chapter 1 gen bio

1

Introduction: Themes in the Study of Life Chapter 1

1

You will be able to:

1. Briefly describe the unifying themes that

characterize the biological sciences

2. Distinguish among the three domains of

life, and the eukaryotic kingdoms

3. Distinguish between the following pairs of

terms: discovery science and hypothesis-

based science, quantitative and qualitative

data, inductive and deductive reasoning,

science and technology

2

Biology:

The scientific study of life

Biologists answer such questions as:

o How does a single cell develop into an organism?

o How does the human mind work?

o How do living things interact in communities (ex forest)?

3

2

What is Life?

Life defies a simple, one-sentence definition

Life is recognized by what living things do

Properties and processes associated with life:

o Have order

o Evolutionary adaptation

o Respond to environment

o Regulation

o Energy processing

o Growth and development

o Reproduction

4

Fig. 1-3a

Order

Perfectly ordered to work

-Patterned

5

Fig. 1-3b

Evolutionary adaptation

o Appearance of pigmy

sea horse camouflages it

within its environment.

o Such adaptations evolve

over many generations.

6

3

Fig. 1-3c

Response to the environment

7

Venus flytrap closes

its trap rapidly in

response to the

environmental

stimulus of a damselfly

Reproduction

As a group, maybe

not all individuals

8

Fig. 1-3e

Growth and development 9

Inherited information

carried by genes

controls the pattern of

growth and

development

4

Fig. 1-3f

Energy processing

o Change energy to

other forms, to

accomplish a task

o Ex hummingbird

obtains fuel in the form

of nectar from flowers

o The chemical energy

stored in the food will

power flight and other

work

10

Fig. 1-3g

Regulation

o Maintain conditions

suitable for life

(temperature, blood

sugar, etc)

o Ex jackrabbits ears used to maintain

constant body

temperature

o Blood vessels in ears

adjust heat exchange

with surrounding air

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12

Themes Connect the Concepts of Biology

1. New properties emerge at each level in the biological hierarchy

2. Organisms interact with other organisms and the physical

environment

3. Life requires energy transfer and transformation

4. Structure and function are correlated at all levels of biological

organization

5. Cells are an organisms basic units of structure and function 6. The continuity of life is based on heritable information in the

form of DNA

7. Feedback mechanisms regulate biological systems

8. Evolution is the overarching theme of biology

o Biology consists of more than memorizing factual details

o 8 unifying themes help to organize biological information and

make sense of biological information

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13

Theme 1: New properties emerge at each

level in the biological hierarchy o Biological organization is based on hierarchy of structural

levels, each building on the levels below

o At the lowest level are atoms which are organized into

complex molecules

Molecules

Atoms

Chlorophyll molecule

Molecule: Chemical structure that consists of 2 or more small chemical units called atoms

14


level in the biological hierarchy

o Molecules are organized into organelles

Chloroplast

1 m

Organelles

Organelle: Functional components within a cell Example - Chloroplast

Cell

Cells

10 m

15

o Cells, containing organelles, are

the fundamental unit of structure

and function of living things

o Some organisms have one cell

(unicellular), some have many

(multicellular)

o Whether unicellular or

multicellular, all organisms uptake

and process nutrients, excrete

waste, respond to environmental

stimuli, and reproduce.



6

16


level in the biological hierarchy o Multicellular organisms have 3 major structural levels above a

cell: tissues, organs, and organ systems.

Tissues

50 m

Tissue: Group of similar cells Example - Epidermis

17


level in the biological hierarchy o Multicellular organisms have 3 major structural levels above a

cell: tissues, organs, and organ systems.

Organs and organ systems

Organ: Body part with multiple tissue types to do a job. Leaf

Organ System: Multiple organs that work together to do a job

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Organisms

The tree with the tree house



7

19

Populations

Organisms make up populations: localized groups of organisms belonging to the same species Example - Sugar Maple Trees (Acer saccharum) and white-tailed deer



20

Communities

Populations of several species in the same area combine to form a biological community. The living things in an ecosystem Example - trees, bears, birds, mushrooms, etc



21

Ecosystems

Populations interact with their physical environment

to form ecosystems. Particular area and everything interacting within it Example - Forrest (water, trees, bears, air, etc),

grasslands, desert, and coral reef



8

The biosphere

Biosphere: Area of earth inhabited by living things most regions of the land, most bodies of water, and the atmosphere



23

Ways to Arrange/Organize Biology

The biosphere

Ecosystems Tissues

Organs and organ systems

Communities

Populations

Organisms

Organelles Cells

Atoms

Molecules

24

Largest

Smallest

1. Biosphere

2. Ecosystems

3. Communities

4. Populations

5. Organisms

6. Organs and Organ Systems

7. Tissues

8. Cells

9. Organelles

10.Molecules

Levels of Biological Organization

Make sure to know order

and examples of each

organization level

9

Emergent Properties

o Emergent properties result from the arrangement and

interaction of parts within a system

o Characteristics of something that only appear when the

component parts are put together a certain way &

interact

o Separate from the individual parts

o Emergent properties characterize nonbiological entities

as well

o For example, a functioning bicycle emerges only

when all of the necessary parts connect in the correct

way

25



Emergent Properties o Chain+Tires+Seat+Frame+Bolts + Put Together =

Bicycle

o No individual part can transport itself or a person

o Skin+Hair+Muscle+Bone+Blood+Nerves+Brain+Etc. + Put Together = Your Body

o No single cell can take a college class

26

o Reductionism is the reduction of complex

systems to simpler components that are more

manageable to study

o For example, studying the molecular structure

of DNA helps us to understand the chemical

basis of inheritance

o An understanding of biology balances

reductionism with the study of emergent

properties

o For example, new understanding comes from

studying the interactions of DNA with other

molecules

27

The Power and Limitations of

Reductionism

10

Systems Biology

o A system is a combination of components that

function together (and have emergent properties)

o Systems biology constructs models for the

dynamic behavior of whole biological systems

o Able to predict how a change in one or more

variables will affect other components and the

whole system

o The systems approach poses questions such as

o How does a drug for blood pressure affect

other organs?

o How does increasing CO2 alter the biosphere?

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29

Theme 2: Organisms Interact with Other

Organisms and the Physical Environment

o Every organism interacts with its environment, including

nonliving factors and other organisms

o Both organisms and their environments are affected by

the interactions between them

oFor example, a tree takes up water and minerals from

the soil and carbon dioxide from the air; the tree

releases oxygen to the air and roots help form soil

30

Animals eat

leaves and fruit

from the tree.

Leaves take in carbon dioxide from the air and release oxygen.

Sunlight

CO2

O2

Cycling

of

chemical

nutrients

Leaves fall to the ground and are decomposed by organisms that return minerals to the soil.

Water and minerals in the soil are taken up by the tree through its roots.

Leaves absorb light energy from the sun.

Figure 1.5

11

31

Theme 3: Life Requires Energy

Transfer and Transformation

o A fundamental characteristic of living organisms is

their use of energy to carry out lifes activities

o Work, including moving, growing, and reproducing,

requires a source of energy

o Living organisms transform energy from one form

to another

o For example, light energy is converted to chemical

energy, then kinetic energy

o Energy flows through an ecosystem, usually

entering as light and exiting as heat

The dynamics of an ecosystem include two major processes: 1. Cycling of nutrients, in which materials acquired by plants eventually

return to the soil

2. The flow of energy from sunlight to producers to consumers

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

heat

32

Heat

Producers absorb light energy and transform it into chemical energy.

Chemical energy

Chemical energy in food is transferred from plants to consumers.

(b) Using energy to do work (a) Energy flow from sunlight to producers to consumers

Sunlight

An animals muscle cells convert chemical energy from food to kinetic energy, the energy of motion.

When energy is used to do work, some energy is converted to thermal energy, which is lost as heat.

A plants cells use chemical energy to do work such as growing new leaves.

Theme 4: Structure and Function are

correlated at all levels of biological

organization

Structure & function of living organisms are

closely related

Example, a leaf is thin and flat, maximizing the capture of light

33

12

(a) Wings a birds wings are aerodynamically efficient shaped

(c) Neurons especially well structured for communication within

the body

(b) Bones wing bones have honeycombed internal structure that

is strong but lightweight

Infoldings of membrane

Mitochondrion

(d) Mitochondria inner membrane carry out many steps in energy production. Infoldings pack a large amount of this membrane into a small space

0.5 m 100 m

34

o The cell is the lowest level of organization that can perform all activities required for life

o You are made of trillions of cells (You are an emergent property!)

o All cells:

o Are enclosed by a membrane

o Use DNA as their genetic information

Theme 5: Cells are an organisms basic units of structure and function

35

Eukaryote vs. Prokaryote o There are 2 basic types of cells: eukaryote

and prokaryote

o A eukaryotic cell has membrane-enclosed

organelles, the largest of which is usually the

nucleus

o By comparison, a prokaryotic cell is simpler

and usually smaller, and does not contain a

nucleus or other membrane-enclosed

organelles

oContains DNA (not in nucleus), plasma

membrane, cytoplasma, and ribosomes only

36

13

Eukaryotic cell

Prokaryotic cell

Cytoplasm

DNA (no nucleus)

Membrane

Nucleus

(membrane-

enclosed)

Membrane

Membrane-

enclosed organelles

DNA (throughout

nucleus) 1 m

Figure 1.8

o Chromosomes contain most of a cells genetic material in the form of DNA (deoxyribonucleic acid)

o DNA is inherited by offspring from their parents

o DNA controls the development and maintenance of

organisms

o The instructions to make physical characteristics

o Genes are the units of inheritance that transmit

information from parents to offspring

o Portions of total DNA

o The instructions to make one heritable characteristic

o The conceptual sentences on the physical page of DNA

Theme 6: The Continuity of Life is Based on

Heritable Information in the Form of DNA

o Each chromosome has

one long DNA molecule

with hundreds or

thousands of genes

o Each DNA molecule is

made up of two long

chains arranged in a

double helix

o Each link of a chain is

one of four kinds of

chemical building blocks

called nucleotides and

nicknamed A, G, C, and

T

39

DNA Structure and Function

Nucleotide

(b) Single strand of DNA

A

C

T

T

A

A

T

C

C

G

T

A

G

T

(a) DNA double helix

A

14

o Living things are made of & by chemicals called

proteins

o Genes are the instructions to make a protein

o Genes control protein production indirectly

o DNA is transcribed into RNA then translated into a

protein (THE CENTRAL DOGMA)

o Gene expression is the process of converting

information from gene to cellular product

o An organisms genome is its entire set of genetic instructions

40

Theme 7: Feedback Mechanisms

Regulate Biological Systems o Feedback mechanisms allow biological processes to

self-regulate

o Negative feedback means that as more of a product

accumulates, the process that creates it slows and

less of the product is produced in life, most common

o Positive feedback means that as more of a product

accumulates, the process that creates it speeds up

and more of the product is produced

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42

Fig. 1-13

Negative feedback

Excess D blocks a step

D

D D

A

B

C

Enzyme 1

Enzyme 2

Enzyme 3

D

(a) Negative feedback

Accumulation of product D

inhibits the 1st enzyme

in the sequence, thus

slowing down production of

more D

W

Enzyme 4

X Positive feedback

Enzyme 5

Y

+

Enzyme 6

Excess Z stimulates a

step

Z

Z

Z

Z

(b) Positive feedback

A product stimulates an enzyme,

Increasing the rate of production

of the product

15

o Nothing in biology makes sense except in the light of evolutionTheodosius Dobzhansky

o Evolution makes sense of everything we know about

biology

o Evolution is defined as decent with modification

o The idea that living species are descendants of

ancestral species that were different from the present-

day ones

o Evolution unifies biology at different scales of size

throughout the history of life on Earth

43

The Core Theme 8: Evolution

accounts for the unity and diversity of

life

44

Organizing the Diversity of Life

o Approximately 1.8 million species have been identified and

named to date, and thousands more are identified each

year

o 100,000 fungi

o 290,000 plants

o 52,000 vertebrates

o 1,000,000 insects

o Estimates of the total number of species that actually exist

range from 10 million to over 100 million

o How do we organize the vast amount of species?

o Taxonomy is the branch of biology that

names and classifies species into groups of

increasing breadth

o Organisms are classed based on similar

characteristics

o Domains, followed by kingdoms, are the

broadest units of classification

45

Grouping Species: The Basic Idea

16

Fig. 1-14

Species Genus Family Order Class Phylum Kingdom Domain

Ursus americanus

(American black bear)

Ursus

Ursidae

Carnivora

Mammalia

Chordata

Animalia

Eukarya

Dashing King Philip Came

Over For Good Soup.

46

Broad

Specific

1. Domain

2. Kingdon

3. Phylum

4. Class

5. Order

6. Family

7. Genus

8. Species

o Organisms are divided into three domains

o Domain Bacteria and domain Archaea comprise the prokaryotes

o Domain Eukarya includes all eukaryotic organisms

The Three Domains of Life

47

48

Figure 1.15

(a) Domain Bacteria (b) Domain Archaea

(c) Domain Eukarya

2

m

2

m

100 m

Kingdom Plantae

Kingdom Fungi

Protists

Kingdom Animalia

17

49

(a) Domain Bacteria

2

m

oComprised of bacteria

oMost diverse and widespread

oPROKARYOTES

50

(b) Domain Archaea

2

m

oMany live in extreme environments

including salty lakes and boiling hot

springs

oPROKARYOTES

51

oDomain Eukarya includes all eukaryotic

organisms

oDomain Eukarya includes three multicellular

kingdoms o Plants, which produce their own food by

photosynthesis

o Fungi, which absorb nutrients from their

surroundings and often decompose dead

organisms and organic wastes o Animals, which ingest their food

Domain Eukarya

18

(c) Domain Eukarya

100 m

Kingdom Plantae

Kingdom Fungi

Protists

Kingdom Animalia

multicellular

multicellular

multicellular

unicellular

In the past: Single-celled eukaryotic organisms were formerly

grouped into a kingdom called Protista, though these are now

often grouped into many separate kingdoms

Organism Groups: Energy Use

o Producers-Receive energy from non-living thing (ex. sunlight) and convert it into form living things can use (chemical energy) (ex. Sugar)

oPlants, some Bacteria

o Consumers-Can only use (eat) chemical bonds (i.e., need food) from living things

oDependent upon Producers

oAnimals, Fungi, You 53

54

Unity in the Diversity of Life

Life is diverse (Domains, Kingdoms, etc), but living things show many similar characteristics

o A striking unity underlies the diversity of life:

o All Organisms are made of One OR Many Cells

o Many features of cell structure are the same or similar

o DNA is the universal genetic language common to all organisms (the instructions to build a living thing)

o Behavior is also similar within Taxonomic Groups

19

55

Figure 1.16

Cilia of Paramecium

15 m

Cross section of a cilium, as viewed with an electron microscope

0.1 m

Cilia of windpipe cells

5 m

Theory of Natural Selection Theory Behind Similarities

Charles Darwin published On the

Origin of Species by Means of

Natural Selection in 1859

2 main points:

1. Species showed evidence of

descent with modification from common ancestors

2. Natural selection is the mechanism

behind descent with modification 56

Darwin observed that:

o Individuals in a population have traits that vary

oMany of these traits are heritable (passed from

parents to offspring)

oMore offspring are produced than survive

oCompetition is inevitable

oSpecies generally suit their environment

o57

20

Darwin inferred that:

o Individuals that are best suited to their

environment are more likely to survive and

reproduce

oOver time, more individuals in a population will

have the advantageous traits

oEventually, the population is different than it was

o The natural environment selects for beneficial traits

o Darwin called this process natural selection

58

Fig. 1-20

Population with varied inherited traits.

Elimination of individuals with certain traits.

Reproduction of survivors.

Increasing frequency of traits that enhance survival and reproductive success.

4 3 2 1

Beetle population:

Mixed Colors

After Forest Fire (ground covered with black ash)

Birds see &

eat lighter beetles

Darker beetles

survive & reproduce

Future

beetles

darker than

ancestors

59

60

The Tree of Life

o Unity in diversity arises from descent with modification

o For example, the forelimb of the bat, human, and

horse and the whale flipper all share a common

skeletal architecture

o Fossils provide additional evidence of anatomical

unity from descent with modification

21

61

o Darwin proposed that natural selection could

cause an ancestral species to give rise to two or

more descendent species

o For example, the finch species of the Galpagos

Islands are descended from a common ancestor

o 14 species of finches diversified adapting to

exploit different food sources on different islands

o Evolutionary relationships are often illustrated with

treelike diagrams that show ancestors and their

descendants

COMMON

ANCESTOR

Green warbler finch

Certhidea olivacea

Gray warbler finch

Certhidea fusca

Sharp-beaked

ground finch

Geospiza difficilis

Vegetarian finch

Platyspiza crassirostris

Mangrove finch

Cactospiza heliobates

Woodpecker finch

Cactospiza pallida

Medium tree finch

Camarhynchus pauper

Large tree finch

Camarhynchus psittacula

Small tree finch

Camarhynchus parvulus

Large cactus

ground finch

Geospiza conirostris

Cactus ground finch

Geospiza scandens

Small ground finch

Geospiza fuliginosa

Medium ground finch

Geospiza fortis

Large ground finch

Geospiza

magnirostris

Inse

ct-e

ate

rs

Seed

-ea

ter B

ud

-ea

ter

Inse

ct-e

ate

rs

Tre

e fin

ch

es

Gro

un

d fin

ch

es

Seed

-ea

ters

Ca

ctu

s-flow

er-

ea

ters

Wa

rble

r finch

es

Figure 1.22

Concept 1.3: In studying nature,

scientists make observations and

then form and test hypotheses

o The word science is derived from Latin and

means to know

o Inquiry is the search for information and

explanation

o There are two main types of scientific inquiry:

discovery science and hypothesis-based science

22

64

Discovery Science (Inductive

Reasoning)

o Discovery science describes natural structures

and processes

o This approach is based on observation and the

analysis of data

o Data are recorded observations or items of

information

65

Types of Data

o Data falls into 2 categories:

oQualitative data, or descriptions rather than

measurements

oFor example, There are many people in the

room

oQuantitative data, or recorded

measurements, which are sometimes

organized into tables and graphs

oFor example, There are 24 people in the

room

Inductive Reasoning

Scientists use inductive reasoning to derive

generalizations based on a large number of

specific observations

For example, The sun always rises in the east

o Observations and inductive reasoning can

lead us to ask questions and propose

hypothetical explanations called

hypotheses

66

23

The Role of Hypotheses in Inquiry

o A hypothesis is a tentative answer to a well-

framed question

o A scientific hypothesis leads to predictions that

can be tested by observation or experimentation

o For example, o Observation: Your flashlight doesnt work o Question: Why doesnt your flashlight work? o Hypothesis 1: The batteries are dead

o Hypothesis 2: The bulb is burnt out

o Both these hypotheses are testable

Observations

Question

Hypothesis #1:

Dead batteries

Hypothesis #2:

Burnt-out bulb

Prediction:

Replacing batteries

will fix problem

Prediction:

Replacing bulb

will fix problem

Test prediction Test prediction

Test falsifies hypothesis Test does not falsify hypothesis

Both these

hypotheses

are testable

The

Scientific Method

68

Deductive reasoning uses general premises

to make specific predictions

For example:

If organisms are made of cells (premise 1),

And humans are organisms (premise 2),

Then humans are composed of cells

(deductive prediction)

Deduction: The IfThen Logic of Hypothesis Based Science

69

24

A Closer Look at Hypotheses in Scientific

Inquiry

A hypothesis must be testable and falsifiable

Hypothesis-based science often makes use of 2 or more alternative hypotheses

Failure to falsify a hypothesis does not prove that hypothesis

You replace your flashlight bulb, and it now works; this supports the hypothesis that your bulb was

burnt out, but does not prove it (perhaps the first

bulb was inserted incorrectly)

70

o A controlled experiment compares an

experimental group with a control group

o Ideally, only the variable of interest differs

between the control & experimental groups

o A controlled experiment means that control

groups are used to cancel the effects of

unwanted variables

o A controlled experiment does not mean that

all unwanted variables are kept constant

Designing Controlled Experiments

71

72

A Case Study in Scientific Inquiry:

Investigating Mimicry in Snake

Populations

Many poisonous species are brightly colored, which warns potential predators

Mimics are harmless species that closely resemble poisonous species

Henry Bates hypothesized that this mimicry evolved in harmless species as an evolutionary

adaptation that reduces their chances of being

eaten

25

73

Fig. 1-25

South

Carolina

North

Carolina

Key

Scarlet kingsnake (nonpoisonous)

Scarlet kingsnake (nonpoisonous)

Eastern coral snake (poisonous)

Range of scarlet kingsnake only

Overlapping ranges of scarlet kingsnake and eastern coral snake

74

Field Experiments with

Artificial Snakes

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

An experimental group resembling kingsnakes

75


Artificial Snakes

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

A control group resembling plain brown snakes

26

(b) Brown artificial snake that has been attacked 76


Artificial Snakes Equal numbers of both types were placed at field

sites, including areas without poisonous coral

snakes

(a) Artificial kingsnake

77

o After four weeks, the scientists retrieved the

artificial snakes and counted bite or claw marks

o The data fit the predictions of the mimicry

hypothesis: the ringed snakes were attacked

less frequently in the geographic region where

coral snakes were found

o What do you think happened?

78

Fig. 1-27

Artificial

kingsnakes

Brown

artificial

snakes

83% 84%

17% 16%

Coral snakes

absent

Coral snakes

present

Perc

en

t o

f to

tal

att

ack

s

on

art

ific

ial

sna

kes

100

80

60

40

20

0

RESULTS

27

79

Questions That Can and Cannot

Be Addressed by Science o A hypothesis must be

testable and falsifiable

o For example, a

hypothesis that ghosts

fooled with the

flashlight cannot be

tested

o Supernatural and religious

explanations are outside the

bounds of science

Theories in Science

In the context of science, a theory is:

oBroader in scope than a hypothesis

oGeneral, and can lead to new testable

hypotheses

oSupported by a large body of evidence in

comparison to a hypothesis

80

81

Building on the Work of Others o Scientists check each

others claims by performing similar

experiments

o It is not unusual for different

scientists to work on the

same research question

o Scientists cooperate by

sharing data about model

organisms (e.g., the fruit

fly Drosophila

melanogaster)

28

Science, Technology, and Society

The goal of science is to understand natural phenomena

The goal of technology is to apply scientific knowledge for some specific purpose

Science and technology are interdependent

Biology is marked by discoveries, while technology is marked by inventions

82

o The combination of science and technology has

dramatic effects on society

o For example, the discovery of DNA by James

Watson and Francis Crick allowed for advances in

DNA technology such as testing for hereditary

diseases

o Ethical issues can arise from new technology, but

have as much to do with politics, economics, and

cultural values as with science and technology

o Many important inventions have occurred where

different cultures and ideas mix

o For example, the printing press relied on

innovations from China (paper and ink) and

Europe (mass production in mills)

o Science benefits from diverse views from different

racial and ethnic groups, and from both women

and men

84

The Value of Diverse Viewpoints in

Science

29

Themes That Unify Biology The overarching concepts of this class

1. The Cell-The basic unit of living things

2. Heritable Information- (in the form of DNA) Life continues because the information of How is passed to the next generation

3. Emergent Properties of Biological Systems- With each step up in hierarchy/complexity, properties appear that are not in any components

85

4. Regulation-Feedback mechanisms keep biological systems steady against changes

5. Interaction with the Environment-Living things exchange energy and materials with their environment (non-living & other living things)

6. Energy & Life-Energy is necessary to live, and passes from sunlight (usually) to Producers to Consumers

7. Unity and Diversity-Earth has many, many types of very different living things, but all share basic characteristics, which increase in number with close evolutionary relationships. 86

8. Evolution-Populations adapt to their environments, becoming different (Diversity), but keeping key characteristics (Unity).

9. Structure & Function-Go together at all hierarchical levels.

10. Scientific Inquiry-Science is advanced by observations and testing hypotheses and based on repeatability.

11. Science, Technology, & Society-Are intertwined and inseparable.

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chapter 1 gen bio

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