Midterm 1 Flashcards
Fossils
remains of older life forms, vestiges of once living organism
Fossilization
process through which a living organism is turned into a fossil.
Bryophytes
simplest land plants, lack woody tissue and reproduce through spores
tracheophytes
higher plants with woody tissue, this is further separated into seed and seedless plants.
Protozoans (animal-like protistans)
diverse single-celled eukaryotes
Characteristics of foraminifera
- Animal like protistans
- solitary organisms
- cytoplasm protected with tests
- Tests have one (unilocular) or more (multilocular) chambers
characteristics of radiolarians
- animal-like protistans
- solitary
- mineralized structure (skeleton) protects the cytoplasm
- skeletal structure that provides highest quality fossil record, most elaborate skeletal systems among fossils
characteristics of ciliophorans
- Animal-like protistans
- single-celled
- solitary
- 2+ nuclei in the cytoplasm
- protect their body with a lorica
Choanoflagellates
- Animal-like protistans
- solitary or colonial
- poor fossil record
sponges
- The simplest multicellular animals on Earth
- Evolve tissue grades so they don’t have organs
- cylindrical shape with large opening at the top (osculum) and small pores that penetrate through the lateral walls
Feeding process of sponges
Structure of the body is made for filter feeding. The flagella create a current that enters the body through the pores and is expelled through the osculum
Poriferans
they distinct phylum that includes sponges
Sponges/poriferans internal skeletal composition
skeleton has small-sized spicules, they can be calcareous.
4 subclasses of phylum
Calcarea- calcareous skelton
Demospongea- skeleton consists of siliceous spicules
Hexactinellida- skeleton consists of siliceous spicules w/ 3 axes
Sclerospongia- calcareous skeleton with different skeleton architecture than calcarea
Cnidarians
characterisized by nematocyts; cells that release a deadly poison that can paralyze the prey
- they can either be sedentary generation or free-swimming generation
Lophophorates
characterized by a fan shaped organ that filter-feeding, known as lophophore. Two phyla: Bryozoa and Brachipoda
Bryozoa vs. Brachipoda -
Bryozoans- colonial
Brachiopods- most frequent in the fossil record, they protect their soft bodies with two valves. Brachiopods are subdivided into inarticulata which lack a hinge and articulata have a hinge with well-developed teeth
Molluscs
Organisms of the phylum Mollusca that are soft-bodied animals, often protected by a shell of CaCO3. they are one of the most important reef builders throughout the phanerozoic period.
Aplacophora
molluscs without hard body parts/no shell, they do not appear in the fossil record
Polyplacophoro
molluscus that have soft body parts protected by a number of plates that overlap each other, they appear in the Devonian period
monoplacophora
protect the soft body parts with one calcitic piece/shell, very similar to gastropods
gastropods
Molluscus that evolved in the Cambrian and are among the most diverse and abundant groups of organisms, the are adapted to aquatic areas and soft body parts are protected by twisted shell
Cephalopods
molluscs with tentacles around the mouth (octopi and squid) shell is external in nautiloids (octopi and squid) and internal in some squid.
Scaphopods
class of molluscs that are tapered and elongated shell that protects the soft body, tentacles around the mouth that help catch prey.
Bivalvia
class of molluscs were soft body is protected by 2 symmetrical or asymmetrical valves, they do not have a head and like much movement.
anthropods
- organisms that have limb segmentation
- protected by calcitic structure which makes them easy to fossilize
- in aquatic and terrestrial areas
- among the earliest conquerors of land
trilobites
subphylum of anthropods body is covered in calcified carapace which has a protective role. Carapace is divided into three parts: cephalon, thorax and pygidium.
chelicerates
subphylum of arthropods they have anterior (near the head or front) appendages (smaller parts that are connected to the larger body) and these appendages turn into chelicerae.
Crustaeans
Ostrocods - subphylum of arthropods soft body is protected by two calcareous valves and is adapted to aquatic environments, the low tolerance for environmental changes is a great for study of environmental changes in the past
insects
body is divided into three parts: cephalon, thorax and abdomen
echinoderms
the soft body is protected by a test consisting of a huge number of calcitic particles, called Ossicles, those remain in anatomical connection and when the organism is dead the test disintegrate and the organic matter dissolves- so when there is an enchinoderm fossilized (fossil taxa) it is almost considered a case of exceptional preservation.
water vascular system of echinoderms
helps the muscles control the organisms movement
symmetry of echinoderms
in first phases of evolution they had little symmetry or no symmetry but as they evolved they have pentameral symmetry and sometimes have bilateral symmetry superimposed by over the pentameral one.
echinoderms are unique invertebrates
they are the most evolved invertebrates, because they have internal cavities with two openings and have embryonic stages of chordates rather than like other invertebrate groups
grapolites
colonial, were first very attached to the sea floor but then they floated up to the top and were spread out across different environments by waves and have great ability to adapt to environment.
structure for the grapolite colony
separated into one or more branches called tipes. The individual are structured along the stipes in a cup-like structure called thecae
cephalochordates
organisms with notochords, these organisms are known in the fossil record only in cases of exceptional preservation. They are ancestors of the conodont animals which have mineralized chewing apparatus
vertebrates
axials skeleton which is of bony or cartilaginous nature most evolved life forms on earth; agnathans, fishes, amphibians, reptiles, mammals, and birds.
Agnthans
vertebrates without jaws and are filter feeders
Fishes
the most successful groups of organisms, crossopterygian fishes invaded the land in the late Silurian and are considred the ancestors of the firs land vertebrates.
amphibians
most primitive land vertebrates; respiration is mixed and reproduction is through eggs.
Reptiles and birds
reptiles- cold blooded, , dominated by terrestrial vertebrates
mammals
- warm blooded
- give birth to living offspring
- evolution of consciousness (humans)
rate of fossilization
the ratio of dead organisms that became fossils
fossils vs. subfossils
- Fossils- before the ice age 11,700 yrs
subfossils- post ice age fossils
2 types of fossil representation
Hard body- most common type of fossilization
soft body- rare fossilization because of organic decay and trophic levels but can happen in instances of rapid burial
3 types of fossils
- physical remains of the dead organism
trace- preserve organisms activities, like feeding and movement chemical- part of the dead organism reacts with the minerals from environment
oldest fossil
Laqueus- brachiopod was found among the ancient Egyptians, a shell worn by the ancient Egyptians; 4000 yrs ago.
Xenophanes
first to record about fossils in the time of Greek rationalism “earliest known paleontologist”
xanthus
- fossils as a result of decreasing sea level
Lucius. Apuleius.
The Golden Ass. 2 AD - Fossils are a result of transportation of invading sea waters from other continents.
dark ages
major setback in terms of knowledge of fossils
georg bauer
Pioneer in the idea that fossils should be illustrated rather than described; focused on their shape; figured stones
Christopher Encelius
- first person to illustrate fossils
conrad gesner
first monographic study on fossils (first focused study on fossils)
subdivisions of paleontology
- ) vertebrate paleontology-study of evolution of multicellular organism that have vertebrates
- ) invertebrate paleontology- study of evolution of multicellular organism that don’t have vertebrates
- ) paleobotany- study of plant fossils
- ) micropaleontology- study of microscopic fossil debris I.e fish teeth
- ) Palynology- study of reproductive organs in higher plants; spore and pollen grains
- ) Paleoalgology- study of microscopic fossil algae
Sediments vs. Rocks
Sediments- unconsolidated particles
rocks- solid bound minerals
where can fossils be found
sediments or rocks
Three types of rocks
Igneous rocks- formed from molten lave under earth’s surface; usually doesn’t have fossils
Sedimentary rocks-on top of earth’s crust under normal temperature conditions
Metamorphic rocks-transformation of pre-existing igneous, sedimentary, or other metamorphic rocks under high pressure; during the formation process the rock remains in solid state.
sedimentary rock subdivisions
detrital rocks- formed through clastic rock formation cycle. weathering and erosion of pre-existing rock (fossils occur in these rocks)
chemical rocks
rocks that form in uppermost portion of the crust through precipitation from supersaturated solutions.
biochemical rocks
majority of rock is composed of hard parts of organisms, low diversity in chemical composition
Formation of detrital rocks
- Transportation of sediments to the sediment basin
- Deposition at the sediment basin
- lithification- (formation of rock which involves compaction, cementation and recrystallization)
2 major categories of chemical rocks
carbonates and evaporates
Difference between Aragonite and Calcite
Similar in composition differ in mineral structure.
evaporates
- ) most common minerals halite gypsum and anhydrite
2. ) evaporites accumulate in shallow waters in warm/arid climates
Which chemical rock are fossils more likely to be found in and why?
Carbonates more likely; there are many species in the region were these rocks form
higher sedimentation rates in the regions the form in. Evaporates not so much because the environments that they form in are restrictive interms of species.
examples of biochemical rocks
reefal limestone- rock that dominated by the fossils of reef builders
chalks- accumulation of microscopic forms of algae
What is a protolith?
the original rock from which a metamorphic rock formed
What types of metamorphism happen in relations to activities in the earth’s crust
regional- transformation that happens in plate collision zones
contact- ‘’ in proximity of igneous intrusions
burial- ‘’ in large sedimentary basins (sedimentary piles accumulate)
high and low pressure- in regions of subduction
what are the degrees of metamorphism and which degree is most and least likely to contain fossils
low, medium, and high grade
low- most likely to have fossils
medium and high- less likely because they are partially melted
Process of fossilization
- permineralization
- recrystallization
- moldic preservation,
- replacement
- carbonization
- impregnation
- impression
- congealment
- dehydration
- amber and tarpits
Perminieralization
A process of fossilization in which, organisms with hard bodys and with internal porous structure absorb minerals from environment preserving the original nature of the organism (frequent)
Recrystallization
A process of fossilization that happens most often with organisms that have calctic hard body parts. The shells and porous internal structures of the organism are destroyed by the recrystallization and cannot be observed anymore.
Moldic Fossilization
the dissolution for hard parts of the fossil after contact with chemically reactive fluids. When the chemical fluids entering the pores or cracks of the surface. and the hard part is dissolved, an empty space is left in the rock and this preserves the morphologic features of the fossil.
cast in moldic fossilization
outer rock preserves the external features of the fossil
mold in moldic fossilization
rock infill forms that preserve the internal features of the fossil
Replacement
the empty space created in the rock after the dissolution of the fossil, is filled with newly precipitated minerals. These minerals enter through the rocks pores and openings.
carbonization
Most common type of fossilization in plants and invertebrates. When dead body expels certain elements i.e oxygen, nitrogen, etc… as it starts to decay but carbon remains and then at temps below 225 degrees c, the organism is fossilized into a dark crystalized structure.
Impregnation
when the organism that dies in areas of high consentration substances (calcium carbonate) and the soft tissue absorbs the substances and becomes rigid
impressions
rapid burial occurs which preserves the shape of sometimes the internal structure of the organism, so soft body parts can be preserved in this process. Best preservation occurs if the impression is made right away before the organism decays
congealment
At high altitudes with areas of permafrost, best situation for soft body preservation.
Dehydration
In desert areas the dead organism’s fluids are equally dried out and the remaining structure can be preserved if covered with sand in a process of mummification
fossilization of amber
the best full body preservation, thick and viscous substance that is why small organisms can be completely enclosed in it. From this scientists can pay a good attention to it.
fossilization of tar pits
occurs where petroleum ascends from the crust and are oxidized to create a vicious material that can trap and preserve organisms
mixed fossilization
In plants carbonization and permineralization can co-occur, but the most complex situation only 4 types of fossilization can occur in an organism: permineralization, carbonization, impregnation and impressions.
Exceptional Preservation
This occurs when there is rapid burial and anoxic areas
Lagerstatten -
sites of extrodinary fossil presevation they are almost “snapshot” in time.
which processes of fossilization can lead to exceptional preservation?
fossilization in amber and tarpits, dehydration, congealment
preservation of colour patterns is an example of what type of fossilization
exceptional preservation.
what are the 4 eons
Hadean- earth was molten rock
Archean- the oldest rocks on earth
Proterozoic- longest eon that had mainly microscopical life
Phanerozoic- normal size organisms emerge in fossil record
3 eras of phanerozoic eon
Paleozoic, Mesozoic, Cenozoic
Periods of the Paleozoic Era
Cambrian, Ordovician, Silurian, Devonian, Carboniferous (Mississippi and Pennsylvanian), Permian
Periods of the Mesozoic Era
Triassic, Jurassic, Cretaceous
Periods of the Cenozoic Era
Paleogene, Neogene, Quaternary
Boundary between Hadean and
Boundaries is between Hadean and Archean is the oldest rock which is 4.08 billion yrs
Boundaries between Proterozoic/Phanerozoic -
boundary is the processes that led to the massive development of exoskeletons
Sir William Smith
principle of inclusion: the xenoliths (external rocks that have become part of the existing rock formation) are older than the rock that embeds them
principle of cross-cutting relationships
cross-cutting younger than the cross-cut rock
isotopic method
using radiometric dating to date rock, by looking at the radioactive decay rate
the five kingdoms
Kingdom Bacteria- simple organisms without a nucleus or cytoplasm, prokaryotes
Kingdom Protista- eukaryotes, simple celled organism with a nuclei and cytoplasm, and external or internal protective structure
Kingdom Fungi- fossilized plant roots rhizoliths and endoliths, but the type vary
Kingdom Plantae- photosynthetic, multicellular eukaryotic organisms; higher algae with woody tissue and larger bodies
Kingdom Animalia- most evolved organisms on earth, multicellular eukaryotes
binomial vs. trinomial
bionomial- two names
trinomial- three names
Original Linneaean hierarchy
Kingdom, class, order, genus, species
improved Linnaean hierarchy
kingdom, phylum, class, order, family, genus, species
modern linaean hierarchy
kingdom, phylum, subphylum, superclass, class, subclass, infraclass, superorder, order, suborder, infraorder, superfamily, family, subfamily, tribe, subtribe, genus, subgenus, species, subspecies
Prokaryotes
most primitive organism in the fossil record; without a well-defined nucleus and are solitary and colonial
Effect of prokaryotes on the evolution of life -
The bacteria they develop using their life cycle changed the atmosphere from reducing to oxidizing which allowed the evolution of eukaryotes and sexual reproductive mechanisms.
Characteristics of Algae (plant-like protistans)
- live in aquatic environments
- uni or multicellular with a defined nuclei in the cytoplasm
- lack mineralized parts put bodies are commonly impregnated with calcium carbonate at death because of the aquatic environment.
Red Algae (Rhodophyta)
Oldest algal group -· different pigment, most primitive of the algae, first that evolved out of multicellularity, they grow as attachments of other living and non-living organisms, major oxygen producers of on earth
Green Algae (Chlorophyta)
photosynthetic and occur in waters with solar energy, resemble the higher level plants. Occur in the Proterozoic era.
Charophyta
- multicellular
- occur in brackish or tropical climates
- no mineralized parts
- reproductive process includes females producing the egg and letting it be filled with calcium carbonate to make it rigid and give it a protective structure. (commonly in the Paleozoic era)
Kingdom Plantae
autotrophic photosynthetic organism, evolved as a result of invasion of terrestrial environments
