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Lecture Presentations by
Carol R. Anderson
Westwood College, River Oaks Campus
© 2014 Pearson Education, Inc.
BIOLOGY Life on Earth
WITH PHYSIOLOGY Tenth Edition
Audesirk Audesirk Byers
1
An Introduction
to Life on Earth
*modified by Misty Lawrence

Chapter 1 At a Glance
 1.1 What Is Life?
 1.2 What Is Evolution?
 1.3 How Do Scientists Study Life?
 1.4 What Is Science?

1.1 What Is Life?
Biology comes from the Greek words “bio” meaning ―life‖ and
“logy” meaning ―the study of.‖ Organisms share common
characteristics that, taken together, define life. Organisms:







1.1 What Is Life?
 The ________ is the basic unit of life
– It is separated from its surroundings by a membrane
– It encloses a variety of structures and chemicals in a
fluid environment

Figure 1-1 The cell is the smallest unit of life
organelles
nucleus
cell wall
plasma
membrane

1.1 What Is Life?
 Organisms acquire and use materials and energy
– Materials and energy are required for organisms to
maintain organization, to grow, and to reproduce
– Important materials (minerals, water, & other simple
chemical building blocks) are acquired from the air,
water, soil, and bodies of other living things
– Organisms use energy continuously to sustain
themselves

Figure 1-2 Properties of life
Eggs: living
things
reproduce
Gut: living
things acquire
nutrients
Antennae and
eyes: living
things respond
to stimuli

1.1 What Is Life?
 Organisms acquire and use materials and energy
(continued)
– Organisms obtain energy in two ways, coming directly
or indirectly from the sun
– ________________ is the process by which plants and
some single-celled organisms capture sunlight
– Other organisms consume energy-rich molecules in the
bodies of other organisms

Figure 1-3 The flow of energy and the recycling of nutrients

1.1 What Is Life?
 Organisms actively maintain organized complexity
– Living things use energy on a continuous basis to
self-sustain
– Cells pump chemicals in and out for appropriate
chemical reactions to occur
– Organisms maintain relatively constant internal
conditions or _______________-

Figure 1-4 Organisms maintain relatively constant internal conditions
What does your body do to try to maintain
homeostasis when you are physically active?

1.1 What Is Life?
 Organisms perceive and respond to stimuli
– Organisms sense and respond to internal and
external environmental stimuli
– Sensory organs in animals can detect and respond to
external stimuli such as light, sound, chemicals, etc.
– Internal stimuli in animals are perceived by stretch,
temperature, pain, and chemical receptors
– Plants and bacteria respond to stimuli as well (e.g.,
plants grow toward the light, and bacteria move toward
available nutrients in a medium)

1.1 What Is Life?
 Organisms grow
– Every organism becomes larger over time
– Plants, birds, and mammals grow by producing more
cells to increase their mass
– Bacteria grow by enlarging their cells; they divide in
half to reproduce after genetic material is copied
– Growth involves the conversion of acquired materials
to molecules of the organism’s body

1.1 What Is Life?
 Organisms reproduce
– Organisms reproduce by:
–
–
–
–
– Organisms give rise to offspring of the same type
– The parent’s genetic material (___) is passed on to
the offspring, creating continuity of life

Figure 1-6 Organisms reproduce
Dividing Streptococcus
bacterium
Panda with its babyDandelion producing
seeds

1.1 What Is Life?
 Organisms, collectively, have the capacity to evolve
– Evolution is the process by which modern organisms
descended, with modifications, from preexisting forms
of life
– Changes in DNA within populations occur over the
course of generations, which results in evolution
– Populations are

1.2 What Is Evolution?
 Evolution explains the diversity of life on Earth
 Evolution provides an explanation for the similarities
found among different types of organisms
– Chimpanzees and people have various physical
features in common
– DNA of humans differs from that of chimpanzees by
less than 5%

Figure 1-8 Chimps and people are closely related

 Three natural processes underlie evolution
–
–
–

 Mutations are the original source of differences in
DNA
– Variations are due to the differences in genes, which
are components of DNA and the basic units of
heredity
– ___________ occur when changes in genes are
mistakenly copied
– Mutations can also result from DNA damaged by
– UV rays from sunlight and toxic chemicals

 Some mutations are inherited
– Occur in sperm or egg cells
– Effects of mutation
– No effect (harmless)
– A decrease in the organism’s ability to function
– Death of the organism
– An increase in an organism’s ability to survive and
reproduce (rare)

 Some inherited mutations help individuals survive
and reproduce
– ________ ________is the process by which
organisms with certain inherited traits survive and
reproduce better than others in a particular
environment
– Organisms that best meet environmental challenges
leave the most offspring
– Natural selection preserves genes that help organisms
flourish

 Some inherited mutations help individuals survive
and reproduce (continued)
– Adaptations are structures, physiological processes,
or behaviors that aid in survival and reproduction
– Adaptations that are good for one environment may
be poor in another (Can you give an example?)
– Species that cannot adapt to environmental change
become extinct, as for example, the dinosaurs
– Extinction is the

Levels of biological organization
Fig. 1-10

1.3 How Do Scientists Study Life?
 Life can be studied at different levels
– All matter is formed of elements
– An atom is the smallest _____ _____ _____ retaining
the properties of an element
– Atoms combine to form molecules
– Molecules provide the building blocks for cells, the
smallest _______ ___ ______

 Life can be studied at different levels (continued)
– Some forms of life consist of single cells
– In multicellular forms, cells combine to form tissues
– Tissues combine to form organs, which can be united
as organ systems
– Multicellular organisms are composed of multiple
organ systems

 Life can be studied at different levels (continued)
– Organisms of the same type that are capable of
interacting and interbreeding are called a species
– A group of organisms of the same species living in a
given area is a population
– Interacting populations make up a community
– A community and its nonliving environment is an
ecosystem
– The entire surface of Earth, including living and
nonliving components, is the biosphere

 Biologists classify organisms based on their
evolutionary relationships
– Scientists generally categorize organisms into three
major groups, or domains
–
–
–
– The fundamental differences among cell types in
organisms are reflected in classifications

Figure 1-11 The domains and kingdoms of life
FIRST CELLS
DOMAINBACTERIA
Protists
DOMAINEUKARYADOMAINARCHAEA
Plants
Fungi
Animals

 Biologists classify organisms based on their evolutionary
relationships (continued)
– Bacteria and Archaea are single, simple cells
– Eukaryotic organisms have one or more extremely
complex cells
– The domain Eukarya contains four subdivisions or kingdoms
–
–
–
–

 Biologists classify organisms based on their evolutionary
relationships (continued)
– There are exceptions to any simple set of rules used to
distinguish the domains and kingdoms, but three
characteristics are particularly useful
– Cell type—simple or complex
– The number of cells in each organism—unicellular or
multicellular
– Energy acquisition

Table 1-1

 Cell type distinguishes the Bacteria and Archaea
from the Eukarya
–All cells share common features
– Plasma membrane is a thin sheet of molecules
surrounding the cell
– Organelles are specialized structures that carry out
specific functions
– All cells contain DNA, the hereditary material

from the Eukarya (continued)
– The domains Bacteria and Archaea consist of
_______________ cells
– The domain Eukarya is composed of ____________
cells

– Two cell types are seen among all living things:
prokaryotic and eukaryotic cells
– Cell types are named after presence or absence of a
nucleus
– The nucleus is a membrane-enclosed sac containing
the cell’s genetic material

– Eukaryotic (―true nucleus‖ in Greek)
– They are larger than prokaryotic cells
– They contain a variety of organelles, including a
nucleus
– This cell type is found only among members of the
domain Eukarya
– They are extremely complex

– Prokaryotic (―before nucleus‖ in Greek)
– They are only 1–2 micrometers in diameter
– They lack organelles enclosed by membranes
– They lack a nucleus
– This cell type is found in the domains Bacteria and
Archaea
– They are smaller and much simpler than the eukaryotic
cell

 Multicellularity occurs only among the Eukarya
– Unicellular (single-celled) organisms are found in
– Bacteria
– Archaea
– Multicellular (many-celled) organisms are found in
Eukarya, within the kingdoms
– Fungi
– Plantae
– Animalia

 The Eukarya acquire energy in different ways
– Autotrophs (―self-feeding‖)
– Photosynthetic organisms that capture sunlight and store it
in sugar and fats
– Includes plants, some bacteria, and some protists
– Heterotrophs (―other-feeding‖)
– Organisms that acquire energy through ingesting molecules
in the bodies of other organisms
– Includes many archaeans, bacteria, protists, fungi, and
animals
– The size of the food eaten varies from individual food
molecules to ingestion and digestion of whole chunks

 Biologists use the binomial system to name
organisms
– Organisms are placed in a hierarchy of categories
– Genus and species are the two smallest categories
– Genus includes many different species with similar
characteristics
– Species includes organisms that can interbreed and are
nearly identical

 Biologists use the binomial system to name
organisms (continued)
– Binomial system based on Latin words two (bi) and
names (nomial), and consisting of the genus and
species
– Genus name is capitalized
– Both genus and species names are italicized
– People are ______ __________

1.4 What Is Science?
 Science is the systematic inquiry – through
observation and experiment – into the origins,
structure, and behavior of living and nonliving
environments

 Science is based on the principle that all events
have natural causes
– The belief that some events happen through
supernatural forces (e.g., the actions of Greek gods)
– The belief that all events can be traced to natural
causes that we can comprehend (natural causality)
– Corollary: Evidence gathered from nature has not been
deliberately distorted to fool us

 The scientific method is an important tool of
scientific inquiry
 Scientific inquiry is a rigorous method for making
observations
– The scientific method for inquiry follows six steps

 The six steps of scientific inquiry
1. Observation of a specific phenomenon
2. The observation, in turn, leads to a question
3. The question leads to formulation of a hypothesis,
based on previous observations, which is offered as
an answer to the question

 The six steps of scientific inquiry (continued)
4. The hypothesis leads to a prediction, which is
the expected outcome of testing if the hypothesis is
correct
5. The prediction is tested by carefully designed
additional observations or carefully controlled
manipulations called experiments
6. The experiments produce results that either support
or refute the hypothesis, allowing the development
of a conclusion

 Biologists test hypotheses using controlled experiments
– Two types of situations are established
– A baseline or control situation in which all possible
variables are held at a constant
– An experimental situation in which one factor, variable, is
manipulated to test the hypothesis to determine that
this variable is the cause of an observation
– Science is useless unless communicated
– The scientific method is illustrated by experiments by
Francesco Redi and Malte Andersson

 Scientific theories have been thoroughly tested
– A scientific theory is a general and reliable
explanation of important natural phenomena that has
been developed through extensive and reproducible
observations and experiments
– A scientific theory is best described as a natural law,
a basic principle derived from the study of nature,
which has never been disproven by scientific inquiry

(continued)
– The cell theory (that all living organisms are
composed of cells) and the theory of evolution are
fundamental to the study of biology
– Natural causality is the principle that all events can be
traced to natural causes
– Natural laws apply to every time and place
– Scientific inquiry is based on the assumption that
people perceive natural events in similar ways

(continued)
– New scientific evidence may prompt radical revision
of existing theory
– For example, the discovery of prions

 Scientific theories involve both inductive and
deductive reasoning
– Inductive reasoning is used in the development of
scientific theories
– A generalization is created from many observations
that support it and none that contradict it
– For example, the theory that Earth exerts gravitational
forces on objects began from repeated observations of
objects falling downward toward Earth and from no
observations of objects falling upward away from Earth

 Scientific theories involve both inductive and
deductive reasoning (continued)
– Deductive reasoning is the process of generating
hypotheses based on a well-supported generalization
(such as a theory)
– For example, based on the cell theory, any newly
discovered organism would be expected to be
composed of cells

 Scientific theories are formulated in ways that can
potentially be disproved
– Basic principles of science are referred to as theories
because theories can be disproved or falsified
– Falsifying theories is distinctly different between
scientific theories and faith-based beliefs
– ―Each creature on Earth was separately created‖
cannot be subjected to scientific inquiry because it is a
belief rooted in faith

 Science is a human endeavor
– Human personality traits are part of ―real science‖
– Scientists, like other people, may be driven by pride,
ambition, or fear
– Scientists sometimes make mistakes
– Accidents, lucky guesses, intellectual powers, and
controversies with others contribute strongly to
scientific advances

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