Modules01-01to01-03

BIOLOGYCONCEPTS & CONNECTIONS

Fourth Edition

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor

From PowerPoint® Lectures for Biology: Concepts & Connections

CHAPTER 1Introduction:

The Scientific Study of Life

Modules 1.1 – 1.3


• 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


• 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

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)

1.1 Life’s levels of organization define the scope of biology


• At the top of life’s hierarchy is the 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


• Organisms are made up of:– organ

systems

– organs

– tissues

– cells

– molecules

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


• In discovery science, scientists describe some aspect of the world and use inductive reasoning to draw general conclusions

– Example: scientists have described how newborn flying foxes cling to their mother’s chest for the first weeks of life

1.2 Scientists use two main approaches to learn about nature

THE PROCESS OF SCIENCE

Figure 1.2


• In hypothesis-driven science, scientists use the “scientific method”– They propose a hypothesis

– They make deductions leading to predictions

– They then test the hypothesis by seeing if the predictions come true


• The main steps of the scientific method

1.3 With the scientific method, we pose and test hypotheses

Observation

Question

Hypothesis

Prediction

Test:Experiment or

additionalobservation

Test does notsupport hypothesis; revise hypothesis or

pose new one

Test supports hypothesis; make

additional predictions and test them

Figure 1.3A


• Deductive reasoning is used in testing hypotheses– If a hypothesis is

correct, and we test it, then we can expect a particular outcome

• Case study: flashlight failure

Figure 1.3B


• Experiments designed to test hypotheses must be controlled experiments

• Control groups must be tested along with experimental groups for the meaning of the results to be clear


• Case study: spider mimicry

Poun

ce ra

te (%

of t

rials

in

whi

ch s

pide

r jum

ped

on fl

y)

Control group(untreated flies)

Experimental group(wing markings masked)

Figure 1.3C

Figure 1.3D


• Another test of the spider mimic hypothesis: wing transplants

Num

ber o

f sta

lk a

ndat

tack

resp

onse

sby

spi

ders

Wingmarkings

Normalspidermimic

Figure 1.3E

Wingwaving

Mimic withmimic wing transplant

Controls Experimentals

Mimic withhousefly

wing transplant

Housefly with

mimic wing transplant

Normalhousefly

Modules01-01to01-03

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