Diversity of Life

There is a better reason for studying zoology than its possible ‘usefulness’, and the inherent likeableness of animals.

- Richard Dawkins

Rene’ Magritte

J.S.G. Boggs

Marcel Duchamp

Understanding enhances appreciation: what will you think when you see

this?

There is a better reason for studying zoology than its possible ‘usefulness’, and the inherent likeableness of animals.

This reason is that we animals are the most complicated and perfectly designed pieces of machinery in the known universe.

- Richard Dawkins

Formula for success in this class

What is Biology ?

Biomolecules / Organic molecules

1. does irradiating food add radiation to food? Explain2. Describe the “octet rule”3. What are the two types of chemical bonds4. List at least 3 important properties of water5. Biological molecules are grouped into four categories. Name all four.6. Describe the difference between a monomer and a polymer; give an example of a

monomer and a polymer (your example does not have to be a biomolecule).7. Like all lipids, a triglyceride is insoluble in water because it lacks many fill in the

blank functional groups. Triglycerides are used for fill in the blank and are made from two subunits, a single molecule of fill in the blank plus three molecules of fill in the blank.

HydrophobicHydrophilicFatty acidsGlycerolAmino acidGlycogenLong-term energy storageQuick and ready source of energyStoring genetic informationMaking a phospholipid membrane

Biology is the science of life.

What is life?

Think of some examples…

No one mistook computer for life

So we have an intuitive sense of what we mean by “life”

What is life?

List “characteristics of living things”

What does “life” have or do that a computer does not?

List: Characteristics of Living Things

Organized: cells - tissues - organs - organ systems - organisms - population - community - ecosystem

Acquire material/energy

Maintain internal environment: homeostasis

Respond

Reproduce / Develop

Have adaptations

Really?

Let me challenge this a bit…try to get at the essence of “life”

What is “life” or “living”

Something that is organized ?

What is “life” or “living”

Something that is organized ?

What is “life” or “living”

Maintains status quo (homeostasis)?

Farmer fixing his fence (life), orHouse with AC/thermostat

vsBuffered lake (non-living)

What is “life” or “living”

Something that consumes energy ?

3Fe + 4H2O <-===-> Fe3O4 + 4H2Iron water iron (II,III) oxide hydrogen

What is “life” or “living”

Something that reproduces ?

What is “life” or “living”

Something that reproduces ?

What is “life” or “living”

Something that grows and develops ?

What is “life” or “living”

Something that responds to the environment ?

What is “life” or “living”

Something that has adaptations ?

Word-of-mouth stories

Definition of life:“I can not define it, but I’ll know it when I see it”

-Supreme Court Justice Stewart

“I can not define it, but I’ll know it when I see it”

Which one is “life”

“I can not define it, but I’ll know it when I see it”

Reproduce, utilize Energy (metabolism), adapt to environment…

require prolonged observation to determine, so

It becomes harder to distinguish life from non-life when it is from:

a long time ago (dead, fossil)petrified wood

another planet (E.T.) - potentially very different from us

shark tooth, sand dollar

Life on Mars?

Life on Mars?

Martian romantics

Life on Mars? Happy face!

Life on Mars?Life in extreme Earth

environments

Bacillus living at 55°C (131°F)

A novel thermophile

isolated from >300°C, 1500m deep, geothermal

water pool

Life on Mars -

fossils ?

From Martian meteorite

Bacteria (on Earth)

Size: 1 µm vs 0.1 µm

Are Martian fossils biological ?

Martian fossils:-Too small?-biological?

acid etches

Problems with listOrganized: cells - tissues - organs - organ systems - organisms

- population - community - ecosystemmost life is not multi-cellular

Acquire material/energy -

Maintain internal environment: homeostasis -

Respond what about a seed? Timescale of response

Reproduce / Develop can you do this by yourself?

Have adaptations -Require group of living things, often times different species (think of bacteria in you or a termite)

Definition of life:

“I can not define it, but I’ll know it when I see it”

-Supreme Court Justice Stewart

Maybe not so easy after all!

Symptoms of life:Order, reproduction, growth, development, energy utilization, response to environment

Symptoms of disease:1. fever is common early in the infection, aches and pains

throughout their bodies, cough, congestion, red or purple spot

on the body.

Influenza, virus2. In the first week, the temperature rises slowly and fever

fluctuations are seen with relative bradycardia, malaise, headache, and cough. Rose spots appear on the lower chest and abdomen

Typhoid fever, bacteria, from ingestion of food or water contaminated with the fecesof an infected person

Symptoms of life:Order, reproduction, growth, development, energy utilization, response to environment

Symptoms of disease:1. fever is common early in the infection, aches and pains

throughout their bodies, cough, congestion, red or purple spot

on the body.

Influenza, virus2. In the first week, the temperature rises slowly and fever

fluctuations are seen with relative bradycardia, malaise, headache, and cough. Rose spots appear on the lower chest and abdomen

Typhoid fever, bacteria, from ingestion of food or water contaminated with the feces of an infected person

Symptoms of life:

Order, reproduction, growth, development, energy utilization, response to environment

Underlying cause?(fundamental essence)

What distinguishes “living things” from

“non-living” chemical reactions?

“Living things” are different from “non-living things” because

living things can evolve ()

“living things” are a bunch of chemical reactions that:

can make copies of themselves (reproduce), and

the physical traits of the copies can differ from original

Why can the physical properties of “living things” change when “living things” are

copied (reproduce), but not so for “non-living” things?

The physical properties of “living things” are determined by a program

(indirectly), and this program can mutate when it

is copied

“Living things” are different from “non-living things” because

living things can evolve (physical traits can change over time)

)

“Living things” are different from “non-living things” because

living things can evolve (living things are the product of an

evolutionary process; “life” is a process that involves many

individuals over time)

“Living things” are different from “non-living things” because

living things can evolve (living things are the product of an

evolutionary process; “life” is a process that involves many

individuals over time)

biological evolution: living things direct their own

reproduction and living things encode their own

physical properties.joysticks do not make copies of themselves.we do it for them, and we determine their

physical properties

Let’s imagine anything that is alive: it can reproduce, and its physical

properties can change. Now…let’s add the environment. What happens

How many seeds does a dandelion produce?How many of these dandelions seeds live/grow and produce their own seeds?

Natural selection

1. The members of a population have heritable variations.

2. The population produces more offspring than the resources of an environment can support.

3. There is competition for resources; as a result, the better adapted individuals survive and reproduce more than the poorly adapted.

4. Across generations, a larger proportion of the population becomes adapted to the environment.

Ever heard that evolution is just a theory?

It turns out that evolution is fundamental to what we mean

when we think of life, of biology.

If it is not the product of evolution, it isn’t life.

anything that is life (evolves) will have some features in

commonReproduction - why must life reproduce? Nothing lasts forever: every machine breaks, or gets eaten, or gets hit by lightning… Spontaneous origins of complex things are rare, but “death and destruction” is not:

Imagine putting elements in a jar and shaking, or flipping a coin and getting ‘heads’ 1000 times in

a row…

Information molecule (program) that determines physical properties

and that can change/mutate/be copied.In our case, it is DNA (what do I mean by “our”?). Why must life have a program? Enables properties to mutate.

Consume Food: Why must life eat food? For energy and materials.

Necessary to maintain isolation/homeostasis/reproduction

Isolation from non-living environment: Cellswhy must living things be isolated from the

environment? Necessary to control chemical reactions, homeostasis

Essential to allowing competition, essential component of evolution

Heterotroph (Hydrogen; Hindendburg)

Natural Selection leads to Descent with

ModificationOnce you have life, and competition for resources, natural selection will lead a population to change over time.

Birds. Fig 1.11, page 9

Dogs (artificial selection)

Descent with modification can lead to new species

Living things are unique because they can evolve. This leads to descent with modification.

The life we see around us today is very diverse:How much of this diversity is the result of descent with modification?How many different times was life “created” from non-life?

“created” = “transition from non-living chemical processes to evolving processes”

Life does not violate laws of universe

(or require supernatural origins)Alcohol burns, a fire, releases energy. Just add a spark, and it

goessame process now as 100 million years agosame here as any planet

When you consume alcohol (ethanol), you burn it too…but it is burned in a specific way, a way controlled by your genes (DNA), a way that directs the energy release in useful ways (reproduction)

Imagine water running downhill, down a streamNow imagine rocks and branches falling down to obstruct the flowAlthough unlikely, the rocks and branches could fall in a way as to make a watermill, if organized in the proper way. It is not likely, but it does not violate the laws of the universe, require supernatural processes.

Everything around us is matter made of chemicals…series of chemical reactions…some of these chemical reactions create organization, reproduce, consume energy…all follow the laws of the universe, but some chemical reactions are controlled by a program that can mutate and reproduce… evolve… and this is what we mean by “life”

All dog breeds descended from one dog breed: wolves

All fish from one fish

All birds from one bird

All plants from one plant

All dog breeds descended from one dog breed: wolves

All fish from one fish

All birds from one bird

All plants from one plant

Even though fish and birds and wolves and dogs are very different, they still share a lot in common,

…what sorts of things do fish and birds have in common?

All dog breeds descended from one dog breed: wolves

All fish from one fish

All birds from one bird

All plants from one plant

Even though fish and birds and wolves and dogs are very different, they still share a lot in common,

suggesting they share a common ancestor, …followed by descent

with modification

All dog breeds descended from one dog breed: wolves

All fish from one fish

All birds from one bird

All plants from one plant

Even though fish and birds and wolves and dogs are very different, they still share a lot in common,

…what sorts of things do fish and PLANTS have in common?

Is there time for all this?

What is the age of planet Earth?Naturalists (like Darwin) saw patterns of

descent with modification that would appear to require a very long time…

…and Geologists saw patterns of erosion that suggest the earth is very old (much greater than 300 million years)

But, life on this planet requires energy from sun, andbased on estimates of:

the size of sun, distance of sun from Earth, the energy output from the best coal

imaginable…Lord Kelvin concluded the sun must be < 300 million years old.So life must be younger than this too!

All dog breeds descended from one dog breed: wolves

All fish from one fish

All birds from one bird

All plants from one plant

Even though fish and birds and wolves and dogs are very different, they still share a lot in common,

…what sorts of things do fish and PLANTS have in common?

All modern life on Earth is related by descent from a

common ancestor (evolution). Why do we believe this?

Because all life is descendent from one original life-form through an evolutionary process, we can work backward through time to modern life’s earlier and more simple form.

All life uses the same Biomolecules

(with few minor variations)Same 4 nucleotides in DNASame 20 amino acids in protein

A bit like people speaking the same language: clearly different languages can exist, so if we see people speaking English all over the place, we deduce the language derived from one source a long time ago, not that the same exat language was invented multiple times in multiple places

All life descended from

one common ancestor

Figure 1.4, page 6.

Three main branches (Domains)

When did this occur? And how do they know that?

Stromatolites: like microfossils of

early life

Modern stromatolites Ancient fossils (?)

Hadean Earth (Hell on Earth)

When did all this happen? Geological

timelineBillion years ago What was happening 15 universe formed in Big Bang 4.5 Earth formed 4.0 Heavy bombardment stops 3.85 Fossils evidence of life (?) 2.0 Fossils of eukaryotes (?)

0.5 multi-cellular life becomes abundant 0.05 dinosaurs go extinct 0.005 chimp/human diverge 0.0001 firs modern humans 0.00001 humans colonize Americas (Indians) 0.000005 ancient Egypt, Greece, Rome, etc 0.0000005 dark ages of Europe 0.00000005 your parents were born

Life started quickly (~200 my), but intelligent life came so late it might have missed the party all-together (human intelligence arrived after 4 by of evolution, with only another 1 or 2 by left before all life on Earth ends)

How old is the oldest fossil?

Tape measure:

25 feet = 2.5 billion years

1 foot = 0.1 billion = 100 million years

1 inch ~ 10 million years

1/8 of inch ~ 1 million years

width of hair (~1/1000 inch) = 10,000 years

When did all this happen?

4 3 2 1 todayTime - billions of years ago

Earth forms

Period of heavy bombardment

Carbon isotope (first evidence of life)

First fossil microbes

Oldest eukaryotic fossil

dinosaurs hominids

Animal diversity begins

Oxygen accumulates in atmosphere

Hadean Earth (Hell on Earth)

When did all this happen?

4 3 2 1 todayTime - billions of years ago

Earth forms

Period of heavy bombardment

Carbon isotope (first evidence of life)

First fossil microbes

Oldest eukaryotic fossil

dinosaurs hominids

Animal diversity begins

Oxygen accumulates in atmosphere

And what does it mean?

When did all this happen?

And what does it mean?All life on this planet is derived from just one “transition from non-living to living”

So maybe “origins of life” is very unlikely

On the other hand, life started quickly after earth cooled,So maybe it is not so hard…

But if it is not so hard, then why just once?Perhaps it happened fast because just the right conditions existed then, but not since then.…or perhaps there were multiple origins, and hence multiple, unrelated lifeforms form, but one was superior and out-competed (ate) the inferior one, causing all but one to extinction.

When will life on this planet end? While some forms of life went extinct, other forms have continued by adapting and persists.

So while life might persists once it forms, is it inevitable?We know when life started on this planet (rather

quickly). Maybe it would do so on other planets too.

Is “intelligent life”inevitable? Or even multi-cellular life?“Human intelligence” arrived quite late, almost missed

the party

Biomolecules / Organic molecules

1. does irradiating food add radiation to food? Explain2. Describe the “octet rule”3. What are the two types of chemical bonds4. List at least 3 important properties of water5. Biological molecules are grouped into four categories. Name all four.6. Describe the difference between a monomer and a polymer; give an example of a

monomer and a polymer (your example does not have to be a biomolecule).7. Like all lipids, a triglyceride is insoluble in water because it lacks many fill in the

blank functional groups. Triglycerides are used for fill in the blank and are made from two subunits, a single molecule of fill in the blank plus three molecules of fill in the blank.

HydrophobicHydrophilicFatty acidsGlycerolAmino acidGlycogenLong-term energy storageQuick and ready source of energyStoring genetic informationMaking a phospholipid membrane

You are what you eat!the four classes of

biomolecules

Nucleic acid (DNA, RNA)

Protein (amino acid)

Lipids (fat)

Carbohydrates (sugars)