• 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

Flying foxes are becoming an endangered species, partly

because of habitat destruction

• Biology is the scientific study of life

• Interactions between different kinds of organisms affect the lives of all– Recall the example of flying foxes and

eucalyptus trees

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

• At the top of life’s hierarchy is the ecosystem ECOSYSTEM LEVEL

Eucalyptus 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

Figure 1.1

• Ecosystems include:– all the organisms in

an area, which make up a community

– interbreeding organisms of the same species, a population

• 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)

• The theory of natural selection applies to all levels in life’s hierarchy

• In an ecosystem, these interactions make up a complex web of relationships– The functional aspects of an ecosystem come

from the structure of the ecosystem’s web

• A web of interactions in a rain forest ecosystem

Plants, or plant products, are the ultimate sources of food in an

ecosystem– This African sunbird is consuming nectar, a plant

product

– Energy flows in and out constantly

Figure 1.7C

Sun

Inflowof

lightenergy

Air Chemicalenergy

Cyclingof

chemicalnutrientsOrganisms

SoilECOSYSTEM

• Chemical nutrients cycle within an ecosystem’s web

• Biology is connected to a great number of important issues– Environmental

problems and solutions

– Genetic engineering– Medicine

Figure 1.8A

• Evaluating everyday reports in the press about a large range of subjects requires critical thinking and some familiarity with many areas of biology– In order to understand

how rain forest destruction impacts global climate, it is important to understand biology from the molecular to the ecosystem level

• Many technological advances stem from the scientific study of life

• Grouping organisms by fundamental features helps make the vast diversity of life manageable for study

• Scientists classify organisms into a hierarchy of broader and broader groups

Figure 1.4A, B

• Most classification schemes group organisms into three domains:

–Domain Bacteria

Domain Archaea

Domain Eukarya

• 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

DNA is made of chemical units called nucleotides

• Each species has its own nucleotide sequence

• 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

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

• 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

Chapter 1 Vocabulary

• Adaptation• Biology• Development• Energy• Environment• Evolution• Growth

• Homeostasis• Organism• Organization• Reproduction• Response• Species• Stimulus