Biology Presentation Chapter 1

8/6/2019 Biology Presentation Chapter 1

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Invitation to Biology

Chapter 1


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1.1Impacts/Issues:

The Secret Life of Earth

Biology

The systematic study of life

We have encountered only a fraction of the

organisms that live on Earth

Scientists constantly discover new species

Extinction rates are accelerating


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Exploring New Guinea

A rare golden-mantled tree kangaroo


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1.2 Lifes Levels of Organization

The building blocks (atoms) that make up all

living things are the same ones that make up allnonliving things

The unique properties of life emerge as certain

kinds of molecules become organized into cells


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Lifes Levels of Organization

Atom Fundamental building block of all matter

Molecule

An association of two or more atoms

Cell

Smallest unit of life

Organism An individual; consists of one or more cells


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Lifes Levels of Organization

Population Group of individuals of a species in a given area

Community

All populations of all species in a given area

Ecosystem

A community interacting with its environment

Biosphere All regions of Earth that hold life


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Nature and Life

Nature

Everything in the universe, except what humanshave manufactured

Emergent property

A characteristic of a system that does not appear

in any of a systems component parts


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Levels of Organization in Nature


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3

Fig. 1-2, p. 5

2

8

1

7

6

45


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Animation: Lifes levels of organization
http://videos_animations/organization.html


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Active Figure: Levels of organization
http://videos_animations/levels_life.html


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1.3 Overview of Lifes Unity

All living things have similar characteristics Require energy and nutrients

Sense and respond to change

Reproduce with the help of DNA


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Energy Sustains Lifes Organization

One-way flow of energy through the biosphereand cycling of nutrients among organismssustain lifes organization

Energy The capacity to do work

Nutrient

Substance that is necessary for survival, but thatan organism cant make for itself


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Organisms and Energy Sources

Producers

Organisms that make their own food using energy

and simple raw materials from the environment

Example: plants

Consumers

Organisms that get energy and carbon by feeding

on tissues, wastes, or remains of other organisms

Example: animals


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Energy Flow and Material Cycling


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19/62Fig. 1-3a, p. 6

sunlight

energy A Producers harvest energy

from the environment. Some

of that energy flows from

producers to consumers.

PRODUCERSplants and other

self-feeding organisms

CONSUMERSanimals, most fungi,

many protists, bacteria

C All energy that enters the world

of life eventually flows out of it,mainly as heat. Stepped Art

B Nutrients thatbecome incorporated

into the cells of producersand consumers are

eventually released bydecomposition. Some

cycle back toproducers.


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Organisms Sense and Respond to Change

Organisms sense and respond to change to keepconditions in their internal environment within a

range that favors cell survival (homeostasis)

Homeostasis

Set of processes by which an organism keeps its

internal conditions within tolerable ranges

Receptor

Molecule or structure that responds to a stimulus


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Response to Stimuli


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Organisms Grow, Develop and Reproduce

Organisms grow, develop, and reproducebasedon information encoded in DNA, which theyinherit from their parents

Growth

Increase in size, volume, and number of cells inmulticelled species

Development

Multistep process by which the first cell of a new

individual becomes a multicelled adult


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Organisms Grow, Develop and Reproduce

Reproduction

Process by which parents produce offspring

Inheritance

Transmission of DNA from parents to offspring

DNA (Deoxyribonucleic acid)

Molecule that carries hereditary information about

traits


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1.4 Introduction to Lifes Diversity

The millions of species on Earth vary greatly indetails of body form and function

Each species is given a unique two-part name

that includes genus and species names

Species

A type of organism

Genus

Group of species that share a unique set of traits


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Classification Systems

Classification systems group species according

to traits and organize information about species

One system sorts all organisms into one of three

domains: Bacteria, Archaea, and Eukarya

The eukaryotes include plants, protists, fungi

and animals

Lif Di it


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Lifes Diversity:

Three-Domain Classification System


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Fig. 1-5, p. 8

Bacteria Archaea

Eukarya


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Animation: Lifes diversity
http://videos_animations/life_diversity_v2.html


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Eukaryotes

Plant

Typically a multicelled, photosynthetic producer

Animal

Multicelled consumer that develops through a

series of embryonic stages and moves about

during all or part of the life cycle


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Animation: Three domains
http://videos_animations/three_domains.html


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1.5 The Nature of Scientific Inquiry

Critical thinking Mental process of judging the quality of information

before deciding whether or not to accept it


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The Scope and Limits of Science

Science is a way of looking at the natural world

which helps us to communicate our experiences

without bias by focusing only on testable ideas

about observable phenomena

Sciencedoes not address the supernatural

Science The systemic study of nature


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1.6 How Science Works

Researchers make and test potentially falsifiablepredictions about how the natural world works

Generally, scientific inquiry involves forming ahypothesis (testable assumption) about anobservation then making and testing predictionsbased on the hypothesis

A hypothesis that is not consistent with the resultsof scientific tests is modified or discarded


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Common Research Practices

1. Observe some aspect of nature

2. Frame a question about your observation

3. Propose a hypothesis (a testable explanationof the observation)


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4. Make a prediction a statement based on a

hypothesis, about some condition that shouldexist if the hypothesis is not wrong

5. Test the accuracy of the prediction by

experiments or gathering information (tests maybe performed on a model)


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6. Assess the results of the tests (data) to see if

they support or disprove the hypothesis

7. Conclusions: Report all steps of your work and

conclusions to the scientific community


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Laws of Nature

Law of nature

Generalization that describes a consistent anduniversal natural phenomenon for which we do

not yet have a complete scientific information

Example: gravity


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Examples of Scientific Theories


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1.7 The Power of Experiments

Natural processes are often influenced by many

interacting variables

Variable

A characteristic or event that differs among

individuals


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The Power of Experiments

Experiments simplify interpretations of complex

biological systems by focusing on the effect ofone variable at a time

Experiment

A test to support or falsify a prediction


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Experimental and Control Groups

Experimental group

A group of objects or individuals that display orare exposed to a variable under investigation

Control group

A group of objects or individuals that is identical

to an experimental group except for one variable


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Potato Chips and Stomachaches


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Fig. 1-7, p. 12

AOlestra causes intestinal cramps.Hypothesis

B PredictionPeople who eat potato chips made withOlestra will be more likely to getintestinal cramps than those who eatpotato chips made without Olestra.

C Experiment Control Group ExperimentalGroup

Eats regularpotato chips

Eats Olestrapotato chips

D 93 of 529 peopleget cramps later(17.6%)

89 of 563 peopleget cramps later(15.8%)

Results

E ConclusionPercentages are about equal. People whoeat potato chips made with Olestra are

just as likely to get intestinal cramps asthose who eat potato chips made withoutOlestra. These results do not support the

hypothesis.

HypothesisOl t i t ti l


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Results 93 of 529 people

get cramps later

(17.6%)

89 of 563 people get

cramps later

(15.8%)

Experiment Control Group

Eats regular

potato chips

Experimental Group

Eats Olestra

potato chips

Olestra causes intestinal cramps.

Prediction

People who eat potato chips made with Olestra will be more

likely to get intestinal cramps than those who eat potatochips made without Olestra

Conclusion

Percentages are about equal. People who eat potato chips

made with Olestra are just as likely to get intestinal cramps

as those who eat potato chips made without Olestra.

These results do not support the hypothesis.

Fig. 1-10, p. 14Stepped Art


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Example: Butterflies and Birds

Question Why does a peacock butterfly flick its wings?

Two hypotheses Exposing wing spots scares off predators

Wing sounds scare off predators

Two predictions

Individuals without spots are eaten more often

Individuals without sounds are eaten more often


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Peacock Butterfly Defenses


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Experiments and Results

Four groups of butterflies were exposed to

predators (birds)

Butterflies without spots

Butterflies without sounds

Butterflies without spots or sounds

Control group

Test results support both original hypotheses


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Results: Peacock Butterfly Experiment


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Sampling Error

Biology researchers experiment on subsets of a

group, which may result in sampling error

Sampling error

Difference between results derived from testing

an entire group of events or individuals, andresults derived from testing a subset of the group


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Sampling Error


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Fig. 1-9, p. 14

24

20

16

12

8

Wing-fl ic

kspe

rminute

4

0 spots

+ sound

spots

sound

+ spots

sound


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Probability

Researchers try to design experiments carefully

in order to minimize sampling error

Statistically significant

Refers to a result that is statistically unlikely to

have occurred by chance


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Animation: Sampling error
http://videos_animations/sample_error.html


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1.8 Impacts/Issues Revisited

Biologists constantly discover new species Mouse lemur (Microcebus lehilahytsara),

discovered in Madagascar in 2005

Digging Into Data:


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gg g

Peacock Butterfly Predator Defenses

Biology Presentation Chapter 1

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