Chapter 3

 Common __________ theory: the universe existed as a concentrated single point, containing all known _______ and _________.  About _____ billion years ago this point began to expand and has stayed expanding ever since  Known as the _______ _______

 The young universe was ________ hot  It took about 1 million years for the matter in the _________ to cool enough for the first ________ to form.  Most new matter was _________ and _______ ▪ Simple elements ↑

 ______ began attracting helium and ________ atoms together  Matter became _______ as gravity pulled it together.  As density _________, the matter collapsed and ____________ under its own weight causing a warm, dense core called a ___________

 _________ continued to become denser until the _______ pressure and density were so high that ________ reactions began to occur  The nuclear ________ reaction from ____________ creates the stars  Nuclear _______: light atoms unite to form heavy atoms while releasing a _______ amount of energy  This is the same reaction that gives a ___________ _________its destructive power

 Once nuclear _______ begins, a star burns for millions of years and consumes the _______ within it.  As hydrogen becomes exhausted, the star’s core becomes _______.  It eventually ________ under the extreme gravity forces generated by the ______.  This may cause a large nuclear explosion called a __________.

 _______ stars account for the origin and distribution of ________ elements throughout the _________.

 Throughout the universe stars are clustered into ___________.  Our solar system is one of millions in the ____________ Galaxy.  The current __________ is that the solar system’s current form (with _______ orbiting the sun) began with a large cloud of _______ and _______ called a _________.

 The ________ of a ________ caused the nebula to _______, which caused it to spin.  As the cloud collapsed it became _______ and flattened into a disk due to the ________.  At the center a _________ developed which later became the sun.  Some gas continued to ________ around the sun, eventually _______ into masses too small to become ______ (so they became our planets)

 According to the __________ theory, Earth and the other planets formed through __________.  _________: process by which particles clump together because of _________.  Bigger mass (due to __________) = more gravity  More gravity = more mass being ___________.  The Earth was formed about __________ years ago.

 Earth’s growing mass caused its core to ________.  The process of density ___________ formed the layers of the Earth.  _____ heated and became molten liquid containing iron and ______ which sank towards the ______.  Lighter matter such as oxygen and ________ moved toward the surface.

 Most widely excepted explanation = _______ Theory  States that a _______ sized body about 1/3 the size of the Earth struck the Earth during its early ___________ and sent material into orbit forming the ________.  Scientists believe that this _______ kick started magma ___________causing tectonic plates and __________

 Early _______ had essentially no atmosphere.  Mainly ________ and helium  As the Earth ________ enough for the surface to _______ into a crust volcanoes formed and gasses released by volcanic activity _________ an early atmosphere  Water vapor, ______________, nitrogen

 Water ___________ formed clouds and then rain but it was _________ so hot that the rain boiled off when it hit the ground.  After ________ cooling, Earth’s surface allowed rain to ________ and the oceans formed.  Other theories or contributions to ocean formation:  ________ or other water sources from space contributed to water __________

 The process that allowed ______ to form began with the _____________ of the oceans.  Carbon dioxide dissolved into the young __________, leaving a ___________-rich atmosphere.  There was no oxygen in the early atmosphere  Oxygen entered the atmosphere about 1.5 billion years ago when ____________ organisms began using carbon dioxide and releasing oxygen.  ________, an oxygen molecule found high in the atmosphere, is important because it _________ life from ______________ radiation Overview

 ______ record indicates that life on earth ___________ in the shallows of the ___________  How is this known?  Scientists have found ___________ life fossils significantly older than the fossils of _________ life  Oldest marine fossils  ___________  Dated 3.5 billion years ago  ___________, photosynthetic bacteria  AKA blue-green __________  First oxygen producing __________  The oldest terrestrial fossils found have been dated at 1 _____________ years old

 It is not clear exactly how the first __________ that comprise the building blocks of life _____________.  Ideas: they could have originated from _________ or ultra violet light in the atmosphere  ___________ Miller and Harold ______ did an experiment to test this idea by discharging ________ within gases.  The experiment produced _________ acids

 The __________ molecules that living systems use to build _________.  The main point of these ___________ was that many basic ___________ used by living systems readily form under certain ____________.

 ___________ proposed that early Earth’s ocean acted as a “_______ soup” of simple compounds that are the building blocks of _____.  _________ and other complex molecular chains formed when shallow pools _________, concentrating the “soup.”  Driven by sun energy, first life arose in this “______” from increasingly complex _________reactions

 Scientists __________ that volcanic activity, meteorites, etc. were too __________ to allow life to develop in shallow surface pools.  Also, the __________ atmosphere would not have ___________ early life from the destructive influences of ___________ radiation.

 Scientists now __________ that life arose deep in the ocean, ___________ by water.  According to this _______:  Life __________ using chemical energy and heat energy from _________ vents on the ocean floor.

 ___________ = Spontaneous Generation  The origination of life from ___________ matter  Do you think _________ could occur today, in Earth’s __________ conditions?

 ____________: create organic chemical energy compounds from _________ compounds and an external energy source  First __________ appeared billion years ago  __________: rely on consuming compounds to obtain _________ energy

 ___________ began to break down carbon dioxide into __________ (cyanobacteria).  This raised the __________ in the atmosphere from ____ to its present _____  Why is ___________ important?  Oxygen reactions allow __________ to use chemical energy more effectively  Oxygen allowed the development of ____________

 Theory developed by Charles _________  Natural _________: the process by which organisms with _________ characteristics tend to lie longer and reproduce more  __________: an error in genetic code (DNA)  Over long periods of time natural _________ and _________ caused the development of all the different life forms

 Scientists classify ________ environments based on physical characteristics  ___________  Depth  _____________  Density  Latitude  ____________ from shore

 The ________ column portion.  Divided into two horizontal zones...  __________ Zone: water area between low tide and edge of the ___________ shelf  ___________ Zone: open water area beyond the ______________ zone. ▪ Further divided into ________ regions

 __________ zone: top layer that _________ penetrates  __________ zone: sunlight reaches but isn’t strong enough to ___________ life  __________ zone: deep water in _______ ocean  ____________ zone: even deeper water in oceanic __________  __________ zone: deepest water in the ocean ________

 _________ of the ocean – based on depth from _______ to open ocean  ____________ zone: zone that water splashes but does not remain ____________  ____________ zone: bottom area between the high and low tide mark  ____________ shelf: area beyond the ________ zone.

 Further divided into:  __________ zone: ocean bottom closest to shore  Outer __________ zone: ocean bottom out to edge of continental shelf  ___________ Zone: bottom along the continental slope down to deep open ocean ______  ________ Zone: deep open ocean bottom  __________ zone: deepest zone – below 6,000 meters (also called deep sea floor)

 __________: group of organisms that exist adrift in ocean currents  _________: important subgroup of plankton ▪ Is the _______ that float at the surface  _________: organisms that swim  Most __________ are nekton  Majority of nekton are ________  _________: organisms that live on or in the sea _____  Can move or be ________ (attached to the sea floor)

 Benthos are divided into:  __________: animals that live on the seafloor  _________: plants that live of the seafloor  _________: organisms that are partially or __________ buried in the seafloor ▪ Most ________ are... ▪ Deposit feeders: feed off _______ drifting down from above ▪ ___________ feeders: filter particles suspended in the water for food