Unit1 Lecture1

BIO 3

Introduction to Biology

Instructor: Francisca Herrera

Course Syllabus Course Requirements

Exams Unit Reviews Journals Forums

What is a living thing? What are the characteristics of life?

Living organisms are a carbon- and water-based cellular form with complex organization and heritable genetic information.

They undergo metabolism, possess a capacity to grow, respond to stimuli, reproduce, and, through natural selection, adapt to their environment in successive generations.

Properties of life

Living organisms are: a carbon- and water-based cellular form

Cell Theory Cells are basic structural and physiological units of all

living organisms Cells are both distinct entities and building block of

more complex organisms

Properties of life

Living organisms:undergo metabolism

Require Energy Cells use nutrients to supply energy

and build new structures Metabolism: the sum total of chemical

reactions that occur in an organism

Figure 1.2 Acquiring nutrient material and energy

Properties of life

Living organisms:respond to stimuli

Respond helps ensure the survival of an organism allows an organism to carry on daily activities

Properties of life

Living organisms:possess a capacity to grow…

reproduce

Reproduce and Develop: asexual reproduction (clonal):

produce exact replica of themselves

sexual reproduction (many strategies): exchange of genetic material between organisms

Figure 1.3 A Human Family

Properties of life

Living organisms have:heritable genetic information… through

natural selection, adapt to their environment

Heredity genome – all DNA molecules in a cell adaptation – an organism’s modification in structure,

function, or behavior suitable to the environment

Properties of life

Living organisms have:complex organization

Life Science biology is the scientific study of life

Life is complex! There are levels of life:

Figure 1.1 Levels of biological organization

SmallMolecules

LargeMolecules

Cells Tissues Organs OrganSystems

ComplexOrganisms

AnimalsFungiPlantsProtistsArchaeaBacteria0

1.0

2.0

3.0

4.0

0.5

1.5

2.5

3.5Bill

ions

of Y

ears

Ago

(BYA

)

BACTERIA

ARCHAEAEUKARYA

Life is complex! There is diversity of life:

Figure 1.4 Evolutionary tree

Figure 1.6 Domain Bacteria

Figure 1.5 Domain Archaea

• Prokaryotes: single-celled organisms

• Eukaryotes: multi-celled organisms

Figure 1.8 Kingdom Fungi

Figure 1.9 Kingdom Plantae

Figure 1.10 Kingdom Animalia

Figure 1.7 Kingdom Protista

Life is complex! There is taxonomic

order to life:

Life is complex! There is ecological

order to life:

Life is complex! Life is interconnected

and interdependent:

Heat

Heat

Heat

Che

mic

als

Che

mic

als

Decomposers

Consumers

Producers

Solarenergy

Figure 1.12 A grassland, a terrestrial ecosystem

The scientific process To understand such a

complex subject, scientists developed the scientific method: allows scientists to modify and

correct their beliefs as new observations and information becomes available

if well supported > theory!

Core Ideas of Biology A theory is a unifying explanation that has

been well supported time and time again. There are four major unifying themes in the

study of life.

Core Ideas of Biology

The Cell Theory: All organisms are composed of cells All cells come from other cells

Robert Hooke – named cells Anton van Leeuwenhoek –

“wee animalcules”

Core Ideas of Biology

The Gene Theory: All organisms have a genome An organism’s genes determine

what it will be like (secret code!)

James Watson and Francis Crick –

discovered DNA structure

Core Ideas of BiologyThe Theory of Heredity: The genes of any organism

are inherited as discrete units

Those genes are packaged up in chromosomes

Gregor Mendel – Mendelian segregation

Core Ideas of BiologyThe Theory of Evolution: Organisms that can respond to

the challenges of living will leave more offspring

Descent with modification!

Charles Darwin – living organisms are related to one another

Today’s Journal Entry Under the activities menu of the virtual

classroom, click on the Journals link Topic 1 – Introduction to Biology

There are no wrong answers in the journal entries.

Answer in complete sentences, in a clear and concise manner.