copyright © 2009 pearson education, inc. © 2013 pearson education, inc. powerpoint lecture...

Copyright © 2009 Pearson Education, Inc.

© 2013 Pearson Education, Inc.

PowerPoint Lecture prepared byJill Feinstein

Richland Community College

Fourth Edition

BIOLOGYScience for Life | with Physiology

Colleen Belk • Virginia Borden Maier

ChapterChapter 8 8

Where Did We Come From?The Evidence for Evolution


1 What is Evolution? – The Process of Evolution

Biological populations Groups of individuals of the same species that are

subdivided from other populations by geography

Biological evolution Change in the characteristics of a population of

organisms that occurs of over the course of generations.

Evolutionary changes are inherited via genes.

Other changes may take place because of environmental changes and are not necessarily evolutionary.



Pesticide resistant lice are an example of biological evolution.



Natural selection – the differential survival and reproduction of individuals in a population

Process by which populations adapt to varying environments

Examples:

Pesticide resistance in crop-eating insects

Antibiotic resistance in infectious bacteria



Microevolution – changes that occur within a species and the characteristics of a population. Easily observed, relatively non-controversial.

Macroevolution – changes that occur, as a result of microevolution, over long periods of time and result in the origin of new species. Controversial among non-biologists.


1 What is Evolution? – The Theory of Evolution

Ambiguity of the word “theory”

Everyday usage: theory = best guess, or tentative explanation

Scientific usage: theory = body of accepted general principles, supported by many lines of evidence.

Examples: atomic theory, gravity, germ theory.



Theory of evolution

All species present on earth today are descendents of a single common ancestor, and all species represent the product of millions of years of accumulated evolutionary changes.



Theory of common descent


Animation: Principles of EvolutionClick “Go to Animation” / Click “Play”

BioFlix: Mechanisms of Evolution


2 Charles Darwin and the Theory of Evolution

Theory of Evolution is sometimes called “Darwinism” because Charles Darwin is largely credited with introducing the concept to mainstream science.

Many philosophers of science before Darwin had notions of organisms changing over time.

Anaximander – Greek philosopher who suggested that humans evolved from fish that had moved onto land

Lamarck – published ideas about inheritance of acquired traits in 1809


2 Charles Darwin and the Theory of Evolution - The Voyage of the Beagle

At age 22, Darwin set sail as ship’s naturalist aboard the HMS Beagle on a five year long trip.

Darwin’s job was to collect and observe “anything worthy to be noted for natural history.”

Darwin had a book by Lyell, Principles of Geology, which postulated earth was old and changes occurred over long periods of time.



The following had influences on Darwin during the voyage: Rainforests of Brazil Fossils that he collected Birds and reptiles of the Galapagos Islands


2 Charles Darwin and the Theory of Evolution - Developing the Hypothesis of Common Descent

Darwin returned to England in 1836, but did not publish his ideas immediately.

Spent about 20 years refining his ideas

Learned about animal husbandry (selective breeding)

Finally published On the Origin of Species in 1858


2 Alternative Ideas on the Origins and Relationship among Organisms

Theory of common descent is controversial. There are some possible alternative hypotheses that can be tested against available data.

Static model hypothesis

Transformation hypothesis

Separate types


2 Alternative Ideas on the Origins and Relationship among Organisms

Graphical representations of theory of common descent and alternative hypotheses:

Figure 9.7


3 Examining the Evidence for Common Descent

Several lines of biological evidence point to a common ancestor:

Biological classification

Anatomical similarities between organisms

Useless traits in modern species

Shared developmental pathways

DNA similarities

Distribution of organisms on earth (biogeography)

Fossil evidence



Biological classification implies common ancestry.

Linnaean Classification

Gives each species a two-part or binomial name in Latin

Carolus Linnaeus groups organisms in a hierarchy going from broadest to narrowest groupings



Anatomical homology

Mammalian forelimbs have the same set of bones. The underlying structure is similar despite the very different functions.



Useless traits in modern species

Vestigial traits are traits that function in one organism but are greatly reduced in others

For example:

Ostrich and penguins form wings but do not fly because the wings are non-functional

Humans have a tailbone by have no tail


3 Examining the Evidence for Common Descent –Developmental Homologies

A consequence of shared developmental pathways is similarity among chordate embryos


3 Examining the Evidence for Common Descent – Molecular Homology

DNA similarities

Birds in same genus have DNA that is more similar to one another, while distantly-classified birds have DNA that is less similar.

Molecular clock allows the use of DNA sequence differences between species to determine when they diverged from their common ancestor.


3 Examining the Evidence for Common Descent – Biogeography

Biogeography is the distribution of species on earth.

Different species of mockingbird found on Galapagos all resemble another species found on the mainland.


3 Examining the Evidence for Common Descent –The Fossil Record

Fossils are remains of living organisms left in soil or rock. Horse fossils provide a good sequence of

evolutionary change within a lineage.


3 Examining the Evidence for Common Descent – The Fossil Record

Fossilization is the formation of fossils


3 Examining the Evidence for Common Descent –Fossil Record

Bipedal humans have some unique anatomical traits, such as features of hips, knees, and skull.

Anatomical differences between humans and chimpanzees allow for identification of fossils


3 Examining the Evidence for Common Descent –Radiometric Dating

Radiometric dating Used to determine age of rocks Relies on decay of radioactive isotopes into daughter

products The rate of decay is measured by the element’s

half-life


3 Examining the Evidence for Common Descent –Radiometric Dating

Using radiometric dating, scientists have estimated the age of fossil hominims.


3 Examining the Evidence for Common Descent – Radiometric Dating

Trends in human evolution

Larger brains, Flatter face, Reduced jaw size


4 Are Alternatives to the Theory of Evolution Equally Valid?

The same lines of evidence that support common descent can be used to look for the closest relatives of humans.

Table 10.1 summarizes the evidence for common descent.



Weighing the alternatives


4 Are Alternatives to the Theory of Evolution Equally Valid? – The Origin of Life

The origin of life

Evolution is the study of how life changes.

It doesn’t really address issue of how life began.

Experiment evidence does give some clues about beginnings of life.

Evidence for the theory of common descent demonstrates consilience.



Evolutionary theory informs all aspects of modern biology.

Evolutionary theory helps us understand the function of human genes.

Evolutionary theory is important to understanding species interactions.

Evolutionary theory is important for predicting the biological consequences of climate change.


Which of the following is not an example of a scientific theory?

gravity

evolution

intelligent design

all of the above


The head lice that have become resistant to the pesticide permethrin demonstrate microevolution.

True or False: The individual head lice have evolved.

True.

False.


Giraffes stretched their necks by reaching for high leaves. They then passed this longer neck to their offspring. Who thought of this idea?

Darwin

Lyell

Lamarck

Wallace


Which correctly lists the classification levels from broadest to narrowest groupings?

Order, Family, Genus, Species

Family, Genus, Order, Species

Species, Genus, Family, Order

Order, Species, Family, Genus


Which of the following do not belong in the order Primates.

monkeys

humans

apes

all of the above belong to the order Primates


Which of the following is an example of a vestigial trait?

a human tailbone

a dolphin’s blowhole

a gorilla’s opposable thumb

a penguin’s flippers


Where did humans evolve?

North America

Europe

Africa

Galapagos Islands


True or False: Differences in DNA sequences can help determine when two species diverged from their common ancestor.

True.

False.


What proposed mechanism of evolution is shown in this figure?

static model

transformation

separate types

common descent


What is shown by the y-axis of this graph?

percentage of parent element remaining

time (in millions of years)

depth of burial

number of fossils found

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