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Chapter 1
Exploring life
PowerPoint® Lecture Presentations for
Biology
Eighth Edition
Neil Campbell and Jane Reece
Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Overview: Introduction
• Biology is the science of life
• (Bio = life & ology = science)
• Biologists ask questions such as:
– How a single cell develops into an organism
– How the human mind works
– How living things interact in communities
– How changes on Earth occur (organisms living
on Earth are modified) = Evolution
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• A simple, one-sentence definition of life is “Life
is recognized by what living things do”
• 7 properties common to all living organisms:
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(1) Order
(2) Regulation
(5) Response to the
environment
(3) Growth and(4) Energy processing
development
(6) Reproduction
Some important properties of life
‫بعض صفات الحياة الهامة‬
(7) Adaptation
New properties emerge at each level in the
biological hierarchy
• The study of life can be divided into different
levels of biological organization
‫‪Levels of biological organization‬‬
‫النظام البيئي‬
‫جميع العشائر المختلفة المتفاعلة مع ما يحيط‬
‫بها من ماء وهواء وتربة ومناخ في منطقة‬
‫معينة‬
‫الجماعة‪ :‬كل الكائنات المكونة للعشائر‬
‫ذرة‬
‫المختلفة في منطقة معينة‬
‫العشيرة‪ :‬مجموعة من الكائنات‬
‫الحية من نفس النوع تتزاوج‬
‫فيما بينها‬
‫جزيئ‬
‫الخلية‬
‫الكائن‬
‫المحيط الحيوي‬
‫كل األنظمة البيئية على الكرة األرضية‬
‫نسيج‬
‫الجهاز العضوي‬
‫الجهاز التنفسى‬
• The organism (an individual living thing) compose of
:‫• يتكون الكائن )وهو الفرد الحى) من‬
–
Organ systems:
–
Organs : provide specific functions for the organism
–
Tissues - made of groups of similar cells
–
Cells
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• The cell is the lowest level of organization that
can perform all activities required for life
• All cells:
– Are enclosed by a membrane
– Use DNA as their genetic information
– The ability of cells to divide is the basis of:
reproduction, growth, and repair of multicellular
organisms
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
There are two basic types of cells
1) Prokaryotic cell
2) Eukaryotic cells
Prokaryotes
‫أولية النواة‬
Single-celled
No cell nucleus
The genetic material in prokaryotes is not membranebound
Examples include bacteria and archaea
Eukaryotes
‫حقيقية النواة‬
Have "true" nuclei containing their DNA
May be unicellular, as in amoebae
May be multicellular, as in plants and animals
10
• By comparison:
• A eukaryotic cell has: membrane-enclosed
organelles, the largest of which is usually the
nucleus.
• A prokaryotic cell is simpler and usually
smaller, and does not contain a nucleus or
other membrane-enclosed organelles
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Prokaryotic cell
‫خلية أولية النواة‬
Eukaryotic cell
‫خلية حقيقة النواة‬
DNA ‫دنا‬
(no nuclear envelop)
)‫(اليوجد غالف نووي‬
Membrane ‫غشاء‬
Contrasting the size and
complexity of
prokaryotic
and eukaryotic cells
‫تباين الحجم والتعقيد بين الخاليا‬
‫أولية النواة وحقيقة النواة‬
Nucleus ‫نواة‬
(contains DNA surrounded
by nuclear membrane)
)‫(تحتوي على دنا محاط بغالف نووي‬
Organelles ‫عضيات‬
Such diversity of life can be arranged into three domains
‫يمكن ترتيب التنوع الحيوي في ثالثة عوالم‬
• The
3 Domains (Groups) of life are:
:‫• هناك ثالث عوالم ( مجاميع ) حيوية‬
– Domain (Group) Bacteria - prokaryotic, and most are
unicellular and microscopic
‫ وعادة ما تكون وحيدة الخلية و مجهرية‬، ‫البكتيريا – أولية النواة‬
–
– Domain (Group) Archaea - like bacteria - are prokaryotic,
and most are unicellular and microscopic
‫ وعادة ما تكون وحيدة الخلية و مجهرية شأنها شأن‬، ‫البدائيات – أولية النواة‬
‫البكتيريا‬
–
– Domain (Group) Eukarya - are eukaryotic and contain a
nucleus and organelles
‫حقيقيات النواة – خاليا حقيقية النواة أي لها نواة و عضيات‬
–
Domain Bacteria
‫عالم البكتيريا‬
Domain Eukarya ‫عالم حقيقيات النواة‬
Bacteria (multiple kingdoms)
) ‫البكتيريا ( ممالك متعددة‬
Protists (multiple kingdoms)
) ‫األوليات ( ممالك متعددة‬
Kingdom Plantae
‫المملكة النباتية‬
Domain Archaea
‫عالم البدائيات‬
Archaea (multiple kingdoms)
) ‫األركيا ( ممالك متعددة‬
Kingdom Fungi
‫مملكة الفطريات‬
Kingdom Animalia
‫المملكة الحيوانية‬
Organisms interact with their environments,
exchanging matter and energy
• Every organism interacts with its environment,
including other organisms
– For example, a tree takes up water and
minerals from the soil and carbon dioxide from
the air; the tree releases oxygen to the air and
roots help form soil
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Ecosystem Dynamics
• The dynamics of an ecosystem include two
major processes:
– The flow of energy from sunlight to producers
to consumers
– Cycling of nutrients, in which materials
acquired by plants eventually return to the soil
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Living organisms interact with their environments
• Life requires interactions between living and non-living components
–
Photosynthetic organisms provide food and are called
producers
–
Others eat plants (or animals that profit from plants) and are
called consumers
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Sunlight ‫أشعة الشمس‬
Ecosystem ‫نظام بيئي‬
Cycling
of
chemical
Nutrients
‫دورة المواد‬
‫الغذائية الكيميائية‬
Producers
(such as plants)
)‫منتجات (مثل النباتات‬
Heat ‫حرارة‬
Chemical energy
‫طاقة كيميائية‬
Consumers
(such as animals)
)‫مستهلكات (مثل الحيوانات‬
Heat ‫حرارة‬
The cycling of nutrients
and flow of energy
in an ecosystem
‫دورة المواد الغذائية وسريان الطاقة‬
‫في نظام بيئي‬
Energy Conversion
• Energy can be stored in different forms, for
example, light, chemical, kinetic, or thermal
• The energy exchange between an organism
and its environment
• Energy flows through an ecosystem, usually
entering as light and exiting as heat
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
EVOLUTION, THE CORE
THEME OF BIOLOGY
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The continuity of life is based on heritable
information in the form of DNA
• Chromosomes contain most of a cell’s genetic
material in the form of DNA (deoxyribonucleic
acid).
• Each chromosome has one long DNA molecule
with hundreds or thousands of genes
• Make the structures and complex chemicals
necessary for life PROTEINS
• DNA is transcribed into RNA then translated
into a protein
DNA Structure and Function
• DNA in every body cell is exactly alike
• DNA is inherited by offspring from their parents
• DNA controls the development of organisms
• Genes control protein production indirectly
• An organism’s genome is its entire set of
genetic instructions
• Each DNA molecule is made up of two long
chains arranged in a double helix
• Each link of a chain is one of (4) kinds of
chemical building blocks called nucleotides
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
DNA: The genetic material
Inherited DNA directs development of an organism
Sperm cell
Nuclei
containing
DNA
Egg cell
Fertilized egg
with DNA from
both parents
Embryo’s cells with
copies of inherited DNA
Offspring with traits
inherited from
both parents
Diversity of Life
• Approximately 1.8 million species have been
identified and named to date, and thousands
more are identified each year
• Estimates of the total number of species that
actually exist range from 10 million to over 100
million
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Grouping Species: The Basic Idea
• Taxonomy is the branch of biology that names
and classifies species into groups of increasing
breadth
• Domains, followed by kingdoms, are the
broadest units of classification
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Species Genus Family Order
Class Phylum Kingdom Domain
Classifying life
Animalia
Eukarya
Charles Darwin and the Theory of Natural
Selection
• Charles Darwin published on the Origin of
Species by Means of Natural Selection in 1859
• Darwin made (2)main points:
– Species showed evidence of “descent with
modification” from common ancestors
– Natural selection is the mechanism behind
“descent with modification”
• Darwin’s theory explained the duality of unity
and diversity
Darwin observed that:
– Individuals in a population have traits that vary
– Many of these traits are heritable (pass from
parents to sons)
– Competition is necessary
– Species generally suit their environment
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Darwin concluded that:
– Individuals that are best suited to their
environment are more likely to survive and
reproduce
– Over time, more individuals in a population will
have the advantageous traits
• In other words, the natural environment
“selects” for beneficial traits
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1
Population
with varied
inherited traits.
2
Elimination
of individuals
with certain
traits.
3
Reproduction
of survivors.
4
Increasing
frequency
of traits that
enhance
survival and
reproductive
success.
Scientists use two main approaches to learn about
nature
– Discovery science
- uses verifiable observations and measurements to describe
science
– Hypothesis- based science
- uses the data from discovery science to explain science
Discovery Science
• Discovery science : This approach is based
on observation and the analysis of data.
• Data are recorded observations or items of
information, fall into two categories
– Qualitative, or descriptions rather than
measurements
– Quantitative, or recorded measurements,
which are sometimes organized into tables and
graphs
Hypothesis-Based Science
• Observations can lead us to ask questions and
propose hypothetical explanations called
hypotheses
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The Role of Hypotheses in Inquiry
• A hypothesis is a tentative answer to a wellframed question
• A scientific hypothesis leads to predictions that
can be tested by observation or
experimentation
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
• For example,
– Observation: Your flashlight doesn’t work
– Question: Why doesn’t your flashlight work?
– Hypothesis 1: The batteries are dead
– Hypothesis 2: The bulb is burnt out
• Both these hypotheses are testable
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
‫الكشاف الضوئي ال يعمل‬
‫‪Observations‬‬
‫المشاهدة‬
‫لماذا ال يعمل الكشاف الضوئي؟‬
‫‪Question‬‬
‫االستفسار‬
‫‪Hypothesis #2:‬‬
‫‪Burned-out bulb‬‬
‫الفرضية الثانية ‪ :‬المصباح ال يعمل‬
‫‪Prediction:‬‬
‫‪Replacing batteries‬‬
‫‪will fix problem‬‬
‫تكهن ‪ :‬هل تغيير المصباح‬
‫سيحل المشكلة‬
‫‪Test prediction‬‬
‫اختبار التكهن‬
‫‪Test does not falsify hypothesis‬‬
‫االختبار ال يكذب االفتراض‬
‫‪Hypothesis #1:‬‬
‫‪Dead batteries‬‬
‫اإلجابة‬
‫الفرضية االولى ‪ :‬البطارية ال تغمل‬
‫‪Prediction:‬‬
‫‪Replacing batteries‬‬
‫‪will fix problem‬‬
‫تكهن ‪ :‬هل تغيير البطارية‬
‫سيحل المشكلة‬
‫التخمينية‬
‫التكهن‬
‫التجربة‬
‫‪Test prediction‬‬
‫اختبار التكهن‬
‫‪Test falsifies hypothesis‬‬
‫االختبار يكذب االفتراض‬
‫االستنتاج = النظرية‬
Deduction: The “If…Then” Logic of Hypothesis
Based Science
• Deductive reasoning uses general premises
to make specific predictions
• For example, if organisms are made of cells
(premise 1), and humans are organisms
(premise 2), then humans are composed of
cells (deductive prediction)
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
A Closer Look at Hypotheses in Scientific Inquiry
• A hypothesis must be testable and falsifiable
• Hypothesis-based science often makes use of
two or more alternative hypotheses
• Failure to falsify a hypothesis does not prove
that hypothesis
– For example, you replace your flashlight bulb,
and it now works; this supports the hypothesis
that your bulb was burnt out, but does not
prove it (perhaps the first bulb was inserted
incorrectly)
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Theories in Science
• In the context of science, a theory is:
– Broader in scope than a hypothesis
– General, and can lead to new testable
hypotheses
– Supported by a large body of evidence in
comparison to a hypothesis
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings