain traits that exist within a population. Adaptations evolve in populations. Organisms do not actively or willingly evolve.
Teaching Tips
1. Consider beginning your unit on evolution by asking each student to explain how a particular adaptation evolved. The evolution of flight in birds is a good example. Reviewing these student explanations can provide great insight into the misconceptions that students may bring to the class.
2. Many resources related to Charles Darwin are available on the Internet. The following are only a few examples:
and are extensive sites rich with details and references.
includes the texts of The Voyage of the Beagle, The Origin of Species first and sixth editions, and The Descent of Man.
includes details of Charles Darwin’s home.
is an extensive usenet newsgroup devoted to the discussion and debate of biological and physical origins.
Copyright © 2009 Pearson Education, Inc.

26. Natural selection HIV-1 life cycle.
After binding and fusing to the surface of the host cell, the HIV-1 core enters the host cell. Reverse transcriptase synthesizes proviral double-stranded DNA, which is transported to the nucleus. Integration occurs and the ensuing provirus expresses viral RNA that will synthesize viral proteins using the host's ribosomes. New virions are created by assembly and budding through the infected cell membrane and subsequent maturation due to the actions of protease

27. Darwin found convincing evidence for his ideas in the results of artificial selection, the selective breeding of domesticated plants and animals
Artificial selection: different vegetables produced by selecting variations in different parts of the plant.

28. Note these important points
Note these important points
Population is a group of individuals of the same species living in the same place at the same time
Individuals do not evolve: populations evolve
Natural selection can amplify or diminish only heritable traits; acquired characteristics cannot be passed on to offspring
Evolution is not goal directed and does not lead to perfection; favorable traits vary as environments change
Evolution is a passive process in which the environment favors certain traits that exist within a population.
Adaptations evolve in populations. Organisms do not actively or willingly evolve.
Student Misconceptions and Concerns
1. Students often misunderstand the basic process of evolution and instead express a Lamarckian point of view. Organisms do not evolve structures because of want or need. Evolution is a passive process in which the environment favors certain traits that exist within a population. Adaptations evolve in populations. Organisms do not actively or willingly evolve.
2. Students often think of evolution as a process that improves. As the text notes, an adaptation in one context might be a handicap in another context. Reptiles are not “better” animals than fish. Neither could survive long in the other’s environment. Instead, the adaptations found in reptiles allow them to survive in a terrestrial environment, as those of fish allow them to survive in an aquatic one.
Teaching Tips
1. Students may be asked to consider this question: Can individuals evolve? Sometimes such simple questions require complex answers. Might Lamarck have answered this question differently from Darwin? Module 13.2 addresses this question.
Copyright © 2009 Pearson Education, Inc.

29. Quiz questions to study
Page 179 # 2-4; 6
Page 207 # 2-5
Page 229 # 2-5; 7
Page 252 # 2-4; 6-7
Page 275 # 3-5