Evolution Chapter 3

Burgess Shale number of species found?

93+ species -died 505 mya -largest species discovered recently. -Bank collapsed> flung into )2 free abyss.

oldest homo sapien fossil

<200,000 years old, found in Ethiopia.

Before rise of teleosts, oceans top predators were....

giant sea scorpions. 6 feet long.

The famous bacterium, Thermus aquaticus,

he original source of thermostable DNA polymerase (Taq polymerase) used in PCR.

It appears plants and fungi....

helped each other evolve onto land.

species more closely related to humans than chimps

hominins, early ones similar to chimps in body and brain size.

What was important about the Late Heavy Bombardment?

icy comets and asteroids delivered water to the early Earth

Animals in North America thousands of years ago;

lions, rhinos, camels, mastadons, mammoths. and beavers (extinct)

Viruses can be very complicated and contain

many genes that encode proteins and elaborate structures.

How do we know archaea were also present at beginning of earth?

methane in rocks, with low fraction of carbon (produced biologically).

Each of the the domains (Bacteria, Archaea, and Eukarya) is thought to be

monophyletic.

range of uranium-lead dating

more than a million years.

Kimbrella

multicellular organism, Edicaran Fauna, rasp-shaped structure similar to modern mollusks for eating.

hydrothermal vent precipitates

must be alkaline, possibly oldest forms of life. Possible source of origin of life.

abiogenesis (spontaneous generation)

natural process, life originates from inorganic (nonliving) matter.

Wattieza

oldest tree-like plant. 385 million y/o. Stood 8 meters tall.

Endosymobiosis

organelles were once free-living bacteria that were incorporated into a larger eukaryotic cell

Age of cyanobacteria close to oldest evidence of ;

oxygen in fossil record (produced O2 during photosynth)

Archaea are not

photosynthesizes

Lipid biomarkers extracted from organically preserved Ediacaran macrofossils unambiguously clarify their

phylogeny. Dickinsonia and its relatives solely produced cholesteroids, a hallmark of animals.

Evolution of lignin and other tough plant compounds allowed what?

plant lineages to grow; stems, stalks, and trunks.

Fossils of what are over-represented in the La Brea Tar Pits?

predators; Some predators may have been trapped as they tried to drink or bathe, but most were likely trapped because they tried to feed on dead and dying animals that were already trapped. (Golden Eagle, Dire Wolf)

Climactichnites

probable trackways from slug-like animal

Bacteria and Archaea are both

prokaryotic; cells lack a nucleus. dna is one big loop, not contained

Argument of what good is half an eye is example of....

red herring

After volcanic ash

resets radiocarbon clock to zero.

Radiometric dating starts when....

rock cools and becomes solid.

Age of Earth

rounded off to 4.5 billion years.

542.68 ± 1.25 Ma (terminal Ediacaran)

sediment bulldozers... i.e. actively moving around.i.e. not passive filter-feeders or passively photosynthetic.

Chengjiang fossil deposit

similar fossil in china to burgess shale

Platyhelminthes

simple eyes

Plasmids

small circular DNA molecules that replicate separately from the bacterial chromosome (sattelite loops of DNA) for horizontal transfer > resistance(antibiotics)

Meterorid

small pieces of asteroid broken off from collision.

hominim walking on shore note;

some fossils are mineralized (petrified) but others are not.

Carbon-14 (8 neutrons) is unstable (too many neutrons) and will eventually decay to

stable nitrogen-14.

Chondrites are

stony meteorites composed of rounded grains, flakes of metal, and rocky bits.

zircons are actually older than the oldest known intact

surface crustal rock formations on Earth. Zircons (4.4 bya) oldest known rocks (4 bya)

Mammals are descended from sprawling, reptile-like vertebrates called

synapsids that first emerged 320 million years ago.

Sahelanthropus

the first known bipedal hominin. 7mya

monophyletic

the members of each domain traces back to a single common ancestor (long extinct).

Late Heavy Bombardment

time during Earth's early history when the planet was impacted by many collisions> bringing water and possibly microbes! 3.8 billion years ago. Still seen on moon but not on Earth (movement of tectonic plates, erosion, weather).

Snails (mollusks) eyes

tiny eyespots at end of eye stocks, not perceiving image, detect light/dark, and movement.

Eukaryans can be

unicellular or multicellular.

Bacteria and archaeans are

unicellular.

Range of radiocarbon dating

up to 50,000-60,000 years

Range of Uranium-Thorium Dating

up to about a million years

K-Ar dating range

up to billions of years

argon-argon dating range

up to hundreds of millions of years

Tetrapods

vertebrate animals having four feet, legs or leglike appendages

The first "eyes" were not eyes as we know them, but _____.

very simple, clusters of photosensitive cells, -benefit; tell light vs dark, allowing movement either toward/away from light (hiding places/ vertical migration) Avoiding UV near water surface.

If we descend from archaea then we really are;

walking consortia of prokaryotic cells that evolved.

cells existing before the 3 groups

we presume that LUCA and her descendents must have eaten them or outcompeted them and thereby eventually driven them to extinction because all known cells have fundamental similarities

Fossil

"A mineralized remnant of an organism preserved in rock". this is an oversimplification.

Some scientists would prefer to use the term ______ when describing remains or traces* that have not been mineralized (or mineralized yet).

"subfossil"

1.07% of carbon atoms have 7 neutrons

(aka carbon-13).

One carbon atom in a trillionhas 8 neutrons

(aka carbon-14).

So what do scientists use instead to date the exact age of Earth?

*this is why scientists use the ancient meteorites.

Early Life timeline

-3.5bya; rocks show methane with low carbon 13 (archaeal). -3.45bya; stromatolites resemble living bacteria. -2.6bya; microbial fossils resembling cyanobacteria. (photosynth) -1.8bya; unicellular eukaryotes.

Complex eye structure evolved independently in several groups independent groups and only homologous within those groups.

-Mullusca -Annelida -Arthropoda -Vertebrata (us)

Using lead-lead dating, the oldest known rock in the solar system (from the meteorite Efremovka) was measured to be

4567 million years old = 4.567 billion years old. (same time earth forming)

The half-life of carbon-14 is

5,730 ± 40 years.

Carbon-14 dating is limited to dates less than

50,000 -60,000 years.

Giant Beaver

-size of a bear -hung around lakes, marshes etc. -herbivore 18,000 yearsago

How can fossilization fail?

-skeleton trampled, sun-beaten, rain-soaked, nothing left to fossilize. -After formation; pressure, heat, erosion from wind/rain.

How does oxygen level in bones relate to whale species?

1) Pakicetus; still drank fresh water. LOW O2 2) Ambulocetus; Brakish water near shore or mix of fresh/seawater. INTERMEDIATE O2 3) More recent fossils; drank seawater. HIGH O2 (Species went from land> estuaries> open ocean)

Evidence for the endosymbiotic origin of organelles we call mitochondria and chloroplasts. Prokaryotes > Eukaryotes.

1) Same size range as free-living prokaryotes. 2) Susceptible to abx that kill prokaryotes. 3) separate circular genome. 4) Ribosomes similar to prokaryotes. 5) Gene organization similar. 6) divide by simple binary fission. 7)inner membranes similar.

Fundamental similarities of cellular life on Earth

1. a universal genetic code based on DNA , nucleotides, amino acids, and RNA. 2. mRNAs are translated to proteins by ribosomes via tRNAs (transfer-RNAs), 3. energy metabolism is based on glucose (D-isomer only) and ATP (adenosine triphosphate), 4. numerous universal proteins and enzymes e.g. actin (MreB), 5. phospholipid bilayer membranes 6. universal ion pumps (sodium at low concentration inside cell and potassium higher)

Where did viruses come from? There are currently three main ideas:

1.Evolved after origin of life and represent remains of degenerate cells. 2.Evolved after the origin of life and evolved from modified plasmids. 3.Viruses coevolved with the first cells.

According to Nick Lane, all free-living cells combine six properties:

1.carbon capture 2.energy transduction 3.heredity 4.metabolism 5.compartmentalization 6.excretion

Lake Michigan stromatolites dated...

2.2 billion years ago.

age of stromatolites

3.45 billion years

The Late Heavy Bombardment happened how long ago?

4.1 to 3.8 billion years ago.

Oldest evidence of animals that can move.

585 million y/o tracks in fossil by small worm-like organisms.

Planarian

A free-living flatworm found in unpolluted ponds and streams. (KInni) Simple eyes. Scavengers.

lead-lead dating

A radiometric age dating technique that relies on measurements of two different isotopes of lead produced from two uranium isotopes that have different half-lives.

Kuiper Belt

A region of the solar system that is just beyond the orbit of Neptune and that contains small bodies made mostly of ice

Oort Cloud

A spherical region of (billions of comets) that surrounds the solar system

When did eukaryotes emerge in fossil record?

About 1.8 billion years ago. (single celled organisms)

Age of the Universe (know for test)

About 13.8 billion years

How is a fossil created?

After skeletonization, portions buried in sediments and ash. Water percolating through sediment pores delivers minerals to fill latticework of bone/shell. Becoming rock/fossil.

Edicaran biota

An early group of macroscopic, soft-bodied, multicellular eukaryotes known from fossils that range in age from 635 million to 535 million years old.

viruses are neither cellular nor free-living. They are cellular parasites i.e. they need a cellular "host" to grow and reproduce.

And yet viruses can evolve via natural selection if they occur as variable populations.

How can we use oxygen levels to determine organism environment.

Animals that lived on have oxygen from freshwater in bones. Marine animals have "heavier" oxygen from seawater in bones.

Three main groups of tree of life.

Archaea Bacteria Eukarya

As far as we know, there are three main lineages of living cells on planet Earth:

Bacteria, Archaea, and Eukarya

Earliest members of many living groups of animals first appeared during what?

Cambrian period.

Bacteria

Can survive almost anywhere. May be shaped like rods, filaments, or spheres. Some carry out photosynthesis. Traits not in euk/archa: Membrane partially constructed by peptidoglycan.

Burgess Shale

Canadian fossil formation that contains Cambrian soft-bodied organisms as well as organisms with hard parts. Preserved because mudslides sent organisms into oxygen-free abyss where bacteria could not decompose bodies.

large plant species began to appear in what period?

Carboniferous period. Ferns and gingko trees still exist today. Flowering plants then more favored.

Chondrites contain what

Contain chondrules; (round things in meteorite) believed building blocks of formation of chondrules, allows for dating.

How did earth look 1.5 billion years ago?

Desolate; no trees, flowers, moss, no marine animals or coral. Just microbial life.

Lynn Margulis

Developed the Endosymbiotic Theory. Punished by establishment; no one believed her. Mitochondria from non-mitochondria. The Origin of Mitosing Eukaryotic Cells

How do scientists distinguish between two sources of carbon?

Due to biology's preference for lighter carbon isotopes.

Oldest recognizable multicellular eukaryotes?

Filaments of algae, 1.6 billion y/o. Before that; unrecognizable disks.

Thomson (lord) Kelvin; what was his critic of Darwin?

Earth could not be that old. "Proven" by temperature of the Earth and how long it took rocks to cool. He was wrong.

Rise in oxygen level likely due to.....

Emerging cyanobacteria, which release O2 during photosynthesis. Still much lower levels today so purple sulfur bacteria could still thrive.

Only one group of organisms living today produce methane...

Euryarchaeota, descendent of archaea. live in cows GI tract.

Evidence that architecture of eukaryotes was;

archaeon

Edicaran Fauna

First evidence of multicellular organisms. Bottom dwelling marine animals that lived late in the Precambrian time. They might have been similar to modern jellyfish, worms, and soft corals but with tough outer coverings. Before Cambrian period.

size variation of viruses

Giant viruses can actually be larger than some small bacteria.

What happened after sun first formed?

Gravity caused dust to clamp together into small bodies (planetesimals) that collided to form planets.

Earliest signs of life likely from what?

Photosynthetic bacteria; producing carbon isotopes.

Eukarya

fusion of bacteria and archaea >LUCA predates that

Eukaryotes

Include multicellular lineages, animals, plants, fungi, and mostly single celled organisms (protists) like amoebae. Much larger than the other groups and contain a nucleus. (some have mitochondria). Sponges

Octopus eye superior?

Independent evolution of the "camera eye". There is a "blind spot" in the human eye... but not in the eye of an octopus. This is due to an ancient evolutionary constraint in vertebrates. -Independent evolution of the "camera eye". There is a "blind spot" in the human eye... but not in the eye of an octopus. This is due to an ancient evolutionary constraint in vertebrates.Note that the optic nerves are exterior in the octopus eye but interior in the human eye.

flowering plants emerged in what period?

Jurassic/Cretaceous. Likely thanks to rise in beetles and other insects.

Name of common ancestor for 3 groups

LUCA-which stands for the Last (most recent ) Universal Common Ancestor.

LUCA

Last Universal Common Ancestor. The shared ancestor that multiple organisms diverged from

Source of carbon before life began.

Lifeless sources; volcanoes. then after life, abundant organic carbon from living sources> gradually incorporated into sedimentary rocks.

Archaea

Like bacteria; single celled, May be shaped like rods, filaments, or spheres. Unlike bacteria: No photosynthesis, distinct proteins that transcribe DNA to RNA. Eukaryotes evolved from archaea?

During Earth's first 3 billion years, life remained mostly....

Microscopic

Zircons

Microscopic crystals/minerals; holding tiny specs of carbon. Info from balance of carbon isotopes. Only traces of crusts first few hundred million years. Do NOT preserve fossils, but a chemical snapshot of time of creation.

Oldest known fossil of fully terrestrial animal is ancestor of what animal?

Millipede

What happened when Earth formed 4.57 billion years ago?

Molten> cooled/hardened (millions of years)> rock formations first continents> gases escaped from rocks creating atmosphere> water from comets/asteroids created oceans> collision creates moon> crust breaks (tectonic plates, billion years)> lava rose adding to margins> collision/burial swept away most of original surface.

Earliest land plants resemble...

Mosses and liverworts.

Are all fossils petrified?

NO

Are evolution and origin of life the same thing?

NO, evolution requires populations to evolve.

Are amino acids only from biologic sources?

No many chemical reactions produce them.

Is evolution entirely random?

No only partially

are tarpit fossils mineralized?

No petroleum covered. REAL bones.

Can amino acids be made into proteins without biology?

No, needs enzymes produced by organisms.

Presence of purple sulfur bacteria means what?

Oceans likely toxic to us anyways at time. Found only in extreme, low oxygen, high sulfur environments.

How can scientists infer type of organisms that left biomarkers in rock? example....

Okenane, red pigment made by purple sulfur bacteria in 1.6 billion y/o rock. We know because no reactions known that can make this pigment w/o bacteria.

Stromatolites

Oldest known fossils formed from many layers of bacteria and sediment.

Silvanerpeton

One of the oldest terrestrial vertebrates (tetrapods).

In what is now called North America, there were at least two different beaver species that are now extinct:

Paleocastor (Corkscrew Beaver) and Castoroides (Giant Beaver).

How can we use carbon levels to determine diet of fossil?

Plants have different carbon ratios based on photosynthesis. This is incorporated into cells of animals that ingest it. This level of carbon reflects diet.

plasmids > viruses?

Plasmids found i antarctic salt lake acting like viruses (viruses evolved from plasmids?)

La Brea Tar Pits who was at risk?

Predators and social animals.

elliptical plane

Remember that the sun and planets formed out of a gravitational collapse (condensation) of gas and debris in the pre-solar nebula

Early eukaryotes had....

Ridges, Plates, and other structures similar to current single-celled organisms.

Oldest known bipedal hominoid.

Sahelanthropus

convergence eye evolution

Simple corneal eye (no lens, curved cornea); arachnids, some vertebrates and larval insects. Simple lens eye (curved cornea and lens); vertebrates, arthropods, humans, jellies, annelids, at least one crustacean. Compound eye; insects, crustaceans, some mollusks, and annelids.

What may be the oldest lineage of living (animals)?

Sponges

Earliest appearance of animals in fossil record was what animal?

Sponges, left isolated cholesterol-like molecules similar to modern sponges in rock.

Most fish belong to which group?

Teleosts

541.0 ± 1.0 million years ago something really big started to happen.

The Cambrian "Explosion" of creatures with "hard parts" i.e. exoskeletons. Apparently predation had increased as an evolutionary pressure. Selection was favoring armor.

Burgess Shale Fossil Deposit (Canada)

The Walcott fossil quarry currently sits at an elevation of 7500 ft (2286 m) above sea level. Originally the dead animals were deposited on a deep ocean abyssal plane (far below sea level).

Why did animals enter the La Brea Tar Pits?

The pool of viscous, sticky tar was sometimes covered by a thin layer of rain water. This water would have attracted both predator and prey species.

cistern spring where they first collected...

Thermus aquatacus

Arthropleura

This (GIANT) *enormous millipede* was the *FIRST ARTHROPOD ON LAND*. Fossils from the Carboniferous period show track imprints of their feet. *-BIGGEST terrestrial millipede.* vegetarian

Anomalocaris

an unusual critter in the Burgess Shale, also known as the "terror of the trilobites"; world's first ferocious predator, great white shark of the Cambrian oceans

Between 635-575mya what happened?

We start to see fossils of larger, complex multicellular creatures during the Ediacaran. This was toward the end of the Proterozoic of the Precambrian.

How do vertebrates walk?

With alternating gait.

oldest known surviving solids on Earth

Zircons

meterorite

a meteoroid that does not completely burn up in the atmosphere and strikes the surface of a moon or planet

Premineralization

a process of fossilization which deposits from internal casts of organisms. *can happen in tissues like wood, bone, and shell...

Panspermia

a theory that life did not originate on Earth but arrived in the form of bacterial spores or viruses from an extraterrestrial source. (possibly comet/asteroid)

If a rock melts then our ability to date it is lost, why?

because the various isotopes (products of radioactive decay) must be trapped in solid rock for dating to work.

Why is it difficult to know exact age of Earth using Earth rocks?

because there are apparently no rocks left from the original accretion- they have all been secondarily melted

The asteroid belt is located

between the orbits of Mars and Jupiter

Jupiter =

big vacuum cleaner. its orbit steers things away from our planet.

Rubidium dating

can date things much older half life is a billion years

if an atom has 6 protons then it is

carbon

98.93% of carbon atoms on Earth have 6 neutrons and are called

carbon-12 (6 protons + 6 neutrons = 12).

a new organic material (if it contains carbon), e.g. newly formed bone, hair, wood, amber, etc. will have a consistent starting ratio of carbon(______)?

carbon-14 to carbon-12. -But this will change over time in a clock-like fashion.

Of all living primates human's closest relatives are....

chimpanzees and bonobos.

solar system dated using meteorites called;

chondrites

most meteorites classified as;

chondrites; stony meteors

Lineage humans belong to from Cambrian period.

chordate. Traits; brain, arches that may have supported gills.

Straw Man Argument

create false target and attack it, distracts from real issue,

why mammals from synapsids?

diverse dentition (reptiles don't)

Synapsids

dominant, sprawling, reptile-like vertebrates before animals even resembled mammals. Early ancestors of mammals

Mummification can result from any conditions that prevent decay

e.g. freezing cold, acidity, or dehydration.

If the age of the Earth is represented as a single hour, then the Cambrian "explosion" happened

eight (8) minutes ago.

planets orbit sun in

elliptical plane

Animals, plants, and fungi are all

eukaryans. But so are lots of tiny unicellular creatures.

Eukaryan cells are

eukaryotic i.e. cells have a nucleus. (membrane bound)

Paleocastor (Corkscrew Beaver)

extinct, corkscrew burro

Zircons are

extremely durable crystals of ZrSiO4(zirconium silicate). They are so durable that they can even survive moderately hot melting of surrounding rocks!

Thermus aquaticus is an

extremophile but it is not an Archaean. Domain: Bacteria (aka Eubacteria)

Omuamua

first recorded interstellar object (from another solar system) Over 4 lightyears away. second one (Borisov) seen in 2019, NOT same one.

Example of mineralized subfossil?

footprints

How did elliptical plane form solar system?

formed out of a gravitational collapse (condensation) of gas and dust within a molecular cloud (aka stellar nursery) into a pre-solar nebula, which then started to rotate faster and faster (via conservation of angular momentum) until it flattened out as a protoplanetary disc. The sun, planets, etc. eventually formed by accretion within this disc.

Consider an insect or spider or leaf or feather, trapped in amber. The trapped body or body part is not mineralized. Yet it is still considered a

fossil.In amber, resins prevent bacterial decay and the trapped object slowly dehydrates.The trapped body or body part is mummified.

First eukaryote

free-living bacteria evolved by endosymbiosis into organelles i.e. mitochondria and chloroplasts. This allowed for the evolution of eukaryotes and then large complicated multicellular creatures... like us.

red herring fallacy

when a speaker introduces an irrelevant issue or piece of evidence to divert attention from the real issye (conscious/unconscious) *developed from dragging red herring to distract hunting dogs.

Why is it important that our mitochondrion are bounded by—not one—but two phospholipid bilayer membranes.?

when you take antibiotics to control a bacterial infection, it is the outer membrane that shields your mitochondria

Chengjiang deposit has produced about twice as many species

with over 180!...

Is death an adaptation

yes, room for new individuals, turnover of individuals> evolution.