Midterm Cards Flashcards
were dinosaurs slow and stupid?
agile, got smaller over time
did dinosaurs swim in the ocean?
no those are marine reptiles
era of the dinosaurs
mesozoic era
what are the periods of the dinosaurs
triassic, jurassic, and cretaceous
______, Mesozoic, _______
Palaeozoic, mesozoic, Cainozoic era
time if the mesozoic era
251-65 Ma
Ma
megaanom= million years ago
subdivisions of time
eons, eras, periods, epochs, ages
when did most dinosaurs go extinct?
end of cretaceous: 65.5 Ma
times of triassic, Jurassic, cretaceous
triassic: 251 Ma
Jurassic: 200 Ma
cretaceous: 145
end of cretaceous: 65.5
geology
study of earths materials and earths hisrtory
science
a changing body of knowledge obtained through systematic study and practice; a search for general laws of natural processes
components of scientific method
1) observation establishes question
2) hypothesis developed
3) observation/ experiments to test hypothesis
4) last surviving hypothesis is the conclusion
5) accumulated body of knowledge = scientific theory
fossils
any physical evidence of ancient life
2 types of fossils
body fossils
trace fossils
body fossils
direct evidence of body or body parts such as mineralized bones, or soft tissue (rarely)
trace fossils
indirect evidence such as tracks (footprints), feces, skin imprints, etc
body fossils vs trace fossils
- body fossils after organism has died
- trace fossils left continuously
- more trace fossils
3 criteria to become a fossil
1) rapid burial = to avoid scavenging, erosion, or other damage
2) preserved= in soft sedimentary rocks that aren’t changed too much
3) fossilized= to protect body fossils
dinosaur bone fossilization process
per-mineralized`
permineralized
1) decay of organic material opens up pores in the bone
2) pores are filled with mineral precipitates
3) bone minerals are gradually replaced
7 types of dinosaur fossils
1) bones and skeletons
2) eggs
3) gastroliths (gizzard stones)
4) feces (coprolites)
5) skin impressions
6) footprints and trackways
7) toothmarks
other evidence and data used in interpreting dinosaurs (4)
1) living relatives (birds)
2) rocks
3) computer modeling
4) other fossil groups
collecting specimens
- large and fragile bones
- exposed, if fragile then encased in plaster
- allows for safe removal to lab
preparing the specimens
bones prepared and reconstructed in lab, not the field
Mineral criteria (5)
1) naturally occurring
2) crystalline
3) solid
4) define chemical composition
5) inorganic (usually)
What is a rock?
Rock is a consolidated aggregate of minerals
3 types of rocks
Igneous, metamorphic, sedimentary
How to distinguish rocks
Mineralogy and texture
Igneous rock formation
formed from very hot liquid (molten rock - magma) that originated deep in earth and moved up towards surface
Types of igneous rock
Extrusion and intrusion
Extrusion igneous rock formation
Magma erupts on the surface and cools
Intrusion igneous rock formation
Magma stalls just below the earths surface and is later exposed
Sediment definition
Anything that gets moved
Timeline/process of sediments
- pieces break off (erosion)
- carried down by weather (transportation)
- dropped off somewhere (deposit)
Where does sediment often occur
Water becomes calmer, such as low-gradient river valleys, lakes or oceans
Why is sand a type of sediment
It’s a collection of broken down (weathered) materials transported from various sources: rocks and living things (shells, wood, bones)
Sedimentary rocks
As the sediments pile up, the earlier sediments are buried deeper, and are subject to high overburden pressure, and become more compacted. Various chemical changes take place, cementing the particles together, forming a sedimentary rock.
Lithification definition and steps
The process of comparcting and cementing
1) sediment build up
2) pressure build up from all the sediment
3) fused together to become rock
Metamorphic rocks
If sedimentary rocks are not uplifted, they can be buried deeper, and undergo chemical change due to higher temperature and pressures (a process called metamorphism). They then become metamorphic rocks.
What kind of rocks are these
Metamorphic (warping from the pressure)
What type of rock is this
Sedimentary (layers)
metamorphic rocks and mountains
Metamorphic rocks may also be uplifted to form mountains, then weathered and transported, etc. Otherwise, they may be buried deeper, then melted to magma (molten rock). Magma may be released to the surface as lava, forming a volcano.
label the rock cycle
a: weathering
b: transportation
c: deposition
d: sediments
e: lithification
f: sedimentary rocks
g: metamorphism
h: metamorphic rock
i: melting
j: magma
k: crystallization
l: igneous rock (intrusive)
m: solidification
n: igneous rock (extrusive)
o: uplift and exposure
what type of rocks is best to preserve fossils? and why aren’t the others?
- sedimentary
- igneous is too hot (maybe igneous extrusive rock ex ash falling and preserving body)
- metamorphic has too much pressure and will break up specimen
bones as particles
- bones in a geological sense are just oddly shaped grains of sediment, part of the rock cycle.
- They can be picked up and carried by water, or simply can be buried by other sediments.
- Fossilization is part of the process of lithification of sediments.
articulated fossil
full body fossil
chunkasaurs
fragment/ part of bone/ articulate
rocks and what they tell us about their environment
- Sedimentary rock types reflect their environments of deposition.
- In rocks made up of transported particles, the grain size tells us the energy level of the environment.
- Clays indicate very quiet water (lakes, ponds), whereas sands suggest more energy and gravels even more (e.g., river channel).
-The layers themselves can show old river channels, sandbars, etc.
types of sedimentary rocks
low energy = clay/mud (when lithified is shale and mudstone)
medium energy = sand (sandstone when lithified)
high energy = gravel (conglomerate when lithified)
best type of sedimentary rock to preserve fossils
low energy (high energy would break up fossil)
characteristics of best terrestrial environment to preserve dinosaur fossils
1) on land
2) quiet water
3) rapid burial (mudslide, volcanic ash)
4) low energy
what are the layers of the earth by composition
crust (light)
mantle
core (heavy- made of metal: iron and nickel)
what are the layers of the earth by physical properties
lithosphere
asthenosphere
outer core
inner core
lithospheric plates
the lithosphere is broken into a number of large plates and many more smaller plates that move on the ductile asthenosphere
3 types of plate booundaries
1) convergent
2) divergent
3) transform
convergent boundary
come together- subduction and uplift
what type of boundary is this
convergent
divergent boundary
go apart - magma coming up (volcanoes)
what type of boundary is this
divergent
transform boundary
side by side - still get stuck then pressure builds up until it releases (earthquake)
what type of boundary is this
transform
plate techtonics
the action of plates (spreading, subduction, faulting) causes movement and tectonic activity (earthquakes, volcanism, mountain)
why is plate tectonic important
- continents are parts of large plates and move with respect to one another
- plate tectonics directly affects all of the processes of the rock cycle
- plate history is therefore important in understanding evolution, fossilization, and other topics - the earth has changed
when did the world look like this?
early triassic: 251 Ma
separated through Mesozoic
when did the world look like this?
late jurassic: 145 Ma
when did the world look like this?
late cretaceous: 65.5 Ma
mesozoic tectonics
- early in the mesozoic, all the continents are together and sea level was low
- late in mesozoic, all the continents are separated and sea level was vey high
- separated dinosaurs to cause more diverse breeding and more species
- dinosaur fossils can also be found in water because of rising sea levels
Taxonomy why
TO DESCRIBE NATURAL CATEGORIES
Systematics why
To help understand relationships
Systematics
Ordering the categories in terms of relationships (evolution), not just similarity
Taxonomy
The procedure of naming things
Linnaean system subgroups
Kingdom, phylum, class, order, family, genus, species
What is a species
Modern biological species are defines in terms of ability to interbreed under natural conditions
-bio species concept
- morphospecies concept
Biospecies concept
Reproduce viable offspring
Morphospecies concept
Use different morphology (shape/structure) as indirect evidence that they do not interbreed
Natural selection based off of what observation?
1) more offspring are produced than can survive to maturity
2) variations exist among the offspring
3) offspring must compete with one another for food, habitat, and mates
4) offspring with the most favourable characteristics are more more likely to survive to reproduce
5) beneficial traits are passed [on to the next generation
Survival of the _________
Best adaptable in that environment
Utility of fossils in the study of evolution
1) fossils are their only direct evidence for the history of life on earth
2) when we look at fossils, we see the appearance of structures and forms (adaptations) that separates genera, species, etc.
3) some characters change more with new genera than others
Homologous
Minilarity of organisms from different species doe to their inheritance from a common ancestor. Features that share such similarities are said to be homologous - similar from common ancestor
Analogous
Features show militarily in form but have a separate evolutionary history - similar but not from same recent ancestor
Cladistics
Takes on organism (with a set of characteristics) and classifies other organisms by the degree to which they resemble the first one
Cladogram
Shows clades (branches) of how similar organisms are
Evolutionary novelties
Organisms in a Claude are grouped by similar structures that are hypothesized to be evolutionary novelties (changes inherited from a common ancestor)
Cladistics: assigning characters
Characters need to be useful for distinguishing between organisms. If all organisms in an analysis possess the same character, it cannot tell us about their evolutionary relationships
Parsimony
The explanation with the least necessary steps is probably the best one
Monophyletic groups
Organisms that share a more recent common ancestor to each other than other organisms
what caused early mesozoic climate?
1) Pangea causes high seasonality
2) as Pangea starts to break up (rift), there is substantial volcanic activity that leads to high levels of CO2 in the atmosphere = a warmer world
high seasonality
hot summers and cold winters, less stable weather
the climate in the cretaceous
Pangea breaks p and high sea levels means a warm climate
- dinosaurs flourish at the poles
how would low diversity occur in dinosaurs?
In Pangea, dinosaurs can mix, leading to wide distribution of families
what drove the diversification of dinosaurs
Pangea breaks up and dinosaurs (and vegetation) change separately, causing isolation and diverse evolution of species
dinosaur food (plants)
ferns, sphenopsids, gymnosperms, angiosperms
plants and dinosaurs
angiosperms evolved late in Mesozoic, just when herbivore dinosaurs rapidly diversified. Coprolite (poop) fossils indicate some dinos ate these but also gymnosperms. Dinos, birds, mammals, and pollinators all likely affected plant evolution.
The cladogram leading to dinosaurs
notochord, chordates, pikaia, add calcefied skeleton, vertebrates, add jaw, add lobbed fin, tiktaalik, add 4 legs, tetrapods, frog, add amniotic egg, amniote, mammals (synapsids), add two holes in head, diapsids, snakes,add socketed teeth, add antorbital fenetra (holes). archosars, pterasaurs, dinosaurs
