Midterm 2 Flashcards
Species Variability
Each species has its own morphological variability, and we can group those variabilities into three categories: Ontogenetic, Genetic, Nongenetic
Ontogentic
variability in the result of the organism growth during its lifetime.
three stages, juvenile, adult, gerontic
genetic variability
has to do with the genetic structure of the specimen, it can either be continuous or discontinuous
Nongenetic
primarily induced by ecological factors, example: suprapopulations in bivalves, they was was no space to grow so they squished each other and as a resulted, the morphology changed.
ontogenetic trajectory
growth can be plotted to track morphological change; put it on a chart and measure the changes; empirical analysis
types of ontogentic variability
Isometric: organism shape remains the same during the ontogeny. (Just an increase in size)
Anisometric: organism shape changes (shape changes through time and if we plot the different values of 2 parameters then we will see that they are aligned according with a curved line, this parameters show what changes)
5 growth strategies in ontogenetic variability
Accretion- adding identical layers to its body in concentric form; ex: bivalve
Addition- added layers one segment at a time ex: echinoderms and radiolarians
Molting- As the organism grows the hard body part doesn’t grow with it, organism breaks out of the carapace and there is a “detachment line” ex; trilobites.
Modification- relative size of the bones makes us change ex: vertebrates
Mixed- more than one growth pattern happens in one organism; cephalopods (accretion addition and modification)
continuous variability
type of genetic variability that occurs continuously in the whole population of the species and cannot be explained by external/environmental factors
discontinuous variability
rare case, common in cases of differentiated sexes where there is changes without any transition between them.
example: planktic foraminifers (dexitral (left) vs. sinistral (right) coiling)
sexual dimorphism
female and male within the species are easily distinguishable and there is a sharp gap between the morphologies but it is harder to find these differences in fossil species.
agglutinant foraminifera
case of non genetic variability, this organism builds its tests with things in the environment, so the variability is environmental rather than genetic
Biases of paleontological (fossil) record
Fossilization bias- organisms destroyed/not part of the fossil record so none or fragmentary tests remain
Areal bias- fossils could be spread out but only one part of the fossil basin is collected due to funding limitations
sampling bias- only one portion of a layer is continuously sampled
Holotype
specimen designated to be the representative of the species, and is chosen by the author. It will have all the characteristics of the species (the best specimen of the species)
Paratype
the rest of the specimens from the biological population after the holotype has been chosen, chosen by the author
neotype
if the holotype was destroyed, a new one must be chosen after the original is proven to be destroyed
how do you select a holotype
it is a subjective method of choosing.
lectotype
species was described but the author did not select a holotype. This occurs to fossils that were described before the type classification was made in the 19th century
paralectotype
remaining specimens after the lectotype selection
type locality vs. type level
type locality- finding a species in a geographical location on earth
type level- finding a species somewhere in the geological timeframe of the earth
Textilaria Americana
example of author not naming a holotype, a lectotype being chosen then the original samples being rediscovered
Morphospecies
Species defined by their morophology. Essential question: how do we know see the differences between individual species when there are some overlap.
need for specialists in morphospecies
specialists are needed when you cannot tell the morphological differences of a specimen
the differences between biology, paleontology and genetics
Biology- Species can reproduce with themselves, but cant cross breed
Genetics- Species is defined as the isolation genetic code
Paleontology- Species is defined in relation to time, where the species came about and so forth. Centered on the evolution in space and time.
how do the 3 sciences deal with the mechanisms that create new species
- paleontology: deals with the effects of the these mechanisms
- biology and genetics: deals with the process of the mechanisms
process of classification of evolutionary process
morphology- grouped by common ancestry
polyphyly- grouped by morphology
paraphyly- grouped partly by common ancestry, only reflect the evolutionary process partly
systems of classification
essentialism/typological- organisms are grouped together based on morphoplogy ex: linean classification system
nominalism- the classification of groups and the organisms that exist in nature are just a product of the human mind. Theory never really used, put forth by Lamarck
empiricism- taking into account all morphological changes of an species, but could not explain how these morphologies came to be.
evolutionary classification- Charles Dariwn; it is possible to recognize the ancestral descent
holotype syndrome
specialists only illustrate speciments that resemble the holotype, neotype and lectotype and results in little new added info to get more information about the specimen.
type series
classifications that take into account the evolutionary process of the specimens
subspecies level
proposed by Charles Darwin, a level below species and therefore and formalizing the species heterogeneity
pioneers in the 3 branches of science
Ernest W. Mayr- biology
Theodosius G. Dobzhansky- genetics
George G. Simpson- paleontology
composite paleontological species
characteristics:
1. Monophyletic
2. morphological variability
3. morphologically heterogenous and discontinuous entity
4. has a developmental history that is traceable
5. existence can be tested
speciation and extinction
speciation- start of species evolution
extinction- end of the species
stratigraphic range
the interval between speciation and extinction
infraspecific categories
individuals of species clustered to form group populations
Allopatric
isolated populations
sympatric
when two or more populations area of distribution overlap over a certain geological time period
gradualism
Darwin’s theory of evolution, changes in species happening slowly over time; this happens when the parental species co-exist with the daughter species resulted in a variety of species
phyletic transition
when the emergence of the daughter species coincides with the extinction of the parent species
Monophly
grouping species according to the direct ancestor-descendant relationships
Polyphyly
formation of groups inconsistent with the ancestor-descendant relationships.
Paraphyly
includes only a part of the descendant species from a common ancestor.
evolutionary classification
started with Darwinism, it groups species in lineages not genuses. Grouped based on common ancestory and achievements in the evolutionary process.
why use lineages in evolutionary classification
lineage shows how unrelated organisms from separate ancestors evolved to look the same way
difference between linean and evolutionary classification
linean groups on morphological similarities while evolutionary classification groups based on common ancestry
typological classification has axiomatic character, while evolutionary classification is scientific
are lineages equal/identical
No, species can develop more than others, some will develop to a certain point and then stop
types of lineage
directional- continuous evolution between two or more features resulting in monophyletic-linear succession of species
branched- occurrence of at least one feature that creates a divergence
iterative- repetitive evolution of one or a group of features which leads to descendant species that considerably resemble each other and evolved from one common ancestor
condensed- fast evolution, with differences in morphology with the ancestral species, but little variability within the species
what are the dominant elements in life forms on earth
carbon, oxygen, hydrogen, nitrogen, sulphur, phosphorus
petroleum composition
???
living matter molecular composition theory
the proof life formed in aquatic regions, because the human body is 70-90% made out of water.
components of life forms
water, protein, fat, carbohydrates, DNA, RNA, ATP.
problems with typology classification
classification is mainly subjective and scientists disagree on the closeness of morphology
solar nebula theory (formation of the solar system
formation of the solar system. Started as a cloud of cosmic dust and gases. As it started to rotate the matter concentrated in the center. The center became hot, thermonuclear reactions turned the center into a star. Which also led to the formation of terrestrial planets.
formation of monomers
During the formation of the sun, lighter gases were expelled and heavier gases remained to form monomers
what are the oldest fossils
cyanobacteria known inn the Eoarchean period
what are monomers?
the dominant life forms today that existed in early atmosphere of earth in the form of biogenic elements. They were heavier than other elements in the atmosphere so were not expelled with the rest. They eventually combined to make molecular compounds.
the earth’s modern atmosphere
Modern earth’s atmosphere can’t be conducive to life because of its oxidizing climate
Ivanovich Oparin theory of the earth’s early atmosphere
the primordial atmosphere was reducing rather than oxidizing, because currently oxygen could not have existed without the existence of plants. The atmosphere provided inorganic substances that reacted with the soup to form the first life forms on earth. Before there was biological evolution there was chemical and biochemical evolution.
what is the Miller and Urey experiment
Miller and Harold C. Urey tried to recreate the original primordial soup, in lab conditions to see how the substances can react with each other.
ingredients: mixture of gases, water, heat, ultraviolet radiation,= organic molecules formed and amino acids were made.
did Miller and Urey create life in the experiment
no; and they never claimed to
what are the organic molecules occur frequently outside the solar system
hydrogen cyanide
thio-formaldehide
methanol
ethanol
what are polymers
monomers that are put together to make polymers through the process of polymerization
what is the process of amino acid polymerization
step 1: dehydration condensation: two amino acids molecules combine to form a dipeptide
step 2: dipeptide molecule combine to form a long polymeric chain, known as protein (polypeptide)
sugar polymerization, and why they could have existed in the primordial times.
sugar combined to make polysaccharides (carbohydrates)
these are stable in a reducing atmosphere which means they would have survived the primordial times.
Nucleic acid polymerization
- sugar and base create a nucleic acid,
- then the nucleic acid combines with a phosphate to make a nucleotide
- -combination of nucleotides make polynucleotide
difficulty with studying the emergency of life forms on earth
- there are few rocks that are 4.5+ billion years old
- high degree of metamorphic alteration of these rocks
- molecules do not fossilize
the 5 data sources that can be used to understand the life origins on earth
- rock record- helps understand what types of rocks occurred in the stratigraphic record which helps determine the chemical composition of the early earth.
- fossil record- direct evidence; although it is scarce
- chemical record- presence of chemical fossils
- experimental data- provide models for the emergence of life. example: how the chemical reacted to create monomers and polymers in the primordial soup
- extrapolation of biochemical and biological data from modern organisms- helps understanding the mechanisms led to the first life forms and morphological components of early life forms.
Isua formations as evidence of life on early earth ???
- located in Greenland
- Aged 3.8-3.9 billion years old
- Consisted of dark rocks- darkness is evidence of the existence of organic matter, because they needed organic matter to get that dark
- graphite: represent “fossilized” vestiges of primordial soup, because rock is made of organic material
- calcite minerals demonstrate that small amounts of molecular oxygen existed only in small amounts, so true layers of calcitic rocks could not form
what are 4 major processes of early earth surface formation
- Earth crust formation
- Early atmosphere formation
- Ocean formation
- Catastrophic meteorite bombardment
earth crust formation
crust formed due to differences in the temperature between earth and the cold outer space
early atmosphere
certain gases were removed and heavier gases stayed during the volcanic phenomena because of the magnetic field.
ocean formation
the existence of zircon 4.4 billion years ago is evidence that there were oceans on early earth because zircon needs sea-amounts of water to form. The hypothesis is that water originated from earth’s interior and condensed at the surface to form oceans.
catastrophic meteorite bombardment
many metetorite collisions due to the instability of the orbit of the planets and orbits in the solar system, explain the hypothesis that life formed several times but was destroyed due to these meteorite impacts, it was when the orbit became stable and meteorite bombardment ceased that earth became stable and permanent life formed
Evidence for the catastrophic meteorite bombardment
the craters on the moon and other planets show existence of some sort of collision. The highest frequency of impact tended to happen around the same time on various plantes.
Apex Chert
the lithological in a volcano-sedimentary formation in which the oldest fossils were found
How did they determine the age of the fossil found the Apex chert
they looked at the age of the rock above and below it to determine it was 3.4 billion years old
bacteria found in the Apex chert
bacterial resembling purple
cell-like structures made of carbon which resemble modern iron bacteria
Implications of the apex chert
- the bacteria or anaerobic organisms meaning they do not require oxygen to live, but from the modern bacteria, they are seen to be photosynthetic as well. This means the survived in the early reducing atmosphere and contributed to the transformation to an oxidizing environment
- this explains the formation of the crystals in the isua formation, the presence of oxygen dissolved in water was put there by a primitive life source.
- Because there was calcite in the Isua rock formations, there must have been oxygen in the environment. This indicates oxygen producing organisms because graphite results from the fossilization process of carbonization.
What was discovered in the Schieber Beach Cryptozoon?
- There was discovered stromatolites, which shows there were organism in the protorozokyic period. Noted as the “hidden animal”
2.
what period do the schieber beach cryptozoon belong to
between the Archean and Proterozoic period
where can the oldest stromatolites be found
In the Isua formation; 3.2 billion years old.
Pilbara Craton
questionable stromatolite fossils found in Swaziland and Australia
Characteristics of stromatolites
- They have different shapes that are influenced by the paleoenvironmental factors around them.
- growth is through accretion
- Hard to study because they do not belong in the fossil record
- They conquered majority of the waters of the earth
- They are groupings of individual bacteria and cynobacteria; the next step of evolution.
what are the 4 components of stromatolites
growth surface- oxygen producing photosynthetic cynobacteria and aerobic bacteria
Undermat- thin bacterial layer, non-oxygen producing bacteria, aerobic but can use oxygen when available. But this layer doesn’t produce much oxygen.
Oxygen depleted zone- dominated by anaerobic bacteria. This area has few organisms, and these anaerobic bacteria can survive extreme environments.
Stromatolite mass- this area doesn’t have any bacteria or cynobacteria in this area. Has mostly calcium carbonate.
Can the rock in the Apex chert be dated
No because they have gone through extreme forms of metamorphism, but the rock above and below the apex chert is well preserved so they use those two to determine the date.
smallest organisms found in the Apex Chert
Eoleptonema and Archaeotrichion
largest organisms found in the Apex Chert
Primavifilum and Archaeoscillatoriopsis
Stromatolite geological timeline
Eoarchean-Mesoarchean- earliest stromatolite
Neoarchean - stromatolites conquer most of the earth
Proterozoic- stromatolite dominance continues (for 2 billion years stromatolites did not have enemies)
post- Proterozoic/phanerozoic boundary- stromatolites suffer reduction because of evolution of the shelly fauna and molluscs
what is the Gunflint formation
formation that showed fossils of stromatolite that had diversified beyond the two primitive types: spherical and filamentous. which documents a major event in history of life: prokaryote diversification. they also tried to grow in size during the evolution (side note).
What proves the evolution of photosynthesis?
the presence of fossil bacteria and cynobacteria in the Apex Chert,
what was the result of the evolution of photosynthesis?
It resulted in more oxygen in the atmosphere.
Where did photosynthesis evolve?
In organisms in marine environments
what is the proof of existence of oceans in the banded iron formation?
The occurrence of ripple-marks and pillow-lavas in the rock. The Zircon minerals in Australia need vast amounts of water to form.
Is it possible to find the beginnings of the evolution of photosynthesis?
No because organisms older than the ones in the Isua formation are not known.
What does the Isua formation tell us about the early atmosphere?
The presence of calcite shows there was CO2 in the early atmosphere. The presence of iron oxides (banded iron formation) is evidence of oxygen in the atmosphere.
The formation of banded iron formations in the Isua formation
Volcanic eruption released iron into the atmosphere, the iron atmosphere combined with dissolved oxygen from the ocean. This is therefore evidence of molecular oxygen in the atmosphere and therefore bacteria and cynobacteria.
What are pyritic conglomerates and what do they indicate about the early atmosphere?
rock formations in the Proterozoic and Archean period that have pyrite and uraninite minerals. These minerals are highly susceptible to oxidization, and the fact that they are not oxidized means that 2.8 to 2.0 billion years the atmosphere was reducing (not always oxidizing).
what is anaerobic photosynthesis
the dominant metabolic strategy for organisms during the reducing atmosphere. It is the only way oxygen could be produced (because these organisms could produce oxygen but did not need it).
When did the atmosphere move from reducing to oxidizing
during the increase of stromatolites and bacteria which was Archean (end)/ protorezoic period.
what are red beds and what are their significant
accumulation of limestones in continental subaerial areas. The amount of limestone significantly increased from the during the Proterozoic period which is evidence of a change from reducing to oxidizing climate. because of their concentrations of iron oxides.
how did eukaryotes form, and what is the evidence for this.
Eukaryotes formed through the combination of prokaryotes through symbiosis.
what is/is the significance of the bitter spring formation.
The rock formation in which the first fossil eukaryotes groups were discovered. They know that these are eukaryotes because the organism was in the process of cell division which does not occur in prokaryotes.
what type of organisms were found in the bitter spring formation?
photosynthetic eukaryotes; green and red algae.
What is the difference between eukaryote and prokaryote reproduction
prokaryotes- go through multiplication in the nuclear membrane; asexual reproduction
eukaryotes- cell division; sexual reproduction. The imperfect combination in the gene pool is what fuels evolution.
what is Bangiomorpha?
- Red algae
- It represents a major leap in history of life. It is the first multicellular algae we know, represents the evolution of alga.
- Found in the Proterozoic-Quaternary.
- Attached to the sea floor and erect upward towards the sunlight
what is Torridonophycus?
- Green Algae
- In the Neoproterozoic
- Have cyst-like structures (thicka) that protect the cells during extreme environments
- Evidence that the earth was green, during the beginning stages of the continent.
what is Melanocyrillium?
- Show signs of the evolution of an animal metabolism
- Late Proterozoic
- Similar to foraminifers
what is grypania?
- multicellular filamentous, ribbon-like alga
2. Occur in paleoproterozoic and Mesoproterozoic
what is unique about the fossilization in the bitter spring formation
eukaryotes were fossilized in the process of cellular division, which shows expectational preservation of the nucleus
what do we mean by stromatolite persistence
When looking at the oldest stromatolite fossils and the modern day phyla, there was not much evolutionary change
Findings in the Grand canyon
plantonkic algae
What is the period which is reffered to as the “snowball earth”?
The period of the cyrogenian when earth was at low temp. covered in ice and snow. The life forms on earth were in danger of extinction.
Octavia
The oldest fossil we know.
what was found in the dua formation?
fossilized animal embryos.
who and when gave birth to the first multicellular organisms
eukaryotes birthed the first multicellular organisms during the late Proterozoic era.
Characteristics of eukaryotes
- existence of mitochondira, ribosomes, and plastids
2. well-defined nucleus and cytoplasm
The stages of symbiosis from prokaryotes to eukaryotes
- symbiosis of aneorobic bacteria and flagellate bacteria, to make a simple eukaryote
- symbiosis of organism in state 1 and bacteria that can breath oxygen= formation of mitochondria (Kingdom fungi and Animalia)
- symbiosis of organism in stage 2 and photosynthetic bacteria= formation of plastids. (Kingdom Plantae)
Discoveries of Ediacarans
- Has a high diversification of body plan which shows high adaption rate to the environment
- Exist int he Ediacaran /Cambrain boundary
- Worm-like structure, lacking exoskeleton and internal organs
- presence of cephalization; A cephalic shield evolved in the anterior pat of the worm-like body as if to protect would evolve to be the brain.
who is Martin Glaessner
provided the first interpretation of the Ediacaran fossils
what is Parvancorina?
A type of Edicaria fossil with bilateral symmetry and loose segmentation
what is Tribrachidium?
The first Edicara to have trilateral symmetry
what is Dickinsonia?
Ediacara with bilateray symmetry and defined segmentation, has a head and tail end, potential candidate for the ancestor of the trilobite
what is a charnia?
Ediacara, which is similar to Opticorin.
What is the Spriggina Case?
Ediacara that was discovered by Sprig. It had elongated body, with a head and tale end, cepheletic shield making one side heavier than the other, left an impression in the ground possibly from when it dove head fast into the sand at death.
What is the Kimberella?
Ediacara that is considered the ancestor of molluscs, because of its feeding process.
