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Introduction to Biology Lecture 1. Much of the text material in the lecture notes is from our textbook, “Essential Biology with Physiology” by Neil A. Campbell, Jane B. Reece, and Eric J. Simon (2004 and 2008). I don’t claim authorship. Other sources were sometimes used, and are noted. Outline.

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Introduction to biology lecture 1

Introduction to BiologyLecture 1

Introduction to biology lecture 1

Much of the text material in the lecture notes is from our textbook, “Essential Biology with Physiology” by Neil A. Campbell, Jane B. Reece, and Eric J. Simon (2004 and 2008). I don’t claim authorship. Other sources were sometimes used, and are noted.



  • Life sciences—a few current areas

  • Approaches to understanding life

  • The beginning of our journey

  • Ecology and ecosystems

  • Cells and their DNA

  • The diversity of life

  • Natural selection and evolution

  • The processes and culture of science

  • Words and terms to know

  • Possible test items

A few current areas

A Few Current Areas

  • Ecosystems and ecology

  • Human genome project

  • Reproductive and therapeutic cloning

  • DNA fingerprinting for legal purposes

  • Nutrition and physical activity

  • Medicines derived from plants

  • Human development and aging

  • Neurosciences and behavior

  • Infectious disease spread

  • Aircraft and spacecraft design

  • Understanding of the origin of life

  • Are we alone in the universe?

Human genome project

  • The entire set of genetic instructions an organism inherits is called its genome.

  • A human genome map was published in 2001 after several years of work at many laboratories.

  • The map gives biologists a powerful tool to explore the functions of thousands of genes.

  • Genome have many applications in the biological and medical sciences such as the early identification of genetic diseases and the production of new pharmaceutical drugs.

Human Genome Project

Introduction to biology lecture 1

  • Each person has a unique DNA ‘fingerprint’ based on genetic material common to each of the trillions of cells in the human body.

  • DNA patterns are more similar—the closer people are genetically related to each other.

  • The probability that two or more people have an identical DNA fingerprint is very small.

  • DNA fingerprinting has been used to obtain criminal convictions and exonerations, and establish identity and paternity.

DNA Fingerprinting

Nutrition and physical activity

  • Good nutrition and physical activity are critical to child development, and life-long healthy living.

  • They are critical to weight management (obesity and overweight rates are very high in the United States).

  • They can also help in disease prevention (for example, two-thirds of cancer cases are related to lifestyle choices).

Nutrition and Physical Activity

Introduction to biology lecture 1

Medicines Derived From Plants

Periwinkle, Madagascar

Vinblastine is used in some leukemia drugs.

Eucalyptus, Australia

Menthol is an ingredient in some cough medicines.

Introduction to biology lecture 1

Medicines Derived from Plants

Belladonna, Europe, western Asia, Africa, and North America

Atropine is used as an pupil dilator in eye exams.

Pacific Yew, Pacific Northwest and British Columbia

Taxol is an ovarian cancer drug.

Aircraft design

The design of the B-2 aircraft included life support, ozone effects, rapid decompression effects, ejection systems and survivability, NBC protection, acoustic noise cancellation, workload assessment, physical and mental fatigue, anthropometry, visual and acoustic processing, situational awareness, vibration effects, and biodynamic modeling.

Aircraft Design

Introduction to biology lecture 1

First Steps Beyond Our Planet

Ed White, first U.S. spacewalk, Gemini program, 1965

Bioastronomy and seti

Andromeda Galaxy (M31)


With billions of stars in a galaxy and billions of galaxies in our universe,

is life unique to our planet?

Bioastronomy and SETI

Introduction to biology lecture 1

Understanding Life

Science, Philosophy, Theology, Art

Public domain

Paul Gauguin, Where Do We Come From? Where Are We Going To? (1897-98)

This course is based on the scientific method—I’m not sufficiently knowledgeable to teach other approaches.

Introduction to biology lecture 1

Our Journey Begins Here

We will soon get started…

Human brain—the left cerebral hemisphere, cerebellum, and brainstem are visible.

Introduction to biology lecture 1

… And Here

  • A neuron has one axon, some as long as one meter, and typically many more dendrites than shown here.

  • The human brain has over 10 billion neurons, each with potentially thousands of connections known as synapses.

  • Neurons are the basic cellular unit of informa-tion processing.

  • Much research is being performed on neurons and their synaptic connections as they relate to:

    • Sensations and perceptions

    • Thoughts and emotions

    • Fine motor skills and other motor actions

    • Sleep and altered states of consciousness

    • Neurological and other medical conditions

An artist’s conception

Introduction to biology lecture 1


  • Life does not exist in a vacuum—all life forms interact continuously with other living organisms and non-living components in their environments.

  • Consider plants:

    • Roots absorb water (H20) and minerals from the soil.

    • Fungi (mycorrhizae) help the roots absorb nitrogen from the soil.

    • Leaves absorb carbon dioxide (CO2) from the air.

    • Chloroplasts absorb sunlight and produce sugars from H20 and CO2.

    • Leaves release oxygen (O2) into the air.

    • Roots break-up rocks to help form soil to promote more plant growth.

Introduction to biology lecture 1


Fungi living in mutual association with roots are essential to many plants.

Introduction to biology lecture 1


  • Ecology is the biological study of the relationship between organisms and their environments.

  • As a scientific discipline, ecology helps us understand the impact of human activities on our planet.

Introduction to biology lecture 1


  • An ecosystem refers to all organisms and nonliving factors affecting life in an specific area.

  • Southern California’s ecosystems includes:

    • Foothills and mountains

    • High and low deserts

    • Rivers, streams, and lakes

    • Marshes, estuaries, and other wetlands

    • Channel Islands and Pacific Ocean

Introduction to biology lecture 1


  • The dynamics of a ecosystem depend on:

    • Cycling and recycling of nutrients

    • The flow of energy from sunlight to food producers, and then to consumers

  • The biosphere is the sum of the dynamic processes in all ecosystems on our planet.

Introduction to biology lecture 1


Kelp forest

  • The kelp forests off our coast are one of many ecosystems in Southern California.

  • Kelp is rich in nutrients such as plankton.

  • The underwater forest provides food and protection to many fish and other marine species.

  • Biologists study marine life to understand each species and interdependence among species in the oceans.

Kelp Forest

Introduction to biology lecture 1

Eaton Canyon Falls

Near Altadena, California

Introduction to biology lecture 1

Bolsa Chica Wetlands

Just south of Seal Beach, California.

Introduction to biology lecture 1

Life’s Basic Unit

  • Cells are the lowest level of structure that can perform all activities of life.

  • All life is composed of cells.

  • Many forms of life are single-cell organisms such as bacteria, amoeba, and protozoa.

  • Plants and animals are composed of many cells (trillions in humans).

  • The ability of cells to divide is the basis of reproduction, and for growth and repair of multi-cellular organisms.

  • All cells use DNA for transmitting information from parents to offspring.

Introduction to biology lecture 1

Cell Types

Prokaryotic cell


Eukaryotic cell

Plants, animals, and fungi (animal cell shown)

Not to scale: A prokaryotic cell is about 1000 times smaller in volume than a eukaryotic cell.

Introduction to biology lecture 1


  • DNA is found in the nuclei of eukaryotic cells, and central region of prokaryotic cells.

  • DNA consists of four chemical ‘letters’ (A, G, C, and T).

  • Human DNA contains about 3.2 billion chemical letters.

  • DNA is the universal genetic language that serves as the chemical material of genes.

  • Genes are units of inheritance that transmit information from parents to offspring.

Double helix

Introduction to biology lecture 1

Diversity of Life

  • Biological diversity can be overwhelming with so many plants and animal species.

  • Species are grouped into smaller numbers of groups to aid in comparison of similarities and differences.

  • Taxonomy is a branch of biology that names and classifies species into a hierarchical ordering.

Introduction to biology lecture 1

Domains and Kingdoms

  • For now, we consider only domains and kingdoms, the broadest units of classification.

  • New methods such as comparative analysis of DNA have led to ongoing reassessment of the number of kingdoms.

  • Although debate continues, the general consensus is that the kingdoms belong to three domains of life.

Introduction to biology lecture 1

Course Focus


Green represents the primary focus of this course







Three domains

of life









Four kingdoms

of eukarya

The domains bacteria and archaea consist of prokaryotic cells; the domain eukarya consists of eukaryotic cells

Introduction to biology lecture 1

History of Life

  • The history of life on our planet, which is about 4.5 billion years old, is a changing cast of life forms.

  • Each species that exists now is one ‘twig’ on a branching tree extending to earlier species and a more remote time.

  • Similar species sharing a common ancestor represent a recent branch point (for example, brown bears and polar bears).

  • Less similar species, for example, represent a branch point further back in time (for example, bears and squirrels).

Introduction to biology lecture 1


  • Mammals, birds, reptiles share a common ancestor even further back in time.

  • Evidence of this interconnectedness can be found in cell features, DNA, and anatomy.

  • All life is connected, and the basis for this kinship is known as evolution.

Introduction to biology lecture 1

H.M.S. Beagle

Public domain

Exploration of Tierra Del Fuego

Introduction to biology lecture 1

Voyage of Discovery

  • As a young man, Charles Darwin was invited to be the ship’s naturalist on a hydrographic survey of South America.

  • The around-the-world expedition lasted almost five years, from 1831 to 1836.

  • Darwin spent 18 months at sea and over three years on land, much of it in South America.

  • He kept detailed notes and collected many animal and plant species that were shipped home to England.

  • Darwin had time to read including books some that anticipated aspects of the theory of evolution.

Introduction to biology lecture 1

Then and Now

Queen Mary 2, 2006

H.M.S. Beagle, 1831

Both ships have circumnavigated the globe, but only one journey led to a profound change in science and worldview.

Introduction to biology lecture 1


  • Although Darwin spent just six weeks in the Galapagos Islands, his visit would change biological thinking.

  • In 1859, Darwin published “On the Origin of the Species” his first work on natural selection and evolution.

Darwin’s later microscope that he used to study plant and barnacle specimens.

Introduction to biology lecture 1

Environmental Adaptation

  • Darwin regarded adaptation to the environment and origin of new species as closely related processes.

  • For example, populations of a species separated by a geographical barrier diverge in appearance over many generations as they adapt to different local conditions.

  • Finches arrived in the Galapagos Islands from South America 2-3 million years ago.

  • Fourteen finch species were found on individual islands in the island chain.

  • Darwin noted major differences in beak structures.

  • The beaks evolved as adaptations to the types of foods available on each island.

Introduction to biology lecture 1

Finch Beaks

Public domain

Finches in the Galapagos Islands have vastly varying beaks.

Introduction to biology lecture 1

Darwin’s Finches

Small tree finch

Medium tree finch

Large tree finch

Mangrove finch

Woodpecker finch

Large ground finch

Medium ground finch

Small ground finch

Large cactus ground finch

Cactus ground finch

Vegetarian finch

Thin beak

Large, powerful beak






Green warbler finch

Gray warbler finch

Thin beak

Sharp-beaked ground finch

Ground Finches

Tree Finches

Warbler Finches

Common Ancestor,

South American


Introduction to biology lecture 1

Natural Selection

  • Natural selection is based on two principals and a conclusion

  • Principal 1: Overproduction and struggle for existence—any population of a species can produce many more offspring than the environment can support.

  • Principal 2: Individual variation—individuals in a population vary in heritable traits, and no two individuals are exactly alike.

  • Conclusion: Unequal reproductive success—in the struggle for existence individuals with traits best adapted to the environment will have the greatest reproductive success.

  • Traits that enhance survival and reproduction will be more highly represented in the next generations.

Introduction to biology lecture 1

Meet the Beetles

2. Birds eliminate individual

beetles (usually white shells)

1. Beetle population has a specific

inherited trait (white or dark gray shells)




These imaginary beetles typically

live on a dark-colored tree bark

4. Traits that enhance survival and

reproductive success predominate

3. The survivors reproduce

Introduction to biology lecture 1

Descriptive Science

  • Science seeks natural causes for natural phenomena based on observation and measurement.

  • Science cannot prove or disprove the existence of the supernatural and if they have any effect on natural phenomena.

  • The goal of descriptive, or discovery, science is to understand the structure of nature.

  • Darwin’s study of the plants and animals on the Beagle was descriptive science.

  • Descriptive science can lead to important conclusions based on inductive reasoning.

Introduction to biology lecture 1

Inductive Reasoning

  • Inductive reasoning flows in the direction of specifics to the general, or from observations to conclusions.

  • A conclusion is a generalization summarizing many observations, such as “all organisms consist of cells.”

  • Inductive reasoning has played an important in the accumulation of biology knowledge.

Introduction to biology lecture 1


A scientist’s sketch of diatoms.

Introduction to biology lecture 1

Hypothesis-Based Science

  • Hypothesis-based science is based on deductive reasoning that flows from the general to the specific.

  • Results (predictions) are extrapolated if the premises are found to be true.

  • Premise 1: If all organisms are made of cells

  • Premise 2: And humans are living organisms

  • Deductive prediction: Then humans are composed of cells

  • The approach is known as hypothesis testing, the cornerstone of scientific experimentation.

Introduction to biology lecture 1

Hypothesis Testing





Test supports hypothesis;

make additional predictions

and test them.

Test does not support hypothesis;

revise or reject hypothesis, or

develop a new one.


(Experiment or study)

Introduction to biology lecture 1

A Tale of Two Snakes

Eastern Coral Snake

Scarlet Kingsnake

Both species of snake live in the eastern Carolinas

Introduction to biology lecture 1


  • Observation: The venomous eastern coral snakes and non-venomous scarlet kingsnake both have red, yellow, and black rings.

  • Question: Why do scarlet kingsnakes look similar to eastern coral snakes?

  • Hypothesis: Mimicry helps protect scarlet kingsnakes from predators.

  • Prediction: Predators will confuse scarlet kingsnakes with eastern coral snakes.

  • Test: Compare the number of animal attacks on ringed versus brown artificial snakes.

  • Test outcome: The brown artificial snakes are attacked by birds and other animals about five times more often than ringed artificial snakes.

Introduction to biology lecture 1


Details of the experiment are described in the textbook.



Percentage of Total Attacks




Artificial Snakes

In Plain Brown

Artificial Snakes

With Colored Rings

Introduction to biology lecture 1

Culture of Science

  • Science is dependent on observations and measurements.

  • Ideas or hypotheses are testable by experiments that others can repeat.

  • Scientists focus on evidence, and often have a high level of inquiry and skepticism.

  • Information is shared in many ways including in meetings, publications, and the internet.

  • This sharing contributes to the progressive and self-correcting qualities of science.

  • The theories that scientists develop consolidate observations and have predictive power.

Introduction to biology lecture 1

Science Is International

  • Basic science is international, and often knows no political boundaries.

  • Some of the giants of science are:

    • Isaac Newton, Great Britain

    • Charles Darwin, Great Britain

    • Ramón y Cajal, Spain

    • Marie Curie, Poland and France

    • Albert Einstein, Germany and United States

Galileo Galilei,


Public domain

Introduction to biology lecture 1

Words and Terms to Know

  • Genome

  • Hypothesis testing

  • Inductive reasoning

  • Kingdoms

  • Natural selection

  • Organism

  • Prokaryotic cell

  • Biosphere

  • Deductive reasoning

  • DNA

  • Domains of life

  • Ecology

  • Ecosystem

  • Eukaryotic cell

  • Evolution

Introduction to biology lecture 1

Possible Test Items

  • Describe two current areas of general interest in the life sciences.

  • How can ecology help us understand the interconnectedness of our world?

  • What are the characteristics of an ecosystem? Describe an ecosystem you visited.

  • Describe the basic elements of adaptation and natural selection, and give an example.

  • Describe two differences between inductive reasoning and deductive reasoning.

  • Outline an experiment to answer a simple question of your choosing.

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