PHYS203 Exam Study Guide-Questions 2025/2026
with 100% Correct Solutions
Paleogeology
Study of ancient geosphere and Earth's history
Paleogeologist
Scientist studying ancient geosphere
Rock Record
Information about Earth's history recorded in rocks
Relative Dating
Determines events order without specific time
Absolute Dating
Reveals specific time of events in Earth's history
Stratum
Layer of lithified sedimentary rock
Law of Superposition
Lower strata are older, higher strata are younger
Principle of Original Horizontality
Sedimentary rock forms horizontally
Principle of Cross-Cutting Relationships
,Events cutting across strata are more recent
Fossil
Remains of ancient organism lithified into rock
Index Fossils
Fossils indicating specific time periods
Precambrian
First 4 billion years of Earth's history
Paleozoic Era
Era of ancient life, follows Precambrian
Mesozoic Era
Era of middle life, follows Paleozoic Era
Cenozoic Era
Era of recent life, follows Mesozoic Era
Rock Cycle
Continuous transformation of rocks
Molten Earth Formation
Earth initially formed almost entirely molten
Differentiation
,Separation of Earth into core, mantle, and crust
Microcontinents
Felsic parts of lithosphere forming small landmasses
Subduction
Oceanic plates sinking beneath continents
Primitive Lifeforms
Earliest evolved organisms in Earth's oceans
Unicellular microorganisms
Primitive lifeforms like bacteria and blue-green algae.
Invertebrate animals
Organisms like jellyfish, dominant in the Paleozoic Era.
Jawless fish
Primitive fish like certain species of eel.
Cartilaginous fish
Evolved from jawless fish, examples include sharks and rays.
Bony fish
Evolved from cartilaginous fish, like tuna and salmon.
Amphibians
, Vertebrates that transition from underwater gills to lung breathing.
Reptiles
Vertebrates that breathe air with lungs after hatching from eggs.
Mammals
Vertebrates that give live birth and feed young with mammary glands.
Platypus
Modern mammal that lays eggs but is still classified as a mammal.
Endothermic
Mammals that regulate body temperature independently of the environment.
Ectothermic
Animals that rely on the environment for body temperature regulation.
Lungfish
Vertebrate with both gills and lungs, like the modern lungfish.
Primates
Highly intelligent mammals including monkeys, gorillas, and humans.
Homo sapiens
Modern humans, evolved roughly 200,000 years ago.
Evolutionary progression
with 100% Correct Solutions
Paleogeology
Study of ancient geosphere and Earth's history
Paleogeologist
Scientist studying ancient geosphere
Rock Record
Information about Earth's history recorded in rocks
Relative Dating
Determines events order without specific time
Absolute Dating
Reveals specific time of events in Earth's history
Stratum
Layer of lithified sedimentary rock
Law of Superposition
Lower strata are older, higher strata are younger
Principle of Original Horizontality
Sedimentary rock forms horizontally
Principle of Cross-Cutting Relationships
,Events cutting across strata are more recent
Fossil
Remains of ancient organism lithified into rock
Index Fossils
Fossils indicating specific time periods
Precambrian
First 4 billion years of Earth's history
Paleozoic Era
Era of ancient life, follows Precambrian
Mesozoic Era
Era of middle life, follows Paleozoic Era
Cenozoic Era
Era of recent life, follows Mesozoic Era
Rock Cycle
Continuous transformation of rocks
Molten Earth Formation
Earth initially formed almost entirely molten
Differentiation
,Separation of Earth into core, mantle, and crust
Microcontinents
Felsic parts of lithosphere forming small landmasses
Subduction
Oceanic plates sinking beneath continents
Primitive Lifeforms
Earliest evolved organisms in Earth's oceans
Unicellular microorganisms
Primitive lifeforms like bacteria and blue-green algae.
Invertebrate animals
Organisms like jellyfish, dominant in the Paleozoic Era.
Jawless fish
Primitive fish like certain species of eel.
Cartilaginous fish
Evolved from jawless fish, examples include sharks and rays.
Bony fish
Evolved from cartilaginous fish, like tuna and salmon.
Amphibians
, Vertebrates that transition from underwater gills to lung breathing.
Reptiles
Vertebrates that breathe air with lungs after hatching from eggs.
Mammals
Vertebrates that give live birth and feed young with mammary glands.
Platypus
Modern mammal that lays eggs but is still classified as a mammal.
Endothermic
Mammals that regulate body temperature independently of the environment.
Ectothermic
Animals that rely on the environment for body temperature regulation.
Lungfish
Vertebrate with both gills and lungs, like the modern lungfish.
Primates
Highly intelligent mammals including monkeys, gorillas, and humans.
Homo sapiens
Modern humans, evolved roughly 200,000 years ago.
Evolutionary progression
