Ap bio lecture ch1 a view of life

A View of LifeA View of LifeWarmUp Questions

1.What are the eleven levels of biological organization in order from largest to smallest?

2.Name 4 characteristics of life.

3.Can you differentiate between inductive and deductive reasoning?

A View of LifeA View of Life

The phenomenon we call…

LIFE

A View of LifeChapter 01


Biologists use various forms of inquiry to explore life

At the heart of science is inquiry◦ A search for information and explanation, often

focusing on specific questions Biology blends two main processes of

scientific inquiry◦ Discovery science◦ Hypothesis-based science


◦ Describes natural structures and processes as accurately as possible through careful observation and analysis of data


Data◦ Are recorded observations◦ Can be quantitative or qualitative

Figure 1.24


In inductive reasoning◦ Scientists derive generalizations based on a large

number of specific observations


In science, inquiry that asks specific questions◦ Usually involves the proposing and testing of

hypothetical explanations, or hypotheses


In science, a hypothesis◦ Is a tentative answer to a well-framed question, an

explanation on trial◦ Makes predictions that can be tested


Observations

Questions

Hypothesis # 1:Dead batteries

Hypothesis # 2:Burnt-out bulb

Prediction:Replacing batterieswill fix problem

Prediction:Replacing bulbwill fix problem

Test prediction

Test does not falsify hypothesis

Test prediction

Test falsifies hypothesisFigure 1.25

We use simple hypotheses ALL THE TIME


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 scientific hypothesis must have two important qualities◦ It must be testable◦ It must be falsifiable


The scientific method◦ Is an idealized process of inquiry

Very few scientific inquiries◦ Adhere to the “textbook” scientific method


In mimicry◦ A harmless species resembles a harmful species

Flower fly(non-stinging)

Honeybee (stinging)Figure 1.26


In this case study◦ Mimicry in king snakes is examined◦ The 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

Scarlet king snake

Scarlet king snakeKey

Range of scarlet king snake

Range of eastern color snake

Eastern coral snake

NorthCarolina

SouthCarolina

Figure 1.27


To test this mimicry hypothesis◦ Researchers made

hundreds of artificial snakes, an experimental group resembling king snakes and a control group of plain brown snakes

(a) Artificial king snake

(b) Brown artificial snake that has been attackedFigure 1.28


After a given period of time◦ The researchers

collected data that fit a key prediction

Figure 1.29

In areas where coral snakes were present, most attacks were on brownartificial snakes

Key

% of attacks on artificial king snakes

% of attacks on brown artificial snakes

Field site with artificial snakes

17%

83%

NorthCarolina

SouthCarolina

XXXX X

XX

XXX

XXXX

In areas where coral snakeswere absent, most attacks

were on artificial king snakes

84%

16%

Key


Experiments must be designed to test◦ The effect of one variable by testing control groups

and experimental groups in a way that cancels the effects of unwanted variables


Science cannot address supernatural phenomena◦ Because hypotheses must be testable and

falsifiable and experimental results must be repeatable


A scientific theory◦ Is broad in scope◦ Generates new hypotheses◦ Is supported by a large body of evidence


Defining Life◦ Emergent Properties

◦ Organized

◦ Materials and Energy

◦ Response

◦ Reproduce and Develop

◦ Adaptations and Natural Selection

Biosphere Organization

◦ Human Population

◦ Biodiversity

Classification

The Scientific Method

21


Living things vs. nonliving objects:

◦ Comprised of the same chemical elements

◦ Obey the same physical and chemical laws

The cell is the smallest, most basic unit of all life

◦ Familiar organisms are multicellular

◦ Some cells independent – single-celled organisms

22

23Defining Life


Emergent Properties – Biological organization

◦ Levels range from extreme micro to global

◦ Each level up:

More complex than the preceding level

Properties:

A superset of preceding level’s properties emerge from interactions between components

24

25Levels of Biological Organization

26

Living Things:

1.1. Demonstrate OrderDemonstrate Order

2.2. Self-regulationSelf-regulation

3.3. Growth and DevelopmentGrowth and Development


Energy - the capacity to do work

◦ The sun:

Ultimate source of energy for nearly all life on Earth

Drives photosynthesis

◦ Metabolism - all the chemical reactions in a cell

Homeostasis - Maintenance of internal conditions within certain boundaries

27

28Acquiring Nutrients


Living things detect changes in environment

Response often involves movement

◦ Vulture can detect and find carrion a mile away

◦ Monarch butterfly senses fall and migrates south

◦ Microroganisms follow light or chemicals

◦ Even leaves of plants follow sun

Responses collectively constitute behavior

29


Organisms live and die

Must reproduce to maintain population

Multicellular organisms:

◦ Begins with union of sperm and egg

◦ Developmental instructions encoded in genes

Composed of DNA

Long spiral molecule in chromosomes

30

31Rockhopper Penguins & Offspring


Adaptation

◦ Any modification that makes an organism more suited to its way of life

◦ Organisms, become modified over time

◦ However, organisms very similar at basic level

Suggests living things descended from same ancestor

Descent with modification - Evolution

Caused by natural selection

32


Population - Members of a species within an area

Community - A local collection of interacting populations

Ecosystem - The communities in an area considered with their physical environment

How chemicals are cycled and re-used by organisms

How energy flows, from photosynthetic plants to top predators

33

34Terrestrial Ecosystems:A Grassland

35Marine Ecosystems:A Coral Reef


Ecosystems negatively impacted by human populations

◦ Destroyed for agriculture, housing, industry, etc.

◦ Degraded and destabilized by pollution

However, humans depend upon healthy ecosystems for

◦ Food

◦ Medicines

◦ Raw materials

◦ Other ecosystem processes

36


Biodiversity:

◦ The total number of species (est. 15 million)

◦ The variability of their genes

◦ The ecosystems in which they live

Extinction:

◦ The death of the last member of a species

◦ Estimates of 400 species/day lost worldwide

37


Taxonomy:◦ The rules for identifying and classifying organisms

◦ Hierarchical levels (taxa) based on hypothesized evolutionary relationships

◦ Levels are, from least inclusive to most inclusive: Species, genus, family, order, class, phylum,

kingdom, and domain

A level usually includes more species than the level below it, and fewer species than the one above it

38

A View of LifeA View of Life 39

Z. maysZ. maysH. sapiensH. sapiensSpeciesSpecies

ZeaZeaHomoHomoGenusGenus

PoacaePoacaeHominidaeHominidaeFamilyFamily

CommelinalesCommelinalesPrimatesPrimatesOrderOrder

LiliopsidaLiliopsidaMammaliaMammaliaClassClass

AnthophytaAnthophytaChordataChordataPhylumPhylum

PlantaePlantaeAnimaliaAnimaliaKingdomKingdom

EukaryaEukaryaEukaryaEukaryaDomainDomain

CornCornHumanHumanTaxonTaxon


Bacteria

◦ Microscopic unicellular prokaryotes

Archaea

◦ Bacteria-like unicellular prokaryotes

◦ Extreme aquatic environments

Eukarya

◦ Eukaryotes – Familiar organisms

40

41Domains:The Archaea

42Domains:The Bacteria


Archaea – Kingdoms still being worked out

Bacteria - Kingdoms still being worked out

Eukarya

◦ Kingdom Protista

◦ Kingdom Fungi

◦ Kingdom Plantae

◦ Kingdom Animalia

43

44Domains:The Eukaryote Kindoms


Binomial nomenclature (two-word namess)

Universal

Latin-based◦ First word represents genus of organism

◦ Second word is specific epithet of a species within the genus

◦ Always Italicized asa Genus species (Homo sapiens)

◦ Genus may occur alone (Homo), but not specific epithet

45


Begins with observation

◦ Scientists use their five senses

◦ Instruments can extend the range of senses

Hypothesis

◦ A tentative explanation for what was observed

◦ Developed through inductively reasoning from specific to general

46

47The Scientific Method:

A Flow Diagram


Experimentation◦ Purpose is to challenge the hypothesis

◦ Designed through deductively reasoning from general to specific

◦ Often divides subjects into a control group and an experimental group

◦ Predicts how groups should differ if hypothesis is valid If prediction happens, hypothesis is unchallenged

If not, hypothesis is unsupportable

48


Results

◦ Observable, objective results from an experiment

◦ Strength of the data expressed in probabilities

◦ The probability that random variation could have caused the results

Low probability (less than 5%) is good

Higher probabilities make it difficult to dismiss random chance as the sole cause of the results

49


The results are analyzed and interpreted

Conclusions are what the scientist thinks caused the results

Findings must be reported in scientific journals

Peers review the findings and the conclusions

Other scientists then attempt to duplicate or dismiss the published findings

50


Scientific Theory:

◦ Joins together two or more related hypotheses

◦ Supported by broad range of observations, experiments, and data

Scientific Principle / Law:

◦ Widely accepted set of theories

◦ No serious challenges to validity

51


Experimental (Independent) variable

◦ Applied one way to experimental group

◦ Applied a different way to control group

Response (dependent) variable

◦ Variable that is measured to generate data

◦ Expected to yield different results in control versus experimental groups

52


Observations:

◦ Nitrate fertilizers boost grain crops, but may damage soils

◦ When grain crops are rotated with pigeon pea it adds natural nitrogen

Hypothesis:

◦ Pigeon pea rotation will boost crop production as much as nitrates

◦ Pigeon pea rotation will NOT damage soils

53

54Root Nodules


Experimental Design◦ Control Group

Winter wheat planted in pots without fertilizer

◦ Experimental Groups 1-Winter wheat planted in pots with 45 kg/ha nitrate

2-Winter wheat planted in pots with 90 kg/ha nitrate

3-Winter wheat planted in pots that had grown a crop of pigeon peas

◦ All groups treated identically except for above

55

56Crop Rotation Study


Experimental Prediction:◦ Wheat production following pigeon pea rotation

will be equal or better than following nitrate fertilizer

Results◦ 45 kg/ha produced slightly better than controls

◦ 90 kg/ha produced nearly twice as much as controls

◦ Pigeon pea rotation did not produce as much as the controls

57


Conclusion

◦ Research hypothesis was not supported by results

◦ However, research hypothesis was not proven false by negative results

Revised experiment

◦ Grow wheat in same pots for several generations

◦ Look for soil damage in nitrate pots and improved production in pigeon pea pots

58


Results◦ After second year:

Production following nitrates declined Production following pigeon pea rotation was

greatest of all

◦ After third year Pigeon pea rotation produced 4X as much as controls

Revised conclusions◦ Research hypothesis supported◦ Pigeon pea rotation should be recommended over

nitrates

59

60A Field Study


Defining Life - Emergent Properties

◦ Materials and Energy

◦ Reproduction and Development

◦ Adaptations and Natural Selection

Biosphere Organization

◦ Human Population

◦ Biodiversity

Classification

The Scientific Method

61

A View of LifeEnding Slide Chapter 01

Ap bio lecture ch1 a view of life

Education

view of life science

view of life data

view of life energy

view of life biologists

view of life experiments

characteristics of life

view of life living

view of life warmup