EVOLUTIONEVOLUTION

Neanderthal Modern day humanHomo neanderthalensisHomo sapiens

If evolution was condensed into 1 day…..

yrs. yrs. yrs. yrs.

Evolution-

The theory of evolution suggests that organisms that exist today evolved from earlier, more primitive forms over a long period of time.

Evidence of Evolution-

1. Fossils- shows common ancestry among organisms~any remains or trace of a once- living organism~found in __________________rock*, ice, tar or amber

change in organisms over time

“the diversity of living things as well as their unity may be the result of evolution”

sedimentary

*sedimentary rock is a type of rock formed from layers of particles that settled to the bottom of a body of water, often containing fossils

~the ages of rocks have been determined by ___________________

~lower layers of rock contain _______________life forms

~upper layers of rock contain _____________________life forms

radioactive dating

older, simpler

newer, more complex

2. Comparative Anatomy- shows common ancestry among organisms

a. homologous structures- structures in various organisms that are similar in structure and origin but have different functions in each organisms

ex). whale flipper, bat wing and human arm

b. vestigial structures- structures that were once functional but no longer are. ex). appendix, tailbone, wisdom teeth

Discover 6/04

3. Comparative Embryology- shows common ancestry among organisms When you compare vertebrate___________

embryos, at some point in development, they all have similar appearances (gill slits, tails)

w/a backbone

Fish Salamander Tortoise Chick Hog Cat Rabbit Human

4. Comparative Cytology- shows common ancestry among organisms

~Cytology = _____________________~all living things are made of cells~all cells have similar organelles with similar functions

5. Comparative Biochemistry- shows common ancestry among organisms

~all living things contain similar compounds _________________________________~the closer the relationship between organisms, the greater the similarity of their chemicals (humans can use insulin from sheep and pigs!)

the study of cells

enzymes hormones DNA glucose

Theory of Spontaneous Generation

Idea that living things could arise spontaneously from things like mud, sweat, decaying meat.

A relatively simple sketch of Redi's experiment regarding spontaneous generation. Starting from the left, the first flask is capped, and no maggots grow within it, then in the second flask flies are kept out, but the mesh allows maggots to grow within, and finally flies are allowed into the third flask where maggots grow.

Redi disproved this theory.

THEORIES OF EVOLUTION

b. Theory of Acquired Characteristics- He believed that traits acquired in a lifetime are passed on to offspring (like my acquired taste for chocolate!)

1. Jean Baptiste Lamarck-a. Theory of use and disuse- “use it or lose

it”. He theorized that if you need a structure and use it , it will become more developed over time. Likewise, if you no longer need a structure (appendix, tail) and stop using it, it will decrease in size, become non-functional or disappear.

2. August Weismann-

disproved Lamarck's theory of acquired characteristics. His experiment: he removed the tails of mice, mated them and all of the offspring HAD tails!

Other examples that support Weismann:dog breeds with clipped tails and ears, circumcision

3. Charles Darwin- theorized that evolution occurred as a result of Natural Selection.. The main points of his

theory:

a. overproduction-

b. competition-

c. survival of the fittest-~variations among individuals make

some better adapted or more “fit ”

~the “fit” survive because they are best adapted to the environment

~(the “fit” are not necessarily the strongest)

most species produce more offspring than can survive because of limited food and space

overproduction leads to a struggle for available food, water, space and mates

Look at these examples of “fit” organisms: leaf fish, frog, spider, ptarmagin

e. speciation-

d. natural selection-

An older Darwin

nature “selects” organisms with optimal traits (the “fittest”) to survive and be the parents of the next generation.

This next generation will inherit the favorable characteristics that enabled their parents to survive & reproduce

when a new species arises with helpful variations/adaptations that have accumulated over many generations

Survival of the fittest……this tree has adapted to grow on the side of a hill (Thatcher Park, 9/05)

MODERN THEORY OF EVOLUTION

a. Today’s theorists accept Darwin’s ideas of natural selection, BUT Darwin’s theory DID NOT address how variations arise in a population.For example, why do some giraffes have long necks and some have short ones?

The answer is from gene mutation and random recombination of genes during _________________

The same thing goes for humans. We’re all different because of mutations and combination of genes from our different parents.

fertilization

b. natural selection: nature has selected the fittest organisms in the following instances:

~insects that are resistant to pesticides (are fit enough to survive and reproduce)

~bacteria that are resistant to antibiotics (are fit enough to survive and reproduce). You’ve all probably been on

antibiotics and have noticed that you’ve taken different brands. That’s because the bacteria build up a resistance to the old

antibiotics.c. Geographic Isolation-

~small population becomes isolated (mountain range, body of water, Pangea)~they adapt to their new environment and become so

different that they can no longer interbreed with the original population

~this inability to breed with the original population is called ________________________________~over time , this leads to

speciation:_____________________________ ex). Darwin’s finches on the Galapagos Islands

reproductive isolation

the development of a new species

d. Rate of Change- there are 2 different theories on how long it takes for evolution to occur:

1. Gradualism- evolution occurs gradually, slowly and continuously

2. Punctuated Equilibrium- when species have long periods of stability and then have sudden, brief intervals of major change.

Gradualism

PunctuatedEquilibrium

II. The Heterotroph Hypothesis...how did life begin on earth???

primitive inorganic materialsconditions “hot, thin soup”:

gases: -NH3 (ammonia)-CH4 (methane)-H2 (hydrogen)

sun and lightning provided the ENERGY needed to

SYNTHESIZE materials

small organic molecules formed (sugars, amino acids)

Stanley Miller reproduced this theory in his lab

sun, lightning and energy=

SYNTHESIS

****

Video clip, S. Miller’s expt

15 mins

large organic molecules were formed (proteins, carbs)

Sidney Fox reproduced this theory in his lab

large molecules clumped together

aggregates (colonies) were now presentThese were heterotrophic (no CO2 available)

they reproduced!

these aggregates are now considered ALIVEBECAUSE THEY CAN REPRODUCE

no free oxygen

these heterotrophs were anaerobic

heterotrophs produced CO2 during respiration/fermentation

photosynthesis now possible

autotrophs evolved

produced oxygen

aerobes evolved

Quick Summary

Heterotrophs CO2 given off autotrophs aerobesanaer.resp

photo-synthesis

O2 produced

(fossils, comparisons)

(simpler)

(mutation & crossing-over)

survival of the fittest

you cannot inherit acquired characteristics

An increase in biodiversity increases the stability of an environment

Pine bush, rainforest

evolution

fossils

comparative biochem

homologous

vestigial

Darwin

Lamarck

speciation

gradualism

punctuated equil.

reproductive

geographicspontaneous generation

Origin of life

aggregate

O2

photosyn

They were anaerobicrespiration or ferm

sun, lightning,radiation

All living things have the potential to carry out life functions. This is one fact that unites living things.

But, living things are not the same. There are billions of different living things. How do we tell them apart? How do we keep them organized?

Notes:

The Unity and Diversity of Living Things

Biological Diversity (don’t put in notes)

Edward Wilson, 1999

The total # of kinds of plants, animals and microorganisms known to science (those which have a scientific name) is about 1.4 million. But, the actual # is estimated to be between 10 and 80 million. “We don’t know even to the nearest, the amount of diversity in the world.”

Out of the 1.4 million named organisms, there are approximately

750,000 insects

242,428 plants

123,151 arthropods

46,983 fungi

19,056 fish

9,048 birds

4,000 mammals

Humanity is creating a radical new environment too quickly to allow species to adjust. Species need thousands of years (maybe millions) to assemble complex genetic adaptations. Most of life is consequently at risk (of extinction)”

……this is why human impact is directly related to the environment.

Now, back to notes….

The Diversity of Life

In order to study the billions of living organisms, scientists need to have an organized system: a classification system.

Plant Animal

Taxonomy is the branch of Biology that studies classification.

Hundreds of years ago, scientists classified living organisms into 2 groups called kingdoms.

But, they kept discovering organisms (ex. mushrooms) that didn’t fit into either kingdom.

Today, we use a 5 kingdom classification system:1. Monera2. Protista3. Fungi4. Plant5. Animal

But, even these groups are too broad to have an organized system so the kingdoms are broken down into smaller & smaller groups:

KingdomPhylumClassOrderFamilyGenusSpecies

How do we place organisms in the proper K,P,C,O,F,G,S?

We examine them and group them according to the following:

Broadest, largest group

Smallest, most specific

(hint: species~specific)

1. evolutionary relationships (did they come from the same

ancestor?)

2. the presence (eukaryotic) or absence (prokaryotic) of a

nuclear membrane within the cell.

3. unicellular or multicellular?

4. type of nutrition (heterotrophic or autotrophic)

Kingdom Characteristics Examples

Monera

Protista

•most primitive kingdom•lacks a nuclear membrane

(prokaryotic)•some organelles

•bacteria

•blue green algae

•mostly unicellular•eukaryotic

a. protozoa

b. algae

heterotrophic

autotrophic

parameciumameba

spirogyra

Kingdom Characteristics Examples

Fungi

Plants

•Eukaryotic•Multicellular

•Have branched filaments called rhizoids (like roots) that secrete digestive enzymes into the surface that the fungi is on. The fungi then absorb the digested material•heterotrophic

mushroom

yeast

bread mold

athlete’s foot fungus

•multicellular•photosynthetic•autotrophic

a. Bryophytes lack vascular tissue (xylem, phloem)have no true roots, stems, leaves

moss

do have vascular tissue and trueroots, stems, leaves

fern

water lily

sycamore tree

b. Tracheophytes

see next slide

pores

hydra

jellyfish

sponges

•hollow body cavity•2 cell layers

trichinahookwormheartworm

flatworms

earthworm

leech

•round worms•parasitic

segmented worms

planariatapewormliver fluke

bees, beetles, cockroaches

no shell: slug, octopus, squid

lobster, crab, shrimp

2 shellsclams, oysters

1 shell: snail

exoskeleton (chitin)

starfishsea cucumber

brittle starsea urchin

spiny skinned

endoskeleton

dorsal nerve cord

many including:

reptiles

birds

mammals

soft-bodied

spiders, scorpions

millipedes : 600 legs

centipedes: 60 legs

jointed appendages

prokaryote eukaryote………………………………………..

hetero but

chemosyn in archaebact

nono

hetero auto hetero auto hetero

yes no noyes

uni multimultimultiuni/

colonyuni

bacteria,blue-greenalgae

ameba,

parameciumspirogyra

mushroom

bread mold

fern

tree

human

dog

Scientific Naming

There is a naming system called binomial nomenclature

two name

naming system

Just like we all have a first and a last name, so do organisms.

Scientists refer to organisms by their genus (1st name) and species (2nd name)Ex). Felis domesticus = common house cat

genus species

Rules for using scientific names:

1. Genus is always capitalized

2. Species is always lower case

3. Both words are either underlined or italicized

Note: a species is defined as a group of organisms that can mate and produce

fertile offspring

G

s

3

11

89

6

1

7

210

4

5

coccus

Bacillus botulinum

Bacillus

Organizes by structure, shape, arrangement

Diplococcus pneumonia

strep

diplo

Bacillus anthracisBacillus tetani

Dipteron cyclopsHelikopteron bacillus

Podus cyclops Helikopteron coccus

Podus monoantennaePodus anoculusPodus biantennae

Sessilis aquatilis

Dipteron polyoculusSessilis terretris Podus triantennae