Evolution Test #1
Fossil
"A mineralized remnant of an organism preserved in rock". this is an oversimplification.
Homo erectus
"Upright man" these hominids became skillful hunters and invented more sophisticated tools for digging, scraping and cutting. They also became the first hominids to migrate from Africa. Also were the first to use fire. -taller, larger brain that older ancestors, 2x chimp-size. Flatter face, slender arms and legs.
"apo" means
"away from" i.e. away from the original character state.
Pakicetus is always
"basal" (the oldest node). Then Ambulocetusis next, then Dorudon, and then the extant whales.
Pseudogenes are heritable
"fossils". can and have been used in phylogeny reconstruction!
transposons (jumping genes) can actually instantly
"knockout" a gene (resulting in a nonfunctional genes). If in germline cells> heritable.
Note: the gibbons are sometimes called the
"lesser apes"; the remaining four taxa are the "great apes".
In a phylogenetic analysis, the goal is to find the most
"parsimonious" tree.
A cladogram is a phylogentic tree that is
"rooted" on an outgroup.
Some scientists would prefer to use the term ______ when describing remains or traces* that have not been mineralized (or mineralized yet).
"subfossil"
Ambulocetus
"walking whale" -Legs stubby -Rear feet shaped like paddles. -Head long like alligators. -Teeth/involucrum like whales.
The earliest known fossil bat
(Onychonycteris) resembled modern old world fruit bats aka flying foxes (megabats).
1.07% of carbon atoms have 7 neutrons
(aka carbon-13).
One carbon atom in a trillionhas 8 neutrons
(aka carbon-14).
Somatic mutations
(in any other cells) are not inherited*. -Mutations related to environment.
Germ-line mutations
(leading to sex cells e.g. eggs and sperm) can be inherited.
convergence
(parallel evolution) Pinnipeds; (seals, walrus) evolved from terrestrial ancestor. Evolved aquatic traits SEPERATELY from whales.
mobile genetic elements
(transposons)aka "jumping genes". Parasitic; w/o function but interupts/kills genes. And can copy and paste.
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.
convergent Adaptation of gliding in what species
-American flying squirrel; NOT involving ribs. Tail is free. skin between limbs (patagium). -Red Giant Flying Squirrel note: much of the tail is free. -Australian "flying" possum aka Sugar Glider. Tail free. -The Colugo aka "flying" lemur (note: not a lemur) Tail webbed (added patagium to tail)
Closest aquatic relatives of tetrapods.
-Coelacanths; stout bodies fish. (Eusthenopteron) -Lungfish
How do we know that traits are homologous?
-DNA -morphology -developmental biology
Australopithecine africanus
-Like apes; snouts, chimp-sized brains, similar weight, curved toes and fingers, arms long, ankles could rotate more freely than ours.
Three living Branches of mammals
-Monotremes; platypus, echidna. Produce milk through network of glands, not a nipple. lay eggs. (Mammals that bear live young "therians" other 2) -Marsupials; opossums, kangaroos, koala. pouch for babies, -Eutherians; humans, placentas.
Complex eye structure evolved independently in several groups independent groups and only homologous within those groups.
-Mullusca -Annelida -Arthropoda -Vertebrata (us)
Prokaryotic cells
-No nucleus -DNA spans cytoplasm -Organized 1 circular chromosome -Plasmid carry additional DNA -control gene expression with regulatory elements -Only exon -Plasmids
What did Buffon recognize?
-World made up of minuscule particles> -Particles reacted with each other according to certain laws> -When brought together with larger objects, larger objects also followed those laws.> -Objects attracted to each other by gravity> -Objects attracted/repelled by electric charge> -Following laws particles moved and complexity of universe emerges spontaneously.
6 Animals that share homologous arm bone structure with humans
-cat, whale, bat, dog, horse, bird, seal.
Proteins
-chains of amino acids. -sequence of amino acids determined by DNA. -Chains made in ribosomes.
Levels of chromosomal organization
-chromosome -super coil -coil within super coil -chromatin fiber -nucleosome
kiwi bird
-feathers superficially resemble mammal fur. -can't fly -nocturnal -forage for earthworms.
Pakicetus description.
-involucrum -eyes on top of head -pointed snout -wolf-sized mammal -slender legs
Dorudon (lecture)
-nasal opening has moved back. -40 mya
Eukaryotic cell characteristics
-nucleus -DNA within -organized linear chromosomes -No plasmids -Control gene expression with regulatory elements. -Introns and exons. -Mobile genetic elements.
Molecules genetics
-proteins -DNA -RNA -Water
Giant Beaver
-size of a bear -hung around lakes, marshes etc. -herbivore 18,000 yearsago
Basilosaurus
-size of school bus. -small, fully formed hind-legs Lived during Dorudon's time.
How can fossilization fail?
-skeleton trampled, sun-beaten, rain-soaked, nothing left to fossilize. -After formation; pressure, heat, erosion from wind/rain.
How Australopithecine more bipedal evidence than Ardipithecus ramidus?
-spines arched backwards, upper body sat above hips, no extending forwards. -legs straighter -knees located below midline of body -Feet; stout heel, beginnings of arches.
while a vestigial organ has lost its original obvious function, there might be
-subtle functions -adaptation might be repurposed (evolve) for another function.
Pakicetus
-terrestrial, mammal -carnivorous (teeth) -artiodactyl (even-toed ungulate) -greywolf-sized. more elongated. 52-48. -Eyes near top of skull (like croc), ambush predator. -Heavy bones "osteosclerotic bones" (walk along lake bed -involucrum
Corroborating evidence for past evolution by natural selection:
-vestigial traits and atavistic phenomena. -convergent (i.e. parallel) evolution (aka convergence). -fossils and the fossil record
How do evolutionary biologists find which species are closely related? (2 things)
1) Anatomical traits. 2) DNA.
How is evolution imperfect?
1) Can only modify what already exists. 2) Organisms acquire only so many beneficial mutations. 3) Beneficial mutations may have trade-offs.
Steps of encoding proteins
1) DNA 2a) RNA (primary) 2b) RNA (mature) 3) protein
What makes dolphins/whales different? (7 things)
1) Fish-like bodies. 2) Sculpted sleek curves (tuna/sharks) for aerodynamics. 3) Tails narrow down to small neck and expand to flattened flukes which lift to generate thrust (sharks similar but move side to side). 4) Blowholes/lungs, no gills. 5) Tiny "hip" bones (land vertebrates). 6) Long muscles length of bodies, not simple sets of muscles forming vertical blocks. 7) Live young, produce milk, mammary glands.
3 things beneficial mutations do.
1) Helps fight disease. 2) Helps thrive in environment. 3) Improves ability to mate.
3 Fundamental Principles for Evolution
1) Organisms inherit traits from ancestors, DNA. 2) Cells use DNA to build bio molecules, replicated and passed to offspring. 3) DNA not replicated perfectly, errors= mutations.
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.
Steps to make proteins from DNA.
1) Unwind protein coding gene. 2) Proteins converge at end called promoter region. 3) Then race to other side assembling new string RNA TRANSCRIPTION. 4) RNA TRANSLATION in ribosome. 5) Corresponding amino acids attach to nucleotides. 6) then attaches to growing protein.
two things evolutionists investigate.
1) adaptations 2) short-comings of adaptations.
3 actions of proteins.
1) enzymes; break down molecules in food we eat. 2) store important molecules; hemoglobin. 3) transmit info within or between cells.
Evolution of feathers First 3
1) hollow cylinder; origin of follicle collar. 2) Tuft of unbranched barbs to calmus; differentiation of follicle colloar. 3) Planar feather with unbranched barbs fused to a central rachis; barbs and barbules at base to calamus.
Mutations influenced by what two things?
1) other genes that enhance or suppress. 2) Environment favorability/in-favorability.
Teeth variations of modern cetaceans.
1) peg/cone like. 2) filter (baleen). 3) No teeth.
Steps of Replication of a DNA
1) unwind DNA 2a) Transcribe exposed DNA into primary mRNA transcript which is then modified into mature mRNA (introns removed). 3) Translate mRNA into protein. (introns already removed).
How many generations between Pakicetus and Blue Whale?
1,435,484 generations. 0.00379mm increase in cranium size per generation, smaller than human hair.
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)
Following are three more examples of pseudogenes and how they help us understand evolutionary history.
1. inactivation of a gene involved in vision 2. inactivation of a gene involved in Vitamin C synthesis 3. inactivation of genes involved in digesting insects
ive reasons why this fossil is a snake and not a legless lizard (there actually are extant legless lizards).
1. the body is extremely elongate relative to the tail. 2. the skull has the hallmarks of a snake (e.g. detachable jaws). 3. each vertebra has two articulation points (double articulation). 4. single wide scales (ventral scales) traverse the belly. 5. its diet consisted of vertebrates, swallowed whole.Note: snakes lack eyelids and external ear openings too- but these do not fossilize.
Protein coding genes make up what percentage of the human genome?
1.2%
uncoiled a single piece of DNA is how long?
1.8 meters is about 5.9 feet. -(0.09 mm) or 90 microns
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
marbled lungfish (Protopterus aethiopicus) has an enormous genome:
133 billionDNA base pairs human genome only has about 3.09 billion DNA base pairs.
How many pseudogenes in humans?
14,600
Archaeopteryx
145 mya) -a bird-like dinosaur. It had teeth and external grasping claws on all four limbs but only three fingers on each forelimb (hand) -long tail w/ vertebrae.
6th/last edition of on the origin of species printed when?
1869
Lake Michigan stromatolites dated...
2.2 billion years ago.
Nucleotides break down into how many different amino acids?
20
how many functional protein coding genes?
20,412
Adelobasileus
225 million year old fossil "mammaliaform", a little shrew-like creature. It was probably nocturnal to avoid the dominant dinosaur predators. It probably laid eggs and ate things like seeds and insects.
Ribosome reads RNA how many nucleotides at a time?
3
Trisomy
3 copies of a chromosome
age of stromatolites
3.45 billion years
How many nucleotide bases in human genome?
3.5 billion
Pakicetus and modern blue whale head size comparison.
35cm and 5.8m (580cm) -545 cm in 44.5 million years
compared to the X chromosome, your Y chromosome has only about
37% of the base pairs and 8% of the protein-coding genes but 44% of the pseudogenes (old defunct genes). That's a lot of pseudogenes for such a small chromosome.
Ardipithecus ramidus
A later pre-australopithecine species from the late Miocene to the early Pliocene; shows evidence of both bipedalism (anchors for muscles on pelvis shared by humans but not other apes) and arboreal activity but no indication of the primitive perihoning complex. -four short toes, kept stiff, great toes still opposable. -moved less fluidly than chimps.
Orrorin tugenensis
A pre-australopithecine species found in East Africa that displayed some of the earliest evidence of bipedalism. (after Sahelanthropus tchadensis) -Femur with head, to support upright torso, like human.
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
Insertion mutation
A segment of DNA is inserted into the middle of an existing sequence. may be 1 nucleotide or 1000 that are inserted. (possibly entire genes)
point mutation
A single base changes from one nucleotide to another (substitution)
Plasmid
A small ring of DNA that carries accessory genes separate from those of the bacterial chromosome -Genetic parasite; similar to virus. SOMETIMES beneficial, helps with abx resistance for example.
Oort Cloud
A spherical region of (billions of comets) that surrounds the solar system
Homo heidelbergensis
A transitional species between Homo erectus and Homo sapiens. Thought to be ancestral to both Neanderthals and modern humans. -higher skull, jaw that no longer projected as much as homo erectus.
Phylogeny (Cladogram)
A tree showing evolutionary relationships. Close branches mean close evolutionary relationships
Aneuploidy
Abnormal number of chromosomes. (duplicated or lost)
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
4 bases of a nucleotide
Adenine and Thymine Guanine and Cytosine
DNA bases
Adenine, Thymine, Guanine, Cytosine
RNA bases
Adenine, Uracil, Cytosine, Guanine
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.
Secondary loss (or reduction) of a structure can be seen as a kind of tinkering too. Such as;
All the apes have a coccyx. All apes lack an external tail. (vestigial)
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.
Heterozygous
An organism that has two different alleles for a trait
Homozygous
An organism that has two identical alleles for a trait
Phenotype
An organism's physical appearance, or visible traits.
What is a theory?
An overarching set of mechanisms or principles that explain a major aspect of the natural world.
Analogy vs. Homology
Analogy (non-inherited) Homology (inherited)
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.
Human Classification
Animalia, Chordata, Mammalia, Primates, Hominidae, Homo, Sapiens
Divergence
Divergent evolution is a type of macroevolution that creates more diversity in species in the biosphere. (five finger bones in several species).
How did Darwin gain credibility with his peers?
Documented monograph of barnacles.
How do scientists distinguish between two sources of carbon?
Due to biology's preference for lighter carbon isotopes.
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.
Why did bipedalism evolve?
Environment change from dense forests to more open woodlands.
Basilosaurus isis
Eocene (40-34 ma) Egypt, Pakistan, USA. -semi-aquatic -tiny hind legs. externalized. likely not functional. -coastal shoreline habitats -ambush predator, teeth.
Only one group of organisms living today produce methane...
Euryarchaeota, descendent of archaea. live in cows GI tract.
Snakes are another example of evolution as tinkering- and more secondary loss.
Evolved from an elongate lizard.
another example of a point mutation.
FOXP2 gene; if you have two copies you can speak normally.
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.
The earliest known placental mammal.
Juramaia is dated at 160 million years old. It was another little shrew-like creature. But this one gave live birth. It was probably also nocturnal and needed excellent hearing and olfaction.
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.
How do whales maintain ear canals?
Lamina; about one foot clump of wax
when do we first see enamel in the fossil record?
Psarolepis romeri, a bony fish from the Early Devonian period (about 400 Ma), combines enamel-covered dermal odontodes on scales and skull bones with teeth of naked dentine".. Had teeth but NO enamel on teeth.
largest creature that ever flew was called
Quetzalcoatlus northropi with a wingspan of about 36 feet.
Phylogeny of frogs
Ray finned fish> coelacanth> lungfish> tetrapods (frogs)
How did Nicholas Steno come to his conclusion?
Recognized triangular rocks found on mountains known as "tongue stones" were actually shark teeth.
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
Enamel started where in fossil record?
Scales of fish and later on teeth.
Difference between seals/ sea lions.
Seals; hindleg> propulsion also has claws similar to terrestrial animal. Sea Lion; forelimb> propulsion no claws/nails on flipper digits hidden in flippers.
Deletion mutation
Segment of DNA may be deleted accidentally, small portion of gene may disappear, or entire set may be removed.
By end of Eocene.
Semiaquatic species extinct. Fully aquatic species evolved and became top predators of the ocean.
Possible function for vestigial pelvic bones in cetaceans
Sexual, attached ligaments anchoring penis/clitoris.
Differences between elephant ancestors found in Siberia and modern African elephants? (Gerorges Cuvier)
Shapes of teeth.
Pakicetus habitat
Shoreline; comfortable both in and out of the water; perhaps it was an ambush predator, like a crocodile. Notice how the eyes are oriented toward the top of the skull.
Ambulocetus movement
Short legs, large feet. Swam like otter, kicking feet and bending tail.
Humans commonalities with fish.
Similar arches develop near head during embryonic development, fish (gills) human (jaw bone). Humans also develop blood vessels similar to fish gills but are then modified.
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.
Compsognathid with simple feathers.
Sinosauropteryx)
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
Difference between tetrapod and teleosts fins
Tetrapod (lobe fin) Teleosts (Fin ray)
There is an official name for hippopotamus + cetaceans (whales) clade.
Whippomorpha.
Gene family? What does that mean?
a "family" of genes are related to each other. They are a monophyletic group! They have a common ancestor. They are a lineage of genes that has evolved by repeated gene duplication!
Adaptation
a change or the process of change by which an organism or species becomes better suited to its environment.
Bonobos (Pan paniscus) have
a coccyx like us. Bonobos are old world apes. There is no external tail.
Plants and animals have eggs and sperms, but there is no such thing as
a female (or male) fungus.
Archetype
a fundamental plan to which some variations could be added. (believed by early evolutionists.)
Clade
a group that shares a common ancestor (monophyletic group). Clades often nest within other clades.
ungulate
a hoofed animal
And the grey langur (old world monkey) has
a long tail.
meterorite
a meteoroid that does not completely burn up in the atmosphere and strikes the surface of a moon or planet
FOXP2 gene evidence for human evolution.
a point mutation is all it takes to change the human version back into the chimp version, then this suggests that the human version evolved by a simple mutation and played an important role in the origin of human speech.
The simplest possible DNA mutation is called a
a point mutation- a change (substitution) of just one nucleotide for another.
Premineralization
a process of fossilization which deposits from internal casts of organisms. *can happen in tissues like wood, bone, and shell...
duplication mutation
a segment of DNA is copied multiple times
The Alu transposon "jump" interrupted a gene called TBXT, resulting in
a shorter (truncated) TBXT protein. (why apes don't have tails) also neural tube defects if truncated.
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)
genome duplication
addition of a complete set of chromosomes ENTIRE genome duplicated
The human genome
all genetic info in a human cell.
the upper and lowercase letters refer to
alleles (different forms) of the same gene.
What did Buffon propose about early life?
already divided into distinct types, an "internal mould". But that life could also be transformed over time in a new environment.
Proteins are chains of building blocks called....
amino acids
Superclass: Tetrapoda:
amphibians, reptiles, birds, and mammals (i.e. all the chordates
compared to more distant (earlier) common ancestors, many primate lineages (including apes) became more visual (e.g. dependent on daytime color vision to find food)...and less dependent on
an acute sense of smell. Therefore, partial secondary loss of olfactory was not such a big deal.
Chitinase
an enzyme that chops chitin into smaller bits for digestion.
Clade
an organism and all of its descendants
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
plesiomorphy
ancestral character state
Astralagus
ankle joint, "double-pulley" shape in whales. "single pulley in horses and humans"
a biological taxon is
any group at any level in a classification hierarchy (e.g. population, subspecies, species, genus, family, order, etc.)
phylogenetic trees are based on
apomorphies.
A derived character state is called an
apomorphy
a derived character state is an
apomorphy; seen in only one species (or exemplar
example of human vestigial structure (from lecture)
appendix (caecum)
Acanthostega
aquatic tetrapod with legs; suggests legs evolved in organisms that still lived under water. Could not hold own weight on land.
Evidence that architecture of eukaryotes was;
archaeon
Convergent evolution
arriving at the same solution from different starting places.
cetaceans most closely related to....
artiodactyls; (hippos, most closely related).
asexual organisms
asexual fungi, asexual plants, asexual snails, asexual insects, etc. rare cases of asexual vertebrates such as fish, snakes, lizards,
What connects Indohyus and Pakicetus to the artiodactyls?
astragalus
How do we know that cetaceans most closely related to artiodactyls?
astralagus, ankle bone with distinctive double pulley shape.
Flight feathers have
asymmetry
8 pseudogenes are interpreted as
autapomorphiclosses in the Denisovan lineage...* loss of function
10 pseudogenes are interpreted as
autapomorphiclosses in the Neanderthal lineage (compared to us),
a unique apomorphy—is called an
autapomorphy
There are 22 pairs of
autosomes and one pair of sex chromosomes.
Jean-Baptiste Lamarck argued
complex species evolved from simple ones. in a "ladder" of progress
Obsidian Blades
crafted by hominins 270,000 y/a.
Straw Man Argument
create false target and attack it, distracts from real issue,
plural= data; singular =
datum
Pseudogenes are
deactivated or defunct genes. But the DNA sequence of the gene often persists unused (genetic fossil).
vestigial
degenerate, rudimentary, or atrophied, having become functionless in the course of evolution.
apomorphy
derived character state
Most compsognathid dinosaurs
did not have feathers. -Compsognathus (About the size of a chicken)
Dinosaurs lived in arctic circle;
did not migrate; were able to warm own blood.
a phylogeny is conceptually similar to a genealogy.
difference is that the genealogy deals with relationships among individuals. The phylogeny deals with relationships among lineages that are each represented by an exemplar
Extant birds are...
dinosaurs
23 pairs of chromosomes in the normal human
diploid cell.
why mammals from synapsids?
diverse dentition (reptiles don't)
Odontocetes
dolphins; evolved muscles/organs to produce high-pitched sounds in nasal passages leading to blowholes. Listening to echoes for hunting/communication. Heightened intelligence. Live in large groups with complex socialization. Swim after prey.
Synapsids
dominant, sprawling, reptile-like vertebrates before animals even resembled mammals. Early ancestors of mammals
Proteins make up most of body's
dry weight
Mummification can result from any conditions that prevent decay
e.g. freezing cold, acidity, or dehydration.
original cells show only one pair of chromosomes (one from the "mother" and one from the "father").in a human cell there are 23 chromosomes; Therefore....
each of the 22 autosomes can recombine!
microbatapomorphicabout 1200 sp
echolocation nocturnal
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
Exons
encode amino acid sequences (protein) but introns do not.
free living bacteria evolved by;
endosymbiosis into organelles (mitochondria and chloroplasts) closest living relatives.
Adaptation can be both...
endpoint or process leading to endpoint
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)
Evolution as Tinkering example;
evolution of hearing in mammals. -same set of tiny bones is found in all extant mammals. -"baleen" in pterosaur. -Lamellae in flamingo & duck.
n Chromosome 2 (human) the corresponding ape genes are
exactly homologous and we can still see the smoking gun for this fusion i.e. remnants of the extra telomeres and centromeres can still be found just as one would expect.
an adaptation repurposed (evolve) for another function is called a ......
exaptation
coccyx does have an important function, especially in humans. This is probably an
exaptation involved in running. More about human running later. Muscles that attach to the posterior (dorsal) coccyx "include the gluteus maximus, which is the largest of the gluteal (buttock) muscles and which functions to extend the thigh during ambulation."
each taxon* included in a phylogenetic tree is an
exemplar
uniqueness is all due to mere reshuffling of
existingvariation
segments that stay in RNA transcript;
exons
house sparrows are what?
extant theropods (dinosaurs)
Latimeria
extantprimitive lobe-finned fish. It is a large animal, growing up to 1.8 meters in length! Individuals are long-lived and occur in deep submarine canyons and caves. Note that robust bones occur in the limb-like "lobes" of the fins. Coelacanth
Merychippus intermontanus.
extinct three-toed horse. -may have helped in marshy habitat.
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)
Which came first feather or flight?
feather
Trait linking birds and theropods
feathers. Had strange outgrowths; vanes, barbs, and central stalk, traits only found in feathers.
William Smith
first geological map, discovered layers of rock contained distinctive fossil sets. Went to debtors prison r/t bad luck.
Omuamua
first recorded interstellar object (from another solar system) Over 4 lightyears away. second one (Borisov) seen in 2019, NOT same one.
inversion mutation
flipped around and inserted backwards into original position.
What do amino acids do?
fold into complex structures and then join with other proteins to carry out sophisticated functions.
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.
Pseudogenes
former genes that have accumulated mutations and are nonfunctional
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.
Archaeoptyerx
fossilized first bird; feathers, teeth in beak, claws on wings, and long reptilians tail.
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.
An important thing to remember about cladograms is that branches can be
freely rotated at any node. For example, these two trees are equivalent; they tell the same story.
Purpose of caecum (appendix)
from the days when our ancestors ate more green vegetation and less meat. fermentation chamber. -now possibly harbors beneficial bacteria. (homologous trait)
Eukarya
fusion of bacteria and archaea >LUCA predates that
human Chromosome 2 evolved via
fusion of two smaller chromosomes
Note that olfactory receptor genes (ORs) are a
gene family
proteins encoded in....
genes
genetic drift
genes/traits more common by chance.
Biological evolution is defined as:
genetic change in a population of organisms.
Genotype
genetic makeup of an organism
meiosis produces
genetic variation by reshufflingexisting variation (recombination).
To understand biological evolution by natural selection, it is important to understand
genetic variation.
Before rise of teleosts, oceans top predators were....
giant sea scorpions. 6 feet long.
megabat pleisiomorphicabout 200 sp.
good vision and olfactory- active day or night
Why do kiwi birds have feathers?
insulation. They live in cool, shady forest environments in New Zealand
information proteins
insulin; signals muscle cells to pick up glucose.
Francis Galton
interested in link between heredity and height
With cladistics a layperson can;
interpret data and not take an authorative figure's word for it
segments removed from RNA transcript;
introns
Describe Darwin
introverted, sensitive, against slavery, mother died when he was eight, he was 1 of 6 children, daughter died when she was 10. Grew up wealthy, hard working, declined medicine almost clergy but went on exhibition at 22. 5 years later back and married Emma, had 10 children.
Trait linking Pakicetus to modern cetaceans?
involucrum
Fungi do not have eggs and sperm
isomorphic gametes look the same
is a platypus primitive or derived?
it's both. The platypus exhibits some primitive (ancestral) traits but also derived traits.
Why to evolutionists reject creationism?
its objections to evolution have no basis in evidence and it is a non-scientific view of nature.
A node is any place on a tree where branches
join.
Methionine (Met) is encoded by
just one codon: AUG (which is also the START codon). -Others are encoded by two to six codons.
There are 853
known olfactory receptor genes (ORs) in living humans. Of these, 55% have lost their function i.e. they have become pseudogenes (usually because of mutations resulting in stop codons).
Cassowaries
large omnivorous birds, large dagger-like toenails that can gut adult humans.
Evolution happens when
mutations become more or less common over generations.
abiogenesis (spontaneous generation)
natural process, life originates from inorganic (nonliving) matter.
Nonrandom spread of beneficial genes....
natural selection
where are vestigial pelvises in modern whales?
no longer attached to the rest of the skeleton (bone to bone)! They are suspended in a matrix of soft tissues.
In parthenogenetic species there are usually no
no males, only females (if the species has gender at all).
like most small mammals in the modern world, early mammals (our ancestors) were likely
nocturnal. They would have needed an excellent sense of smell—olfaction—to navigate and survive in the dark.
Birds ARE
non-avian dinosaurs
one chitinase gene remains functional in humans
not expressed in the GI tract but LUNGS possible antifungal properties.
extant =
not extinct
the splint bones in horses do still have a function,
not for bearing weight, (sometimes they are missing altogether), they can fuse to the cannon bone and share the function of "anchoring fascia and other tendon/ligamentous attachments to the limb". NEW function!
Early (larval) stage in Australian lungfish development...
notice how the radius and ulna are separate in the larva.
The term "character" means any
observable trait or characteristic that can occur in two or more states. These states are called character states.
Two species of cetaceans today
odontocetes and mysticetes >split from common ancestor 40 million years ago.
Select any extant species of modern ray-finned fish as an exemplar, and it will exhibit one or more
old (ancestral) traits that place it in this ancient lineage, but it will also tend to exhibit new (derived) traits that evolved more recently.
Wattieza
oldest tree-like plant. 385 million y/o. Stood 8 meters tall.
over evolutionary time, chimpanzees have lost function of fewer
olfactory genes, compared to humans... -chimps have a superior sense of smell.
In bird diagram in book....
only darker birds able to reproduce successfully.
Endosymobiosis
organelles were once free-living bacteria that were incorporated into a larger eukaryotic cell
Ratites
ostrich, kiwi, emu, cassowary; flightless birds
What percentage of your genome consists of these little parasitic robots (mobile genetic elements/ transposons)?
over half! Together with Non-functional relics.
Age of cyanobacteria close to oldest evidence of ;
oxygen in fossil record (produced O2 during photosynth)
Anticodon
pairs with a codon on the mRNA.
Steno's realizations made way for what field of study?
paleontaology
Archaea are not
photosynthesizes
note: many are heritable and so transposons can also provide
phylogenetic information.
A phylogenetic tree is also known as a.
phylogeny
Stop codon mutations resulting in pseudogenes can be helpful in being evidence for .....
phylogeny
Lipid biomarkers extracted from organically preserved Ediacaran macrofossils unambiguously clarify their
phylogeny. Dickinsonia and its relatives solely produced cholesteroids, a hallmark of animals.
Hollow space in hairs;
place to trap heat
Syncytins are involved in the formation of the syncytiotrophoblast in the
placenta
Evolution of lignin and other tough plant compounds allowed what?
plant lineages to grow; stems, stalks, and trunks.
An ancestral character state is called a
plesiomorphy
muscle growth in whippet pups is related to
point mutations
Why was the Tiktaalik study site dangerous?
polar bears
How is a theory expressed as a fraction?
power of theory = How much it explains. ------------------------------ How much it needs to assume.
Rodhocetus
preceded Dorudon. - vestigial pelvis -astralagus -short limbs like SEAL.
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)
Macropoma
presumed extinct for over 65 million years. Coelacanth
An outgroup is a taxon known or suspected to be
primitive (ancestral).
Climactichnites
probable trackways from slug-like animal
Bacteria and Archaea are both
prokaryotic; cells lack a nucleus. dna is one big loop, not contained
proto-humerus in Tiktaalik allowed
proto-humerus in Tiktaalik allowed it to lift its head and shoulders above the surface on and near the shore...
A mutation that causes a premature STOP codon results in a
pseudogene
another - convergent* - evolution of flight in reptiles...
pterosaurs (Pterosauria).
Mutations are.....
random
Translation
reads RNA nucleotides in 3s and builds the corresponding amino acid chain (early protein)
What would theropods have used feathers for?
recognizing each other, attracting mates. could NOT fly. Flight stroke, waving feathers to help get prey (pre-flight). had color generating melanosomes. Maybe used to shelter eggs.
Meiosis results in
recombinantsex cells (gametes) such as sperm and eggs.
Argument of what good is half an eye is example of....
red herring
During mitosis, chromosomes are
replicated (duplicated) into identical chromosomes. -usually no genetic variation produced.
After volcanic ash
resets radiocarbon clock to zero.
nondisjunction
resulting in gametes with too many (or too few) chromosomes.
Atavism
reversal to former state
Radiometric dating starts when....
rock cools and becomes solid.
Age of Earth
rounded off to 4.5 billion years.
Rodhecetus movement
seal-like limbs, likely only able to drag self around on land.
Chromosomal crossover at synapsis;
sections of the chromatids are exchanged...
542.68 ± 1.25 Ma (terminal Ediacaran)
sediment bulldozers... i.e. actively moving around.i.e. not passive filter-feeders or passively photosynthetic.
genetic code
set of rules governing the nucleotide triplets into specific amino acids.
Not all eukaryotes have
sex chromosomes
not all eukaryotes are
sexual
meiosisis different. Meiosis happens during
sexual reproduction.
synapomorphy
shared derived character state
Chengjiang fossil deposit
similar fossil in china to burgess shale
homology
similarity acquired by inheritance from a common ancestor.
Homology
similarity resulting from common ancestry Ex: arm bones of humans, seals, and bats.
principle of parsimony
simple answer = better answer
Platyhelminthes
simple eyes
An exemplar is a
single example or representative of an entire lineage.
each homolog is a
single linear molecule of double-stranded DNA.
note: the functional form of the interphotoreceptor retinoid binding protein geneis
single-copy and essential for vision.
manatee ancestor
sirenian
Onychonycteris
skull suggests that this bat lacked adaptations for echolocation. And unlike any extant bat, all five fingers showed external claws.
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.
microRNA
small single stranded RNA molecules that bind to mRNA and can degrade mRNA or block its translation. (Can regulate expression of genes)
hominim walking on shore note;
some fossils are mineralized (petrified) but others are not.
not all transposons are "junk" and not all transposons are parasitic robots.
some transposons have been co-opted during evolutionary history by the host for useful purposes. One example is the "syncytin" gene which apparently enabled the evolution of placental mammals!
Taxonimist
someone who studies the relationships between organisms and classifies them
Over time populations become so different that they become separate _____.
species
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.
Quantitative Trait Loci (QTL)
stretches of DNA that either contain or are linked to genes influencing a trait such as behavior
similarities in parallel evolution are;
superficial
zircons are actually older than the oldest known intact
surface crustal rock formations on Earth. Zircons (4.4 bya) oldest known rocks (4 bya)
7 pseudogenes are interpreted as
synapomorphiclosses in the Neanderthal lineage and modern humans (us),
99 pseudogenes are interpreted as
synapomorphiclosses* shared by humans and chimpanzees...
blowhole and complete loss of external hindlimbs are
synapomorphies in extant whales.
A shared derived character state is called a
synapomorphy
We would say that the double-pulley astragalus is a
synapomorphy that helps to define the Artiodactyla .
The presence of an involucrum is a
synapomorphy that unites and helps define the whale clade (Cetaceans).
Mammals are descended from sprawling, reptile-like vertebrates called
synapsids that first emerged 320 million years ago.
astralagus in human
talus
branches of phylogenetic tree
taxons
In the modern world ungulates are vegetarian but 52-48 ma (million years ago) there were also carnivorous ungulates. Why do we think it was carnivorous?
teeth
Transfer from teeth to baleen in whales.
teeth> baleen & teeth> baleen
Cladograms can take various shapes, it just depends on the style of cladogram that you prefer. Each of these
tells exactly the same evolutionary story.
Atavism (lecture)
tendency to revert to ancestral type or condition. (dolphin sprouting tiny projections "hindlimbs")
describe turtle evolution
terrestrial ancestor, homologous arm/finger bones within flippers. OLDER than crocs. Descend from diving lizard.
frogs (remember) and salamanders; salamanders are the earliest lineage of extant
tetrapods. In a very real sense, we are all modified salamanders (wink)
Meiosis 1
the chromosomes are duplicated, pair up, and interact in a process called synapsis.
Sahelanthropus
the first known bipedal hominin. 7mya
Genotype:
the genetic makeup of an organism; usually contrasted with the phenotype (genotype: the genetic recipe* for the phenotype).
Cell division in eukaryotes is a lot more complicated...
the genome in each cell consists of one or more linear. DNA molecules that are organized into chromosomes(seen here condensed during metaphase).
Quetzalcoatlus
the largest of many species in a spectacular adaptive radiation called the Azhdarchid lineage, long extinct. -estimated to be 3 m (9.8 ft) high at the shoulder -radius are partially fused (36ft wingspan) -could also walk around on all fours.
aneuploidy,
the loss or gain of individualchromosomes due to nondisjunction during meiosis.
Phenotype:
the manifestation of a genotype (body, development, functions, behaviors, etc.)
monophyletic
the members of each domain traces back to a single common ancestor (long extinct).
once a gene is duplicated, one copy is preserved with its original DNA sequence and function... but the other
the other copy is not needed for that function anymore and so it is free to evolve via mutation and then natural selection and achieve a new function.
Ganoine
the same type of skin enamel we see in the extant gar (alligator gar). Sharp scales.
There are three codons that encode termination of
the translation i.e. STOP codons.
to ambush invertebrate prey on the shoreline would have been a new niche (ecological opportunity). Note: why invertebrate prey only?
there were no land vertebrates yet.
Liaoconodon hui
therian mammal with ear bones still attached to jaw.
describe Cassowaries
theropods, has casque to cool temperature. dangerous tallons
In snakes
thoracic vertebrae extend from the head all the way to the cloaca i.e. urogenital opening. Incidentally, we also see a cloaca in birds. This makes sense; they are reptiles after all.
How are mammalian ears unique?
three middle ear bones, lacking in reptiles and birds, used to help ancestors bite.
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.
Echolocation is an autapomorphy seen in the
toothed whale exemplar.
which whales use echolocation?
toothed whales NOT baleen whales.
monophyetic group
traced back to common ancestor
To produce a protein, eukaryotes do what?
transcribe a gene in the form of an RNA molecule. During transcription, edit out noncoding segments of the gene.
Tiktaalik
transitional fossil that linked ancestral fish with later tetrapods. (375 mya Devonian period) in Canada
Madagascar became an isolated island about 88 million years ago, before the evolution of
true cats. inhabited by ancient members of the mongoose family similar to Galidia elegans which you can still find there. There were apparently no large predators back then, just little dainty ones.
chromosome fusion mutation
two chromosomes are joined together as one
Apparently, tetrapods (amphibians, reptiles, birds, and mammals) evolved from a common ancestor that was a
type of ancient, long-extinct fish.
Eukaryans can be
unicellular or multicellular.
Bacteria and archaeans are
unicellular.
autapomorphy
unique derived character state
A phylogenetic network is
unrooted
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
What do scientists do?
use evidence to construct testable explanations about natural phenomena. The Seek to Understand the Invisible.
Phylogenetics
use of genetics to phylogenetic pattern
Exchanges made during synapsis will
vary from gamete to gamete. no two gametes will ever be exactly the same (even within the same ovary or drop of sperm).
Tetrapods
vertebrate animals having four feet, legs or leglike appendages
scalePhylogenetics and the molecular clock* tell us that the visual megabats and nocturnal echolocating microbats diverged
very early soon after the K-T boundary 66 mya. (after mass extinction of dinosaurs)
Mandrills (Mandrillus sphinx) have
very short tails...Mandrills are old world monkeys.
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.
vestigial structures in horse
vestigial fingers (or toes) leaves after fetal development. "splint bones".
Remember, the humerus is seen in all* tetrapods.
vestigial or secondarily lost in some lineages of course e.g. snakes, legless lizards, worm-like amphibians called caecilians, etc.
sensory organ found in baleen whales and hippos
vibrassae
If we descend from archaea then we really are;
walking consortia of prokaryotic cells that evolved.
in chimpanzees (also gorillas and orangutans), there are 23 autosomes but two of the small ones are now called 2a and 2b because
we now know that they fused in the common ancestor of humans.
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
Ichthyosaurs
were aquatic dinosaurs. Fossils show us that they had dorsal fins and tails, as do fish, even though their closest relatives were terrestrial reptiles that had neither dorsal fins nor aquatic tails.
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
marabou stork (Leptoptilos crumenifer)
with flexible, hair-like "feathers" on the head and neck. This bird often scavenges on the bodies of large animals alongside vultures. sparse, flexible, hair-like "feathers" mixed with fuzzy down. also note the short, dark whisker-like "hairs".
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.
Examples of odd-toed ungulates (Perissodactyla)
zebra, rhino, tapir
What did early synapsids look like?
Dimetrodon; sail-shaped back. Others looked like turtles with fangs. The way skulls fit together only found in mammals.
Is evolution entirely random?
No
Are amino acids only from biologic sources?
No many chemical reactions produce them.
all-female (parthenogenetic) Mourning Gecko Lepidodactylus lugubris.
No one has ever found a male. In captivity, a lone female will lay eggs that hatch into more females.
Is evolution entirely random?
No only partially
are tarpit fossils mineralized?
No petroleum covered. REAL bones.
Is a platypus' form considered primitive?
No, has own unique features as well as primitive ones.
Can amino acids be made into proteins without biology?
No, needs enzymes produced by organisms.
Do individuals evolve?
No, populations do
Do all horses have splint bones?
No, variable
hypothetical ancestor for bats
Nocturnal, Arboreal. Developed hearing, elongated digits with webbing, potential patagium. Ultrasonic calls for communication.
Describe human evolution
Not from single lineage to current form. perhaps 20 species of bipedal apes with different adaptations.
How does the history of life unfold?
Not in a line but encoded in billions of branches.
extant Queensland lungfish Neoceratodus forsteri
Note the lobed fins. These are actually used to push through mud and when excavating burrows.
homologous morphology
Now we have DNA sequence data and other kinds of molecular data.
The principle of parsimony is also known as
Occam's Razor.
Presence of purple sulfur bacteria means what?
Oceans likely toxic to us anyways at time. Found only in extreme, low oxygen, high sulfur environments.
Describe Carl Linnaeus
Odd, possibly murdered partner to receive full credit for classification system.
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).
Darwin argued what about natural selection?
Over vast time, simple things> more complex.
What is a hypothesis for a mass extinction 252 million years ago?
Oxygen loss in oceans beginning in depths then spreading to shores. Corroborated by fossil record starting in depths. (Permian-Triassic Extinction)
What did Philip Gingrich find?
Pakicetus, organism similar to dorudon especially in teeth.
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).
convergent evolution
Parallel Evolution toward similar characteristics in unrelated species (bird and bat wings)
Earliest signs of life likely from what?
Photosynthetic bacteria; producing carbon isotopes.
how do phylogenetic unity of life and natural selection fit together in Darwin's idea?
Phylogenetic unity (descent) Natural selection (with modification) *ALSO genetic drift
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.
Planarian
A free-living flatworm found in unpolluted ponds and streams. (KInni) Simple eyes. Scavengers.
Indohyus
4 legged terrestrial ancient relative of whales. House cat-sized. arteriodactly.
Average lifespan of a fossil taxon.
4 million years
Evolution of feathers; 4 and 5.
4) closed pennaceous vane; differentation of barbule plates. 5) Closed asymmetrical vane; Addition of mare ridges on one side.
The Late Heavy Bombardment happened how long ago?
4.1 to 3.8 billion years ago.
Peregocetus pacificus
42.6 mya transitional waking whale. about 10 feet from nose tip to tail tip (proto fluke of tail similar to modern whales)
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)
Humans have how many chromosomes?
46
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.
The Alu transposon has
50,000 active copies.
Oldest evidence of animals that can move.
585 million y/o tracks in fossil by small worm-like organisms.
Of the 64 possible codons
61 represent amino acids, and three are stop signals.
Burgess Shale number of species found?
93+ species -died 505 mya -largest species discovered recently. -Bank collapsed> flung into )2 free abyss.
Are there any transitional fossils? Answer: yes.
95 million year old fossil snake Eupodophis descouensiis one of just a few snake fossils (so far) that show vestigial limbs. -Pachyrhachis problematicus lived between 93.5-99.6 mya
oldest homo sapien fossil
<200,000 years old, found in Ethiopia.
Dorudon dissimilarities to modern cetaceans.
>Blowhole midway up snout. >Complete hind legs (very small). > incisors and front molars, complex structure (like land mammal), NOT like modern cetaceans.
Dorudon similarities to modern cetaceans.
>Completely aquatic. >involucrum
What things did Jean-Baptiste Lamarck propose?
>Humans/large species descended from microbes. >Giraffe stretched neck and "nervous fluid" caused it to lengthen. And that would pass to offspring. >Did not accept extinction.
Fossil records suggest natural selection favored what?
>Short legs, for swimming. >Nostrils shifted up, eliminating need for gills, air taken in more efficiently at water surface.
What puts whales at risk now?
>Small population size. WHY? Disease Pollution Heavy Fishing Genetic disorders (inbreeding).
Corroborating evidence for natural selection>evolution? (7 things)
>Vestigial traits >Atavistic phenomena >convergent (parallel) evolution/ convergence. >Fossils/Fossil record >Phylogenetics >Frequent evolutionary constraints >Evolutionary anachronisms
scientific theories not likely altered.
>heliocentric theory >cell theory >plate tectonics theory.
phylogenetic tree
A branching diagram representing hypothesis about evolutionary history of group of organisms.
Polyploidy
A chromosomal alteration in which the organism possesses more than two complete chromosome sets.
scientific theory
A comprehensive explanation of nature supported by a vast body of evidence. Usually not likely altered.
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
Linnaean Classification System
Binomial nomenclature
The marsupial mole is blind
But the presence of the pseudogene* means that it likely evolved from an ancestor that had vision.
Earliest members of many living groups of animals first appeared during what?
Cambrian period.
Most useful thing about scientific method.
Can be used to make predictions about things not yet observed.
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.
Fitzroy
Captain of the HMS Beagle. bumpologist (phrenology) dining partner with Darwin heated debates over slavery.
large plant species began to appear in what period?
Carboniferous period. Ferns and gingko trees still exist today. Flowering plants then more favored.
Why did cetacean population soar 20 million years ago?
Diatoms algae> Eaten by prey creatures> Eaten by cetaceans.
Why was Fitzroy suspicious of Darwin?
Didn't like shape of his nose, he was a bumpologist (phrenology)
Who created the system for classifying species into different groups (taxonomy)?
Carl Linnaeus
Darwin possibly contracted what in jungle?
Chagas disease
First person to think about how whales evolved?
Charles Darwin
The Origin of Species written by.....
Charles Darwin
Water and proteins are responsible for....
Chemical reactions essential for life.
Monosomy
Chromosomal abnormality consisting of the absence of one chromosome from the normal diploid number
What did Buffon propose about Earth's creation?
Comet struck sun> Breaking off debris (Earth)> Earth cooled/hardened> Oceans and dry land formed> particles in oceans led to plants/animals creation> As earth cooled animals migrated to warm tropics.
Chondrites contain what
Contain chondrules; (round things in meteorite) believed building blocks of formation of chondrules, allows for dating.
Evolution's raw materials
DNA, chromosomes, sex, meiosis, genetic variation, individuals, and populations..
Central dogma of information flow
DNA-transcription-RNA-translation-protein
Darwin's explanation of cetacean evolution.....
Descended from mammals that lived on land, evolving to marine mammals through natural selection.
What is evolution?
Descent with modification; NON-RANDOM survival of randomly varying heredity units.
How did earth look 1.5 billion years ago?
Desolate; no trees, flowers, moss, no marine animals or coral. Just microbial life.
William Smith produced the first.......
Detailed geological map with strata where different fossils found.
Lynn Margulis
Developed the Endosymbiotic Theory. Punished by establishment; no one believed her. Mitochondria from non-mitochondria. The Origin of Mitosing Eukaryotic Cells
Oldest recognizable multicellular eukaryotes?
Filaments of algae, 1.6 billion y/o. Before that; unrecognizable disks.
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.
Your Inner Fish
Fish-human; written by Neil Shubin
cat-like predator in madagascar
Fossa; cat-like skull, teeth, and skeleton. It even has semi-retractable claws. NOT a cat, its a mongoose.
How did earliest cetaceans (Indohygus/Pakicetus) move?
Four legs, may have swam by kicking legs.
One out of every five calories is used to...
Fuel your brain.
One of the earliest evolutionary thinkers.
Georges Buffon; wrote an encyclopedia about natural world.
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.
Trans-humanism
How bodies are likely to change over time.
power of a theory fraction for evolution=
How much it explains: The diversity of life on Earth (including humans) and probably elsewhere in the universe. ________________________ How much in needs to assume: Non-random survival of randomly varying heredity units.
Example how evolution can make complex things more simple.
Human ancestors lost tails, only vestigial bones at base of spine.
Why did whale populations decrease in 1800s?
Human hunting; Whale oil (for lamps) and baleen (for corset stays). Close to extinction.
LUCA
Last Universal Common Ancestor. The shared ancestor that multiple organisms diverged from
What did William Smith discover?
Layers of rocks contain distinctive groups of fossils.
Nicholas Steno's Radical New Idea
Life and the planet that supported it had a history filled with change, and the earth itself kept a record of history.
Why does evolution not violate the second law of thermodynamics?
Life does not evolve in a closed system, sun is outside source of energy.
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?
Species that left footprints in preserved in volcanic ash?
Likely Australopithecus afarensis
Location of Pakicetus determines what?
Likely lived on land.
Consensus (embryological) for why cetaceans no longer have legs?
Limb buds die back after sprouting at the embryonic level, gene mutations stopping growth of limbs.
Explain belief of species hierarchy.
Medieval theologians envisioned "Great Chain of Being" low to high (Plants>Humans>Angels) Some used to justify slavery, poverty, species superiority, etc. >Darwin rejected this idea.
To understand genetic variation, it is important to understand
Meiosis and genetic recombination; relatively complicated processes. This is one of the reasons why biological evolution in populations is misunderstood and rejected by many people.
Plesiosaurs
Mesozoic marine reptiles with small heads, long necks, and flippers
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.
Mule vs. Hinny
Mule: Hinny:
What did James Hutton realize about earth?
Must be vastly old based on time of erosion, islands made from layers of sediment, etc. Regular cycles of destruction and rebuilding.
Example of evolutionary trade-off.
Mutation for increased number of offspring may decrease life-span. May be accompanied by disease causing genes. (cancer)
Are all fossils petrified?
NO
Are evolution and origin of life the same thing?
NO, evolution requires populations to evolve.
Natural selection is.......
NOT random
Homo floresiensis
Nicknamed "Hobbit" for its diminutive size, a possible new species of Homo found in Liang Bua Cave, on the Indonesian island of Flores. (cousins, not ancestors) lived 19,000 y/a.
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).
Sahelanthropus tchadensis
The earliest pre-australopithecine species found in central Africa with possible evidence of bipedalism. -smaller canine teeth than apes. -cheek teeth thicker. -foramen magnum downward, head atop neck, not extending forwards.
Puijila darwini
The most primitive representative of Pinnipedia, was otter like in appearance. Walked on land NOT in weasel family.
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
Bird skeletons share similarities with which group of dinosaurs?
Theropods; bipedal, meat-eating dinos. (T-rex, Velociraptor)
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
From fins to limbs: homology through time...
Tiktaalik forelimbs have bones that are interpreted as homologous with the humerus, radius, and ulna seen in tetrapods. Tiktaalik is classified as part of the Tetrapodomorpha, a clade that includes some lobe-finned fish and the true tetrapods (Tetrapoda).
Example of extant ray-finned fish with derived characteristics.
Tuna can generate heat to be warmer than water (derived)
classified groups of human ancestor groups.
Vertebrates (skull, brain, spine) Tetrapod (legs, toes, neck, gills lost) Amniotes (internal egg) Mammals (hair, milk)
Virtually all mammals have a functional gene and therefore synthesize their own;
Vitamin C. But a few bats, guinea pigs, and anthropoid primates have a pseudogene instead. The gene is there but deactivated. Incidentally, deactivations in these three clades were independent events.
Examples of evolution of behavior/language.
Walking upright, symbiotic relationships /Latin-Spanish
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.
Do mutations provide raw materials for innovations?
Yes
Bird bones homologous?
Yes but modified
Can wings become vestigial?
Yes flightless birds (emu, kiwi, etc).
Can vestigial leg/pelvic bones be asymmetrical/deformed?
Yes! exactly what we would expect in structures not maintained by natural (stabilizing) selection.
oldest known surviving solids on Earth
Zircons
Another use for coccyx
balance while sitting
baleen and tooth loss are autapomorphies in the
baleen whale exemplar.
Mysticetes
baleen whales, eventually lost teeth developed baleens to trap small animals for hunting.
Nucleotides
base, sugar (deoxyribose or ribose), phosphate.
Ambulocetus; Why do scientists think that it had webbed toes (and fingers)?
because the fingers and toes are long and slender (like a seal's).
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.
Tiktaalik characteristics
bottom dwellers; likely an ambush predator that could push off the bottom with its forelimbs. Lobed fins; homologous forelimb bones. Tetrapodomorpha
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.
Prokaryotic cell division is straightforward-
cells divide in a process called fission and normally there is absolutely no reshuffling of the gene order.
whales and dolphins are known collectively as...
cetaceans
Polypeptide
chain of amino acids
the astragalus can be viewed as a "character" with two states (shapes in this case).
character state 1: single-pulley character state 2: double-pulley
What does claudistic data consist of?
characters
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.
DNA coils (histones) further arranged into tightly bundled rods called...
chromosomes
The phylogenetic toolkit for making cladograms is called
cladistics
asexual, meaning that they reproduce by
cloning or parthenogenesis.
manatee
closer related to elephants. (vestigial pelvis) five finger nails despite phalanges not extending to surface.
Ribosomes
clusters of proteins and RNA molecules.
turkey vulture (Cathartes aura)-our local turkey vulture also shows sparse
hair- or fur-like "feathers" of the head .
kiwi feathers are convergent in the sense that these modified feathers function like
hairs... insulation.
The famous bacterium, Thermus aquaticus,
he original source of thermostable DNA polymerase (Taq polymerase) used in PCR.
earliest known mammals were very small and probably needed excellent;
hearing and olfaction
Many people think that the first feathers actually evolved as
heat trapping insulation.
It appears plants and fungi....
helped each other evolve onto land.
closest living relative to cetaceans (modern whales and dolphins)
hippopotamus (mostly herbivorous) -common ancestor was probably carnivorous or omnivorous.
Examples of atavism in humans
hirsutism, tails.
In the chromosomes, DNA is associated with special proteins called
histones that function in DNA supercoiling and regulation. -think of histones as molecular spools that the DNA can wrap around
Eukaryotes keep DNA coiled around proteins known as....
histones, so it looks like beads on a string.
Describe the first simple feathers
hollow cylinders
species more closely related to humans than chimps
hominins, early ones similar to chimps in body and brain size.
Which species started making symbols/cave paintings?
homo sapiens
Each pair contains a
homolog from the mother and a homolog from the father.
How was Darwin's ideas about evolution different?
homologies, fossil records, and other things explained by common ancestors, traits evolve randomly in a network and not on Lamarck's ladder.
During synapsis
homologous bits and pieces of the chromatids might (or might not) be exchanged (switched).
These are stop codons at; ----- this is very precise (very convincing) phylogenetic information!
homologous positions, in homologous exons, in homologous genes
when recreating phylogeny do not confuse....
homologous traits for convergent ones. Homologous: common ancestor. Convergent: similar by chance.
Example of floating bone in humans
hyoid bone.
What is represented by a node in phylogenetic tree?
hypothetical ancestor
What was important about the Late Heavy Bombardment?
icy comets and asteroids delivered water to the early Earth
Why hybrids usually sterile?
incompatible gametes with either parent species.
Tigers don't eat insects or mushrooms so why would a tiger genome include five chitinase pseudogenes
inherited from a distant ancestor that actually needed them)?
tendency to mutate might be
inherited; this is called evolvability.
Indell mutations
insertion/deletion mutations
Animals in North America thousands of years ago;
lions, rhinos, camels, mastadons, mammoths. and beavers (extinct)
Sometimes we can learn about adaptation by investigating the
loss of function... in this case pseudogenes.
Where did early tetrapods live? how did they move?
lush, coastal wetlands. used legs to move underwater.
chitin
main structural polymer in arthropod* and crustacean exoskeletons and forms the cell walls of fungi and molds.
Transcription
makes complimentary RNA strand to the DNA -introns removed from chain of RNA nucleotides.
Viruses can be very complicated and contain
many genes that encode proteins and elaborate structures.
In the fungal world, isomorphic gametes are produced by different
mating strains. We also see mating strains (neither female nor male) in other kinds of eukaryotes too e.g. various algae, various protozoans, etc.
How do we know archaea were also present at beginning of earth?
methane in rocks, with low fraction of carbon (produced biologically).
For simple growth, cells divide by a process called
mitosis.
Over half human genome is from ...........
mobile genetic elements
The base of the human spine corresponds, bone for bone, to the base of a
monkey's tail.
Each of the the domains (Bacteria, Archaea, and Eukarya) is thought to be
monophyletic.
the platypus is a
monotreme mammal... (oldest extant lineage of mammals) it lays eggs -sophisticated electroreceptors in its bill, for finding worms. venom on spurs.
range of uranium-lead dating
more than a million years.
synapsids group called cynodonts had new mammal like trait...
more upright stance
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.
