54 terms

J. H. Earth Science Chapter 14


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Theory that species have changed over time
Longest subdivision of geologic time
Time unit based on major, striking, and world-wide changes in types of fossils present - divides an eon
Shortest geological time unit; based on difference in life forms that vary regionally, such as from continent to continent - divides a period
Geologic time scale
Division of Earth's history into time units based on the lifeforms that lived only during certain periods; consists of periods, epochs, eras, and eons
Natural selection
Theory proposed by Charles Darwin to explain how species change over time - process by which organisms with characteristics that are suited to a certain environment have a better chance of surviving & reproducing than those that don't
Artificial selection
Breeding of certain species by humans for desired traits
Time unit characterized by types of life existing world-wide at the time - smaller division of geologic time after era
Group of organisms that normally reproduces only with other members of their group
Small, hard-shelled organsims that crawled on the ocean floor Three-segmented bodied organisms used as index fossils because they were widespread and individual species existed for a limited amount of time before becoming extinct
Paleozoic Era
Trilobites live in oceans, first land plants appear - Organisms with hard parts, fish, amphibians, reptiles, Pangea
Precambrian time
covers almost 4 billion years of Earth history, but little is known about the organism's of this time - Cyanobacteria produced oxygen becomes a major atmospheric gas shielding the Earth from ultraviolet rays, complex organisms, invertebrates
why so little is known about Precambrian time
it was so long ago, no fossil record, rocks have eroded and the rock cycle changed rocks by heat and pressure
possible causes of the mass extinction at the end of the Paleozoic Era
changes in climate, lowering of the sea level, volcanic activity, a larger asteroid or comet could have collided with the Earth
where most of life-forms of the Paleozoic Era lived
in the ocean
seed plants which first appeared in the Paleozoic Era; oldest plants - has seeds without protective coverings
era of "middle life" - Dinosaurs roam Earth, gymnosperms are abundant
most recent period in the Mesozoic Era
oldest period in the Mesozoic Era
northern part of Pangaea
southern part of Pangaea
fast-moving dinosaur
dinosaur thought to nurture hatchlings
winged animal resembling both dinosaurs and birds
milk-producing animals; first appeared in the Triassic Period
flowering plants; younger plants - seeds with a hard outer covering survived better because they were enclosed and protected - evolved during the Mesozoic Era and is dominant today
most recent era - Mammals are common, angiosperms are abundant
most recent period in the Cenozoic Era
climate change that allowed flowering plants to increase
where most marsupials live
animals with pouches
bones of cold-blooded animals have
bones of dinosaurs
resemble those of warm-blooded animals because they have no rings like cold-blooded animals
one of the earliest life-forms, blue-green algae that produces oxygen. The fossils called stromatolites
animals with backbones; appeared during the Paleozoic period
animals with no backbones; developed shells and other hard parts, leaving a rich fossil record
Adaptations in reptiles
allowed them to move away from water for reproduction - the development of a membrane-encased egg allowed reptiles to reproduce away from water, now can live in a greater variety of habitats than amphibian ancestors
Plants and animals first moved to land
during the Paleozoic Era
division of Earth's history
eons, eras, periods, and epochs, based on fossils
Plate tectonics and earth history
continents moving through time have influenced the environment of past organisms
how fossils relate to the geologic time scale
appearance, disappearance, or change in abundance and diversity of fossil organisms can be used to subdivide geologic time
how plate tectonics might lead to extinction
changes in Earth's surface that altered habitats could have caused organisms with traits less suited to the new habitat to become extinct
how the eyes of a trilobite fossils as index fossils explain various geologic time periods
no eyes = deep water, burrower / stalked eyes = burrower / eyes toward front of head = swimmer / eyes toward the back = bottom dweller
geologic events that ended the Paleozoic Era
mountain building, continental movement, closure of seas, spread of deserts
era, period, and epoch in which Homo sapiens first appeared
Cenozoic Era, Quaternary Period, Pleistocene Epoch
period of the most recent ice age
Tertiary Period
dinosaurs lived in this era
Era of the Ediacaran fauna
Oldest fossils--fossils of cynobacterium
The supercontinent that existed when all of the continents came together to form one large landmass
Why trilobites may have become extinct at the end of the Paleozoic Era
Plate tectonics changed the land and sea, or shallow seas disappeared where they lived, or a meteorite impact
organic evolution
environmental changes can affect an organism's survival
Phanerozoic Eon
Made up of Paleozoic Era, Mesozoic Era, Cenozoic Era
Homo sapiens appears
Cenozoic Era / Pleistocene Epoch about 140,000 years ago