Created by Roxanne LeitnerNeil A. Campbell • Brad Williamson • Robin J. Heyden

CONCEPT 1.1 Biology explores life from the global to the microscopic scale.

Objectives

• Identify the major organizational levels of life.

CONCEPT 1.1 Biology explores life from the global to the microscopic scale.

Key Terms

• biosphere

• ecosystem

• organism

• cell

• DNA

• gene

Biosphere

• all parts of the planet that are inhabited by living things• atmosphere

• lithosphere

• hydrosphere

• Flying foxes are becoming an endangered species, partly because of habitat destruction

• The lives of gray-headed flying foxes are closely entwined with the lives of the eucalyptus trees that form their habitat

• Eucalyptus trees provide food and roosting sites for the flying foxes

• Flying foxes aid in eucalyptus pollinationand help disperse the resulting seeds

Life in the Trees

• Biology is the scientific study of life

• Interactions between different kinds of organisms affect the lives of all

The Scope of Biology

• A structural hierarchy of life, from molecules to ecosystems, defines the scope of biology

• An ecosystem consists of:

• all organisms living in a particular area

• all nonliving physical components of the environment that affect the organisms (soil, water)

Life’s levels of organization define the scope of biology

Ecosystem

• Ecosystems include:

• all the organisms in an area, which make up a community

• interbreeding organisms of the same species, a population

ECOSYSTEM LEVELEucalyptus forest

COMMUNITY LEVELAll organisms ineucalyptus forest

POPULATION LEVELGroup of flying foxes

ORGANISM LEVELFlying fox

ORGAN SYSTEM LEVELNervous system

ORGAN LEVELBrain

Brain Spinal cord

Nerve

TISSUE LEVELNervous

tissue

CELLULAR LEVELNerve cell

MOLECULAR LEVELMolecule of DNA

Figure 1.1

Organism

• Organisms are made up of:

• organ systems

• organs

• tissues

• cells

• molecules

• atoms

ECOSYSTEM LEVELEucalyptus forest

COMMUNITY LEVELAll organisms ineucalyptus forest

POPULATION LEVELGroup of flying foxes

ORGANISM LEVELFlying fox

ORGAN SYSTEM LEVELNervous system

ORGAN LEVELBrain

Brain Spinal cord

Nerve

TISSUE LEVELNervous

tissue

CELLULAR LEVELNerve cell

MOLECULAR LEVELMolecule of DNA

Figure 1.1

Concept Check 1.1

1. Which level of life includes all of the other levels in this list: organisms, cells, biosphere, molecules, ecosystems? Explain your answer.

biosphere

2. Identify an ecosystem in the area where you live?

Concept Check 1.1

3. What are genes? How are they related to DNA?

genes – units of inherited information

part of DNA molecule

CONCEPT 1.2 Biology explores life in its diverse forms.

Objectives

• Use the term species in discussing life’s diversity.

• Explain the basic strategy biologists use in classifying organisms.

• Identify a characteristic that separates the domains Bacteria and Archaea from the domain Eukarya.

CONCEPT 1.2 Biology explores life in its diverse forms.

Key Terms

• species

• domain

• unicellular

• prokaryotic cell

• eukaryotic cell

• multicellular

Classifying Life: The Basic Idea

taxonomy

• study of classification

species

• organisms that look alike, can interbreed & produce fertile offspring

Levels of Classification

• Kingdom

• Phylum

• Class

• Order

• Family

• Genus

• Species

Three Domains

• unicellular

• prokaryotic cells – without nuclei or membrane-bound organelles

1. Domain Bacteria• Typical bacteria

Figure 1.4A, B

2. Domain Archaea• live in harsh environments

Figure 1.4C-F

3. Domain Eukarya

• unicellular or multicellular

• eukaryotic cells• nucleus

• membrane-bound organelles

• Kingdoms• Protista

• Fungi

• Plantae

• Animalia

Concept Check 1.2

1. Explain the relationship between the terms species and organism.

2. Explain two different ways that you could classify the following items: banana, lemon, sandwich, milk, orange, meatball, salad.

Concept Check 1.2

3. Explain the main difference between organisms of the domains Bacteria and Archaea and organisms of the domain Eukarya.

Bacteria, Eukarya – prokaryotes

Eukarya - eukaryotes

CONCEPT 1.3 Ten Themes unify the study of life.

Objectives

• Identify the themes of biology.

CONCEPT 1.3 Ten Themes unify the study of life.

Key Terms

• systems

• photosystem

• producer

• consumer

• homeostasis

• adaptation

• population

• natural selection

• evolution

• All organisms share a set of common features, signs of unity in life’s vast diversity

• All are made of cells

• All have DNA as their genetic blueprint

• These orchids show the variety possible within one species

Unity in diversity: All forms of life have common features

Figure 1.5A

• DNA is made of chemical units called nucleotides

• Each species has its own nucleotide sequence

Figure 1.5B

• The genetic information in DNA underlies all of the features that distinguish life from nonlife

• Order and regulation

• Growth and development

• Use of energy from the environment

• Response to environmental stimuli

• Ability to reproduce

• Evolutionary change

• Charles Darwin is a central figure in biology

• He synthesized the theory of evolution by natural selection

• A theory in science is a comprehensive idea with broad explanatory power

• Evolution is the core theme of biology

Evolution explains the unity and diversity of life

Figure 1.6A

Natural Selection

• The theory of natural selection explains the main mechanism whereby all species of organisms change, or evolve

Figure 1.6B

(1) Population with varied inherited traits

(2) Elimination of individuals with certain traits

(3) Reproduction of survivors

• Evolution happens when populations of organisms with inherited variations are exposed to environmental factors that favor the success of some individuals over others

• Natural selection is the editing mechanism

• Evolution is based on adaptations

Concept Check 1.3

1. Using examples describe three biology themes.

2. Describe four ways you have interacted with your environment today.

Concept Check 1.3

3. In biological terms are you a producer or consumer? Explain your answer.