GEOL #1 EXAM (correct one)

What is uniformitarianism? How is it used in geology? Why is it so important?

Uniformitarianism = the present is the key to the past. We use it in geology to guide our thinking about the history of the Earth. If we can look at the physical conditions today we can figure out what they used to be and then what they will be in the future!

What are the primary earth spheres? What are the major attributes of each? Why is it important to understand how they interact? How do these interactions lead to cascades of cause-and-effect? What types of cascades are positive feedbacks?

Atmosphere: the air! Temp + circulation, Hydro/Cryosphere: water availability, change in sea level, heat circulation, Lithosphere: the ground, soil, tectonic activity, Biosphere: all living organisms at the surface of the Earth. It is important to understand how they interact with each other because they all affect each other! All Earth’s systems are connected.

If the interactions are super intense, then they create cascades, or if there are numerous interactions right after one another, then it can get out of control? A domino effect if you will. Mass extinction, albedo positive feedback

What is an environment? How do environmental conditions determine organisms’ adaptations?

An environment is the physical make-up of the area an organism lives in. It’s a habitat, it’s all the surrounding organisms that are competing for a specific organisms resources, it’s all the organisms that the organism eats, etc etc. Environmental conditions determine what is a favorable trait for an organism to have! Creates the conditions for adaptations. Stressors and pressure force organisms to adapt or die :(

What is a Darwinian Demon? Why is it impossible? In terms of energy use vs. adaptations, what is the ‘ideal’ for an organism? What are biological trade-offs?

The Darwinian Demon is an organism that is the strongest, fastest, and basically has a bunch of ideal traits for their survival. It is impossible because that takes up too much energy from the organism. There are energy limits! Concept that describes a “perfect” organism (adapted to its environment). They want less energy usage or the most efficient form of energy usage and adapting so they can be the most fit for their environment. This doesn’t mean the fastest or strongest - just able to thrive and be a fierce competitor for other organisms, optimize reproductive success so successful traits become more common. You typically can’t have armor and be super big - tortoises are large and have a shell but are SO slow. The body can only protect an organism in so many ways.

What is biological evolution? What modern evidence do we have for evolution? What is the process of evolution? What are the types of selection (3)?

Biological evolution = change! The change in inherited traits over successive generations in populations of organisms. Evidence = bones! We can see how organisms have changed throughout the fossil record – but more than that, it’s Anatomical/morphological similarity (shared ancestry/fossils), biogeography (moving), Genetic relatedness (DNA)

A trait adapts to become more favorable for its environment, it is passed down, offspring is produced (more than can actually survive – struggle), in the struggle the advantageous traits get passed down (natural selection). Directional (favoring one extreme), stabilizing (favoring the average), disruptive (favoring both extremes – leads to specialization or speciation

What are the non-adaptive forces of evolution (3)?

Mutation, Genetic drift (random loss), Gene flow (migration)

What are the 5 major types of geological evidence? How do they support our understanding of evolution?

Rocks (physical environment), fossils (body/trace/chemical), minerals, topography, geochronology (study of deep geologic time)

What is the difference between crust and lithosphere? What is the relationship of lithosphere and asthenosphere to tectonic plates?

Lithosphere = crust + upper mantle - behavioral (rheological) name for Earth’s layers, crust = physical rock type/composition of Earth’s layers. The lithosphere is the Earth’s hard, rigid, outermost rocky shell. The asthenosphere is a softer, more malleable layer that enables the dynamic movement of the tectonic plates. - heat from asthenosphere rises and allows for movement of plates

What are the three types of plate boundaries? The three types of convergent boundaries? What type of movement is involved in each type? What landscape features are associated with each type of boundary?

Divergent, convergent, transform. Convergent boundaries: ocean-continent, ocean-ocean, continent-continent. Subduction, crumpling, crust running into each other and the older, denser one typically sinks. Volcanoes! Mountains with continent-continent

Why do species disperse? What are some mechanisms of active vs passive dispersal?

Species disperse because of environmental pressures or stressors forcing them to move - competition, previous environment destruction, mates, food availability. Active dispersal is when organisms move on their own (ex swimming, walking, flying) to a new place, move out of own power Passive is when another force moves them (ex wind moving pollen around) External force

What conditions (parameters) are likely to change during dispersal? How do organisms’ tolerances determine their ability to disperse?

Temperature, food type/availability, climate, topography. If they have a stenotype tolerance, they will have less ability to disperse as their bodies cannot handle the change as well as others, whereas eurotypic tolerance types are typically more successful because they can handle a wider range of tolerances

What are bridges to dispersal? What are barriers? What are some examples of each? How can something be both a bridge and a barrier?

Bridges = something that helps an organism disperse, barriers = something that hinders organism dispersal. Example of a bridge: land connectivity – land bridge, habitat connectivity – corridors. Example of barrier: (the opposite of a bridge) land separation – rising sea levels. A land bridge could be a bridge for a terrestrial organism but not a primarily marine-dwelling organism. It depends on what focal organism you are looking at.

How do barriers lead to increased biodiversity (hint: why is there initially one type of hippo in the Mediterranean, but after the Messinian drying event, there are two)?

Barriers force organisms to adapt. Their physical habitat disruption causing changes to food availability made the hippos change their body size due to less & different food available. Barriers could also move organisms to a different climate/temperature region, maybe even different topography like the horses, forcing changes to their physical morphology = increased biodiversity

What does ‘distribution’ mean for a given species? What three major components determine a species’ distribution?

Spatial “footprint” of a given organism (where we find a species). Geographic area, habitat type, spatial structure of individuals (patchy, random distributions)

What is the niche concept? What is the difference between a fundamental and a realized niche? What mechanisms are involved in each niche type?

Niche = the set of conditions an organism needs to persist. Fundamental niche = theoretical limits/tolerances of an organism. Carbon acquisition, oxygen demand, light requirements, temperature regulation, salinity control, moisture requirements

Realized niche = Actual limitations imposed on an organism (smaller range). Food availability & acquisition style (trophic level, carrying capacity), interspecific interactions (competition, predation)

What are some ways morphology is shaped by niche (rules/patterns)?

Colder environments = larger body types (Bergman’s rule), colder environments = shorter appendages (Allen’s rule), hotter/humid environments = darker color coat/fur/body (Gloger’s rule), more food = larger bodies (Guthrie’s/Geist’s rule), When trapped on islands body sizes get smaller compared to mainland and vice versa (Foster’s/Island rule)

What spatial patterns of species distribution do we observe? How do spatial patterns of distribution change through time?

Climate = temperature and latitude – Latitudinal Diversity Gradient (LDG) & Elevational Diversity Gradient (EDG) – shows where organisms will inhabit based on their comfortable latitude/elevation and temperature threshold. They change over time as the temperature and climate change over time (not sure what else to say here?)

What is a habitat? A biome? How do habitats/biomes change through time? What are the spatial and temporal (time) scales of those changes? What are examples at each scale?

Habitat is synonymous with environment – physical conditions of an area (temp, salinity, moisture, substrate, vegetation) specific tangible places where life interacts directly with the physical environment

Biome = a global mosaic of habitats – large-scale ecological units composed of multiple habitats (regional climate, distinctive flora/fauna). Habitat change: local, regional, global (specific listed below); biome change: moisture, insolation, topography, rock types and soils, types of vegetation. Local change: storms, floods, fires, droughts – short term, regional: sea level change, climate shifts – intermediate, global: super continent formation, long-term climate change, evolutionary innovations – deep time

What are the major drivers of Cenozoic cooling (3)? Describe how each one leads to global cooling. What drove drying in North America? Globally? What advantage did C4 plants have over C3 plants in these cooler, drier climates?

Rise of Himalayas + fall of atmospheric CO2 (continent-continent convergence, silicate weathering), Opening of the Drake Passage (change in ocean circulation bringing cooler air), Rise of Rocky Mountains (Rain Shadow (orographic) effect). C4 plants don’t do as much photorespiration – need less water to thrive – suitable for drier & hotter environments. They are abrasive and less fibrous

What were the characteristics of the mammoth steppe? What types of organisms populated the mammoth steppe? What evidence do we have for this biome? What caused the steppe to collapse? What was the impact on mammoths?

The biome was cold, dry, and grass-covered. MEGAFAUNA populated the mammoth steppe

We know this due to rock records, ice core records, pollen records, SedDNA records all supporting that it was very cold in the Pleistocene. The collapse was due to the AMOC collapsing and then restarted bringing pooled heat North causing rapid warming & thawing. It was excessively humid and the mammoths couldn’t adapt :( they died

What is the story of horse evolution during the Cenozoic? What features help us reconstruct this story? How do these features help us determine the timing of the change from closed canopy to open grassland biomes?

Horses used to have Brachydont hypsodonty, so a small crown-root ratio. They also had Bunodont morphology due to eating fibrous, soft vegetation. Over time, we see their teeth start to change to a higher crown-root ratio with hypsodont hypsodonty due to the gritty vegetation that had taken over the landscape. They also now had plagiolophodont morphology which is suitable for abrasive vegetation. We can see the timing of the change is around 20 Mya, which correlates with the timing of C4 grasses becoming more abundant due to a drier landscape, and forests dwindle rapidly. More grasses meant horses teeth had to evolve to fit the landscape

What is the story of the draining and refilling of the Mediterranean (Messinian Salinity Crisis)? What is evidence for this major environmental change? How did it impact mainland hippo species?

Plate tectonics shifted around the island of Cyprus along with fluctuations in sea level + rise in salinity. At 5.9-5.4 Mya there was an influx of salt meaning that there was land connecting the island and the mainland! The mainland hippo species stayed the same while the island hippo got smaller.

What is vulnerability? What are the three components in determining a taxon’s vulnerability? Change in what types of environmental parameters might cause organisms vulnerability to increase (e.g. temperature extremes…)? How do we assess an organism’s vulnerability?

Vulnerability = the degree to which a species, population or ecosystem is likely to be harmed when exposed to a stressor. Determined by exposure, sensitivity, adaptive capacity. Climate change - extreme weather, flood, droughts, rise in temperatures, rise in sea level, anthropogenic activities. V = E+S - AC

What is the PETM? How did plants and insects respond to change during the PETM? Why is it an important analogue to today?

PETM = Paleocene-Eocene Thermal Maximum - short period of intense fast global warming. Plants became less nitrogen-dense/less nutritious, and insects started eating more of them! They also (along with terrestrial organisms) moved poleward. We are probably currently going through a PETM…