Objective # 4
Module 1B – Unifying Concepts in Biology
„ What
is Biology?
The scientific study of living organisms.
Explain each of the following
unifying concepts in biology:
All of the things we have said so far
about science in general also apply to
biology.
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2
Objective 4a
Objective 4 b
Living organisms and
nonliving matter are composed of
the same chemical elements and
are governed by the same natural
laws.
Living organisms possess
a much higher level of complexity
and organization than is found in
non-living matter.
„ Concept:
„ Concept:
3
Objective 4 b
„
The matter that makes up
living systems is organized
according to a hierarchy: a
system of increasingly
larger and more complex
units, where each unit is
composed of units from
the previous level.
„
¾
¾
¾
¾
¾
¾
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Objective 4 b
Levels of Organization of
Matter
„ Quarks
„ Subatomic particles
„ Atoms
„ Molecules
„ Organelles
„ Cells
„ Tissues
E.g. Writing
Letters
Words
Sentences
Paragraphs
Chapters
Volumes
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„
„
„
„
„
„
„
„
Organs
Organ systems
Complex organisms
Populations
Species
Communities
Ecosystems
Biosphere
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1
Objective 4 c
Objective 4 d
Cells are the basic units
of structure and function in living
organisms.
In order to maintain their
high level of organization, as well
as grow and reproduce, living
organisms require a continual input
of matter and energy.
„ Concept:
„ Concept:
¾Cells
are the smallest units that have
all the characteristics of life
¾All organisms are composed of cells
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Objective 4 d
Objective 4 d
„ Energy:
„ Matter:
¾ The
¾ Many
second law of thermodynamics
tells us that all things have a natural
tendency to become more and more
disorganized.
¾ In order to counteract this tendency,
an input of energy is required.
organisms use complex
molecules as a source of energy.
¾ Matter is also needed to produce new
cells for growth and reproduction.
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10
Objective 4 e
„ Concept:
Objective 4 f
In order to maintain their
high level of organization, as well
as grow and reproduce, living
organisms require a set of genetic
instructions.
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Living organisms are
adapted to their environment and
evolve in response to their
environment.
„ Concept:
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2
Objective 4 f
Objective 4 f
„ Adaptation:
„ Evolution
Any characteristic of an organism that
helps it to survive and /or reproduce.
vs. Revolution
¾Evolution: slow, gradual change
¾Evolution in biology: a gradual
change in the genetic make-up of a
population from one generation to
the next
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Objective 4 g
Objective 4 g
Evolution accounts for
both the unity and diversity of life.
„ Concept:
„ The
unity of life:
¾All living organisms share certain
characteristics. This is because they
have inherited those characteristics
from a common ancestor.
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Objective 4 g
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Objective # 5
„ The
diversity of life:
¾Millions of different species inhabit
the earth. This diversity was
produced as different populations
were separated from each other and
each evolved its own unique set of
characteristics.
17
Describe the theory of natural
selection along with the major ideas
and evidence that led Darwin and
Wallace to develop the theory of
natural selection.
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3
Objective 5
Objective 5
„ Evolution
is the idea that species
gradually change over time. This idea
has been around since at least the time
of the ancient Greeks and is now
supported by overwhelming evidence.
„ Natural selection is a theory to explain
the mechanism of evolution – what
causes species to change over time.
„ The
origin of the theory of natural
selection can be traced back to 1831,
when a British naturalist named
Charles Darwin was selected to
participate in a 5-year scientific
expedition around the coasts of South
America aboard the H.M.S. Beagle.
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Objective 5
Objective 5
During this voyage, Darwin made many
observations that convinced him that
evolution had taken place.
„ For example, his studies of how the
characteristics of similar species vary from
place to place led him to conclude that
species often change as they migrate and
adapt to new environments:
„
British Isles
NORTH
PACIFIC
OCEAN
NORTH
AMERICA
Galápag os
Islands
Western
Isles
Valparaiso
Society
Islands
ASIA
NORTH
PACIFIC
OCEAN
Canary
Islands
Cape Verde
Islands
SOUTH
AMERICA
Bahia
Marquesas
EUROPE
NORTH
ATLANTIC
OCEAN
Philippine
Islands
AFRICA
INDIAN
OCEAN
Madagascar
Ascension
St. Helena
Rio de Janeiro
Equator
Keeling
Islands
Mauritius
Bourbon Island
Friendly
Islands
AUSTRALIA
Sydney
Montevideo
Buenos Aires
Port Desire
Straits of Magellan
Corn
Falkland
Islands
Cape of
Good Hope
King George’s
Sound
Hobart
SOUTH
ATLANTIC
OCEAN
New
Zealand
Tierra del Fuego
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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Objective 5
Objective 5
Galapagos Finches:
Based on his observations, as well as the
ideas of other scientists such as Lyell and
Malthus, Darwin wrote a description of the
theory of natural selection in 1842, but for
some reason he didn’t publish it.
„ Then, in 1858, another British naturalist,
named Alfred Russel Wallace, sent Darwin
an essay in which he described the same
theory that Darwin had developed.
„
Large ground finch (seeds)
Vegetarian finch (buds)
Cactus ground finch
(cactus fruits and flowers)
Woodpecker finch (insects)
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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Objective 5
Objective 5
„ This
convinced Darwin to publish his
ideas. In 1859, he described his theory
in one of the most famous and
influential books of all time: On the
1) GENETIC VARIATION:
There is variation among the members of
a population. Some of this variation is
genetic.
The ultimate source of genetic variation is
mutation.
Mutations are random changes in the
genetic material.
Origin of Species by Means of Natural
Selection.
„ We
can describe the theory of natural
selection in 3 parts:
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Objective 5
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Objective 5
2) STRUGGLE FOR EXISTENCE:
A population produces many more
offspring than can survive long enough to
reproduce.
This idea was based on Thomas Malthus’s
Essay on the Principle of Population –
populations tend to increase faster than
their food supply.
3) DIFFERENTIAL REPRODUCTION:
Due to genetic variation, some
individuals have traits that increase their
chances for survival and reproduction.
The genetic traits of better adapted
individuals will become more common
each generation, while the traits of less
well adapted individual die out.
This leads to a struggle for existence.
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Objective 5
Although the importance of natural
selection as a mechanism of evolution is
now widely accepted, scientists have
identified several other mechanisms that can
also cause a change in the genetic makeup of
a population from one generation to the
next.
„ The relative importance of these various
mechanisms of evolution is currently the
subject of much research and debate.
„
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