On the Termination of Species

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On the Termination of Species
Current Issues in Biology, Volume 1
Scientific American
PowerPoint® Lectures
Lectures by Chris Romero, Front Range Community College
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
On the Termination of Species
Concept Review
• Oxford zoologist Robert M. May and other scientists
claim that humans could be causing the sixth great wave
of mass extinctions on Earth.
• May estimates that the extinction rate of organisms on
Earth has accelerated during the past 100 years to
roughly 1,000 times what it was before humans showed
up.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
On the Termination of Species
Concept Review
• Most scientists identify five major mass extinctions in
Earth’s history. A mass extinction is any set of events that
leads to the extinction of a significant number of species.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
On the Termination of Species
Concept Review
• Some scientists dispute the claim that the Earth is
currently experiencing a mass extinction event-this time,
caused by humans.
• These scientists have reported that the methods used to
calculate extinction rates are flawed by false assumptions.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
On the Termination of Species
Concept Review
•
Two factors that compound the problem of estimating
extinction are
1. The enormous number of species on the Earth
2. Many of those species are not yet identified.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
On the Termination of Species
Concept Review
• Habitat loss due to
human development
has long been thought
to contribute to
extinction (the “speciesarea relation”), but
recent data has also
proven inconclusive.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
On the Termination of Species
Concept Review
• However, annual forest loss has declined somewhat in
recent years.
• Although projections of extinction rates have been
inconsistent, biology have good reasons to fear that if a
mass extinction hasn’t begun yet, it is imminent.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
On the Termination of Species
Concept Review
• A goal of many scientists has been to promote the
importance of species and habitat conservation.
• Edward O. Wilson, a Harvard professor states, “It turns
out to be a lot easier to persuade a corporate CEO or a
billionaire of the importance of the issue than it is to
convince the American public.”
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
On the Termination of Species
Testing Your Comprehension
How many mass extinctions are known from the fossil
record?
a) 1
b) 5
c) 11
d) 46
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
On the Termination of Species
Testing Your Comprehension
How many mass extinctions are known from the fossil
record?
b) 5
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
On the Termination of Species
Testing Your Comprehension
Which kind of organism comes in more species that the total
species of all the other multicellular organisms combined?
a) Insects
b) Fungi
c) Nematodes
d) Protozoa
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
On the Termination of Species
Testing Your Comprehension
Which kind of organism comes in more species that the total
species of all the other multicellular organisms combined?
a) Insects
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
On the Termination of Species
Testing Your Comprehension
What does the “species-area relation” say about the
relationship between habitat loss and species extinction?
a) As habitat area is lost, the number of species living
in it decreases.
b) As habitat area is lost, the number of species living
in it increases.
c) As habitat area is lost, the number of species living
in it does not change.
d) As habitat area is gained, the number of species
living in it decreases.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
On the Termination of Species
Testing Your Comprehension
What does the “species-area relation” say about the
relationship between habitat loss and species extinction?
a) As habitat area is lost, the number of species living
in it decreases.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
On the Termination of Species
Biology In Society
Given that estimates of extinction rates are uncertain, do
you think it is a good idea to base public policies on the
assumption that species are, in fact, disappearing at
an increasing rate?
Strongly
Agree
A.
B.
C.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
D.
E.
Strongly
Disagree
On the Termination of Species
Thinking About Science
Which of the following is NOT a common argument made by
conservationists in favor of maintaining species diversity?
a) Most of our drugs are derived from natural species.
b) Whole ecosystems provide irreplaceable services to
the biosphere.
c) Humans have a moral obligation to act as stewards
for the diversity of life.
d) Human nutrition depends upon having a wide variety
of natural species to eat.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
On the Termination of Species
Thinking About Science
Which of the following is NOT a common argument made by
conservationists in favor of maintaining species diversity?
d) Human nutrition depends upon having a wide variety
of natural species to eat.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
On the Termination of Species
Thinking About Science
Scientists often become advocates for conservation. How
might advocacy for a cause such as conservation lead to
bias in the research related to the so-called biodiversity
crisis?
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
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