Science EOG Day Four: Earth Science

Geologic Evolution Who was Alfred Wegener Geologist who proposed continental drift & pangea Define: Pangea Super continent or large landmass once connected What is Continental Drift? The process by which continent gradually split apart from one large landmass Define: Tectonic Plates Large pieces of continental or ocean crust Define: Lithosphere The uppermost layer of Earth made of crust & mantle Define: Asthenosphere The soft layer of mantle The layer on which the lithosphere rests Explain the Theory of Plate Tectonics geologic evolution A theory that states that Earth’s lithosphere is broken into tectonic plates that move and change position over time The Theory of Plate Tectonics

Plate Boundaries: Plate boundaries are the places were two tectonic plates meet. Movement of Plate Boundaries Boundary What happens Use arrows to show the direction Convergent Plates push toward each other Divergent Plate move pull away from each other Transform Plates slide past each other Plate movements and changes on Earth’s surface Subduction: two oceanic plates push one is pushed under the other What happens? Formation? Oceanic Plate to Continental Plate Ocean plate sinks under continental Volcanic mountains Two continental plate collision Buckle and push upward mountains

A. Earthquakes & Volcanoes  Plate movements cause most changes in the Earth’s surface.  Earthquakes and volcanoes can also cause sudden changes in the Earths surface. Definition Type of Plate Movement Volcanoes Opening of the Earth's crust through which magma is released Convergent Subduction Earthquake The shaking of the Earth’s surface releasing stored energy from the pressure of rocks Transform Hot Spots An area of volcanic activity in the middle of a plate **most volcanoes and earthquakes occur in the outer rim of the Pacific Ocean. This area is called the Ring of Fire**

A. Erosion **the earth’s surface can also be changed slowly by the forces of erosion** Weathering is a force that also shapes the Earth’s surface Weathering (erosion) Process in which rocks are broken down into smaller pieces through the action of wind, water, roots, and animals Mechanical weathering Breaks rocks apart without chemical changes Examples:windWater Plant roots Animals burrowing Chemical weathering Wears away land and changes rock chemically Examples:AirWaterSaltsacids

Geologic Time: The geologic time scale is like a calendar that begins with the formation of the Earth. It is divided into 4 different categories. Define each: eon, era, period, epoch Eon Largest division of timeEra 2 nd largest unit of geologic time Mass extinctions mark the boundariesPeriod Smaller units that divide eras Rock formations mark the boundariesEpoch Smallest unit of geologic time Which is the oldest and largest geologic period? Precambrian What were some of the first organisms on Earth? unicellular organisms Unicellular – multicellular – early life forms – fish – insects – amphibians Reptiles – mammals/dinosaurs – birds – flowers – Mammals - humans

Fossils: imprints or remains or organisms that were once alive On what type of rock do fossils form? sedimentary Why? Igneous rock would destroy fossils Other ways that fossils form Petrified Minerals enter Openings in plants, Bones or shells Molds and casts Mold – impressions in rock (cake pan) Cast – shape of the fossil Carbon films Visible layers an image Trace fossils Evidence of animals presence Footprints, trails, holes, feces Preserved in tar, amber, ice Preserve original remains (actual body parts of organisms) Fossil formation: layers of sediment build up over dead organisms. Time and pressure turn them into rock

Determine the Age of Rocks Absolute Age: the actual age of a rock or fossil or how long ago an event occurred   Radioactive Dating: Measuring the age of a material using the amount of radioactive form of an element in a rock or fossil   What is the benefit of absolute age? Gives the most precise measurement (when possible)   Relative Age: Describes the age of an object or event compared to another object or event   Law of Superposition: In undisturbed sedimentary layers, older layers or rock are at bottom and become younger as you go up   Unconformity: A missing layer of rock due to erosion

Fossils are Clues to the Past List 4 ways fossils can help us learn about animals that are extinct? 1.Show how species have changed over time 2.How different species related to one another 3.Provide data about sizes, shape, growth 4.Clues about climate Index Fossils: fossil of an organism that existed for only a short period of time Helpful in determining age of rock layers (relative dating) Ice Core: vertical or tubular columns of ice Name the two ways that ice core help us learn about Earth’s history? Understand how climate has changed over time Concentration of atmospheric gases

Define: extinction: species disappears from Earth “Extinction occurs naturally but sometimes major events cause rapid or sudden extinction” List 8 natural events that can cause extinction of species: temperature change Volcanoes Earthquakes Floods/droughts Land change Disease Starvation rainfall Extinction

Describe each human threat to extinction listed below: Habitat Destruction Loss of species due to loss of homes or rapid change in habitat Pollution Contaminated air, water, soil, food Overfishing Catching large numbers and not allowing fish to reproduce Climate Change Ozone depletion, greenhouse gases, Pollution affect climate disrupt natural cycles This are only a few examples, if you are presented with different examples use your knowledge and common sense

Evolution Theories Evolution: process of change over time Charles Darwin Jean Pierre Lamark Evolution theory: ACCEPTED Proposed theory of NATURAL SELECTION Evolution theory: Proposed that species acquire traits that are passed on from parents Explain it: Natural Selection: IMPORTANT THEORY THAT EXPLAINS THAT SPECIES BEST SUITED FOR THEIR ENVIRONMENT WILL SURVIVE TO REPRODUCE Theory explains how populations respond to changes in their environments Why are variations important to populations? Can lead to new species