01 lectures ppt

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

PowerPoint Lectures for Biology, Seventh Edition

Neil Campbell and Jane Reece

Lectures by Chris Romero

Chapter 1

Exploring Life


• Overview: Biology’s Most Exciting Era

• Biology is the scientific study of life

• Biologists are moving closer to understanding:

– How a single cell develops into an organism

– How plants convert sunlight to chemical energy

– How the human mind works

– How living things interact in communities

– How life’s diversity evolved from the first microbes



• Life’s basic characteristic is a high degree of order

• Each level of biological organization has emergent properties

Video: Seahorse CamouflageVideo: Seahorse Camouflage



• Concept 1.1: Biologists explore life from the microscopic to the global scale

• The study of life extends from molecules and cells to the entire living planet

• Biological organization is based on a hierarchy of structural levels


A Hierarchy of Biological Organization

1. Biosphere: all environments on Earth

2. Ecosystem: all living and nonliving things in a particular area

3. Community: all organisms in an ecosystem

4. Population: all individuals of a species in a particular area

5. Organism: an individual living thing


A Hierarchy of Biological Organization (continued)

6. Organ and organ systems: specialized body parts made up of tissues

7. Tissue: a group of similar cells

8. Cell: life’s fundamental unit of structure and function

9. Organelle: a structural component of a cell

10. Molecule: a chemical structure consisting of atoms

Ecosystems

The biosphere

Organisms

Populations

Communities

Cells

Organelles

Molecules

Tissues

Organs and organ systems

Cell1 µm

Atoms

10 µm

50 µm


A Closer Look at Ecosystems

• Each organism interacts with its environment

• Both organism and environment affect each other


Ecosystem Dynamics

• The dynamics of an ecosystem include two major processes:

– Cycling of nutrients, in which materials acquired by plants eventually return to the soil

– The flow of energy from sunlight to producers to consumers


Energy Conversion

• Activities of life require work

• Work depends on sources of energy

• Energy exchange between an organism and environment often involves energy transformations

• In transformations, some energy is lost as heat

• Energy flows through an ecosystem, usually entering as light and exiting as heat

LE 1-4

Sunlight

Ecosystem

Heat

Heat

Chemicalenergy

Consumers(including animals)

Producers(plants and otherphotosynthetic

organisms)


A Closer Look at Cells

• The cell is the lowest level of organization that can perform all activities of life

• The ability of cells to divide is the basis of all reproduction, growth, and repair of multicellular organisms

LE 1-5

25 µm


The Cell’s Heritable Information

• Cells contain DNA, the heritable information that directs the cell’s activities

• DNA is the substance of genes

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

LE 1-6

Sperm cell

NucleicontainingDNA

Egg cell

Fertilized eggwith DNA fromboth parents

Embryo’s cells With copies of inherited DNA

Offspring with traits inherited from both parents


• Each DNA molecule is made up of two long chains arranged in a double helix

• Each link of a chain is one of four kinds of chemical building blocks called nucleotides

LE 1-7

DNA double helix Single strand of DNA

Nucleotide

Cell

Nucleus DNA


Two Main Forms of Cells

• Characteristics shared by all cells:

– Enclosed by a membrane

– Use DNA as genetic information

• Two main forms of cells:

– Eukaryotic: divided into organelles; DNA in nucleus

– Prokaryotic: lack organelles; DNA not separated in a nucleus

LE 1-8

Membrane

Cytoplasm

EUKARYOTIC CELL PROKARYOTIC CELL

DNA(no nucleus)

Membrane

1 µm

Organelles

Nucleus (contains DNA)


• Concept 1.2: Biological systems are much more than the sum of their parts

• A system is a combination of components that form a more complex organization

• Cells, organisms, and ecosystems are some examples of biological systems


The Emergent Properties of Systems

• Emergent properties result from arrangements and interactions within systems

• New properties emerge with each step upward in the hierarchy of biological order


The Power and Limitations of Reductionism

• Reductionism is reducing complex systems to simpler components that are easier to study

• The studies of DNA structure and the Human Genome Project are examples of reductionism



Systems Biology

• Systems biology seeks to create models of the dynamic behavior of whole biological systems

• An example is a systems map of interactions between proteins in a fruit fly cell

• Such models may predict how a change in one part of a system will affect the rest of the system

LE 1-10

CELL

Nucleus

Cytoplasm

Outer membraneand cell surface


• Systems biology uses three key research developments:

– High-throughput technology: methods to generate large data sets rapidly

– Bioinformatics: using computers and software to process and integrate large data sets

– Interdisciplinary research teams


Feedback Regulation in Biological Systems

• Regulatory systems ensure a dynamic balance in living systems

• Chemical processes are catalyzed (accelerated) by enzymes

• Many biological processes are self-regulating: the product regulates the process itself


• In negative feedback, the accumulation of a product slows down the process itself

• In positive feedback (less common), the product speeds up its own production

Animation: Negative FeedbackAnimation: Negative Feedback Animation: Positive FeedbackAnimation: Positive Feedback

LE 1-11

Enzyme 1

A A

BB

C C

DD

D

DD

D

D

D

DDD

Enzyme 2

Enzyme 3

Negativefeedback

Enzyme 1

LE 1-12

W

Enzyme 4

W

XX

Y Y

ZZ

ZZ

Z ZZ

ZZ Z

Enzyme 5

Enzyme 6

Positivefeedback

Enzyme 4

Enzyme 6

Enzyme 5

Z

Z Z Z

Z

Z

Z

ZZ


• Concept 1.3: Biologists explore life across its great diversity of species

• Biologists have named about 1.8 million species

• Estimates of total species range from 10 million to over 200 million



Grouping Species: The Basic Idea

• Taxonomy is the branch of biology that names and classifies species into a hierarchical order

• Kingdoms and domains are the broadest units of classification

LE 1-14

Ursidae

Ursus

Carnivora

Mammalia

Chordata

Animalia

Eukarya

Species Genus Family Order Class Phylum Kingdom DomainUrsusamericanus(Americanblack bear)


The Three Domains of Life

• At the highest level, life is classified into three domains:

– Bacteria (prokaryotes)

– Archaea (prokaryotes)

– Eukarya (eukaryotes)Eukaryotes include protists and the kingdoms Plantae, Fungi, and Animalia

LE 1-15

Bacteria 4 µm 100 µm

0.5 µm

Kingdom PlantaeProtists

Kingdom AnimaliaKingdom FungiArchaea


Unity in the Diversity of Life

• Underlying life’s diversity is a striking unity, especially at lower levels of organization

• In eukaryotes, unity is evident in details of cell structure

LE 1-16a

Cilia of windpipe cellsCilia of Paramecium

15 µm 5 µm

LE 1-16b

Cilia of windpipe cellsCilia of Paramecium

Cross section of cilium,as viewed with anelectron microscope

0.1 µm


• Concept 1.4: Evolution accounts for life’s unity and diversity

• The history of life is a saga of a changing Earth billions of years old



• The evolutionary view of life came into sharp focus in 1859, when Charles Darwin published On the Origin of Species by Natural Selection

• “Darwinism” became almost synonymous with the concept of evolution



• The Origin of Species articulated two main points:

– Descent with modification (the view that contemporary species arose from a succession of ancestors)

– Natural selection (a proposed mechanism for descent with modification)

• Some examples of descent with modification are unity and diversity in the orchid family



Natural Selection

• Darwin inferred natural selection by connecting two observations:

– Observation: Individual variation in heritable traits

– Observation: Overpopulation and competition

– Inference: Unequal reproductive success

– Inference: Evolutionary adaptation

LE 1-20

Evolution of adaptationsin the population

Differences inreproductive success

Overproductionand competition

Populationof organisms

Hereditaryvariations


• Natural selection can “edit” a population’s heritable variations

• An example is the effect of birds preying on a beetle population

LE 1-21

Population with varied inherited traits

Elimination of individuals with certain traits

Reproduction of survivors

Increasing frequency of traits that enhancesurvival and reproductive success


• Natural selection is often evident in adaptations of organisms to their way of life and environment

• Bat wings are an example of adaptation

Video: Soaring HawkVideo: Soaring Hawk



The Tree of Life

• Many related organisms have similar features adapted for specific ways of life

• Such kinships connect life’s unity and diversity to descent with modification

• Natural selection eventually produces new species from ancestral species

• Biologists often show evolutionary relationships in a treelike diagram

[Videos on slide following the figure]

LE 1-23Largeground finch

Large cactusground finch

Sharp-beakedground finch

Geospizamagnirostris

Geospizaconirostris

Mediumground finch

Geospizafuliginosa

Smallground finch

Woodpecker finch

Camarhynchuspsittacula

Large tree finch

Medium tree finch

Cactusground finch

Geospizadifficilis

Cactus flowereaters

Geospizascandens

Seed eater

Ground finches

Seed eaters

Tree finches

Common ancestor fromSouth American mainland

Insect eaters Bud eater

Warbler finches

Mangrove finchGeospiza

fortis

Cactospizapallida Small

tree finch

Camarhynchuspauper

Camarhynchusparvulus

Greenwarblerfinch

Graywarblerfinch

Certhideaolivacea

Certhideafusca

Vegetarianfinch

Platyspizacrassirostris

Cactospizaheliobates


Video: Albatross Courtship RitualVideo: Albatross Courtship Ritual

Video: Blue-footed Boobies Courtship RitualVideo: Blue-footed Boobies Courtship Ritual

Video: GalapVideo: Galapáágos Islands Overviewgos Islands Overview

Video Galapágos Marine IguanaVideo Galapágos Marine Iguana

Video: Galapágos Sea LionVideo: Galapágos Sea Lion

Video: Galapágos TortoiseVideo: Galapágos Tortoise


• Concept 1.5: Biologists use various forms of inquiry to explore life

• Inquiry is a search for information and explanation, often focusing on specific questions

• The process of science blends two main processes of scientific inquiry:

– Discovery science: describing nature

– Hypothesis-based science: explaining nature


Discovery Science

• Discovery science describes nature through careful observation and data analysis

• Examples of discovery science:

– understanding cell structure

– expanding databases of genomes


Types of Data

• Data are recorded observations

• Two types of data:

– Quantitative data: numerical measurements

– Qualitative data: recorded descriptions



Induction in Discovery Science

• Inductive reasoning involves generalizing based on many specific observations


Hypothesis-Based Science

• In science, inquiry usually involves proposing and testing hypotheses

• Hypotheses are hypothetical explanations


The Role of Hypotheses in Inquiry

• In science, a hypothesis is a tentative answer to a well-framed question

• A hypothesis is an explanation on trial, making a prediction that can be tested

LE 1-25a

Hypothesis #1:Dead batteries

Hypothesis #2:Burnt-out bulb

Observations

Question

LE 1-25b

Hypothesis #1:Dead batteries

Hypothesis #2:Burnt-out bulb

Test prediction

Test falsifies hypothesis

Prediction:Replacing batterieswill fix problem

Prediction:Replacing bulbwill fix problem

Test prediction

Test does not falsify hypothesis


Deduction: The “If…then” Logic of Hypothesis-Based Science

• In deductive reasoning, the logic flows from the general to the specific

• If a hypothesis is correct, then we can expect a particular outcome


A Closer Look at Hypotheses in Scientific Inquiry

• A scientific hypothesis must have two important qualities:

– It must be testable

– It must be falsifiable


The Myth of the Scientific Method

• The scientific method is an idealized process of inquiry

• Very few scientific inquiries adhere rigidly to the “textbook” scientific method


• In mimicry, a harmless species resembles a harmful species

• An example of mimicry is a stinging honeybee and a nonstinging mimic, a flower fly

A Case Study in Scientific Inquiry: Investigating Mimicry in Snake Populations

LE 1-26

Flower fly (nonstinging)

Honeybee (stinging)


• This case study examines king snakes’ mimicry of poisonous coral snakes

• The hypothesis states that mimics benefit when predators mistake them for harmful species

• The mimicry hypothesis predicts that predators in non–coral snake areas will attack king snakes more frequently than will predators that live where coral snakes are present

LE 1-27

Scarlet king snake

Eastern coralsnake

Scarlet king snake

Key

Range of scarlet king snake

NorthCarolina

Range of easterncoral snake

SouthCarolina


Field Experiments with Artificial Snakes

• To test this mimicry hypothesis, researchers made hundreds of artificial snakes:

– An experimental group resembling king snakes

– A control group resembling plain brown snakes

• Equal numbers of both types were placed at field sites, including areas without coral snakes

• After four weeks, the scientists retrieved the artificial snakes and counted bite or claw marks

• The data fit the predictions of the mimicry hypothesis

LE 1-28

(a) Artificial king snake

(b) Artificial brown snake that has been attacked

In areas where coral snakes were present, most attacks were on brown artificial snakes.

In areas where coral snakeswere absent, most attacks

were on artificial king snakes.

LE 1-29

% of attacks onartificial king snakes

% of attacks onbrown artificial snakes

Field site withartificial snakes

83%

NorthCarolina

SouthCarolina

17%

16%

84%

Key


Designing Controlled Experiments

• Scientists do not control the experimental environment by keeping all variables constant

• Researchers usually “control” unwanted variables by using control groups to cancel their effects


Limitations of Science

• The limitations of science are set by its naturalism

– Science seeks natural causes for natural phenomena

– Science cannot support or falsify supernatural explanations, which are outside the bounds of science


Theories in Science

• A scientific theory is much broader than a hypothesis

• A scientific theory is:

– broad in scope

– general enough to generate new hypotheses

– supported by a large body of evidence


Model Building in Science

• Models are representations of ideas, structures, or processes

• Models may range from lifelike representations to symbolic schematics

LE 1-30Frombody

Fromlungs

Rightatrium

Leftatrium

Rightventricle

Leftventricle

To lungs To body


The Culture of Science

• Science is an intensely social activity

• Both cooperation and competition characterize scientific culture



Science, Technology, and Society

• The goal of science is to understand natural phenomena

• Technology applies scientific knowledge for some specific purpose



• Concept 1.6: A set of themes connects the concepts of biology

• Biology is the science most connected to the humanities and social sciences

• Underlying themes provide a framework for understanding biology










01 lectures ppt

Science

pearson education

benjamin cummingscopyright

benjamin cummings overview

benjamin cummings concept

benjamin cummingsa closer

chemical energy

energy transformations

flow of energy