Earth's Origin and Evolutionary Processes V.2

Plate tectonics

Theory of crustal plate movement on Earth.

Lithosphere

Earth's outer crust and upper solid mantle.

Asthenosphere

Molten upper portion of Earth's mantle.

Supercontinents

Landmasses that were once joined together.

Reproductively isolated

Species unable to interbreed due to separation.

Paleontologists

Scientists who collect and classify fossils.

Fossil Record

Evidence of life's history and evolution.

Sedimentary rock

Rock formed from sand, silt, or clay.

Fossil formation conditions

Requires no air, quick burial, hard parts.

Relative dating

Determining age by comparing fossil layers.

Index Fossil

Recognizable species existing briefly and widely.

Radiometric dating

Determining age via radioactive decay.

Half-life

Time for half of radioactive atoms to decay.

Geologic time scale

Timeline of Earth's history divided into eras.

Precambrian Time

Covers 88% of Earth's history.

Paleozoic Era

Era beginning 544 million years ago.

Cambrian explosion

Rapid diversification of multicelled animals.

Permian extinction

Largest mass extinction, 90% marine species lost.

Mesozoic Era

Era beginning 245 million years ago.

Cenozoic Era

Era from 65 million years ago to present.

Anthropocene Epoch

Current epoch marked by human impact.

Early Atmosphere

Contained cyanide, CO2, CO, nitrogen, H2S, and water.

Formation of Water

~3.8 billion years ago, oceans formed on Earth.

Liquid Water

Essential for the evolution of first life forms.

Miller and Urey Experiment

Produced amino acids, suggesting organic molecule formation.

Photosynthetic Bacteria

First organisms to release oxygen into the atmosphere.

Rising Oxygen Levels

Led to extinction of anaerobic life forms.

Endosymbiotic Theory

Eukaryotic cells evolved from symbiotic prokaryotes.

Mitochondria

Primitive aerobic bacteria that produce ATP.

Chloroplasts

Evolved later through endosymbiosis, involved in photosynthesis.

Evidence for Endosymbiosis

Mitochondria and chloroplasts have bacterial-like DNA.

Darwin's Theory of Evolution

Modern organisms descended from ancient organisms over time.

Scientific Theory

Well-supported, testable explanation of natural observations.

H.M.S. Beagle Voyage

Darwin's 5-year journey that informed his evolutionary hypothesis.

Darwin's Key Observations

Adaptations, survival traits, and fossil evidence noted.

Galapagos Islands

Different environments led to varied species adaptations.

Common Ancestry

Species on different islands evolved from a common ancestor.

James Hutton

Proposed Earth shaped by slow geological forces.

Charles Lyell

Geological processes remain constant over time.

Jean-Baptiste Lamarck

Proposed species change over time, adapting to environments.

Survival Traits

Certain traits enhance survival and reproduction.

Fossil Evidence

Fossils resemble living organisms, indicating evolutionary links.

Lamarck's Hypothesis

Traits acquired during life can be inherited.

Natural Selection

Mechanism for evolution proposed by Darwin.

Inherited Variation

Differences among species crucial for evolution.

Artificial Selection

Humans select traits from natural variations.

Struggle for Existence

Competition for resources among species.

Biological Fitness

Ability to survive and reproduce successfully.

Survival of the Fittest

Better-suited individuals survive and reproduce.

Common Descent

All species descended from common ancestors.

Fossil Record

Evidence of life changes over geological time.

Geographic Distribution

Similar species evolve similar traits in different areas.

Homologous Structures

Similar internal structures indicate common ancestry.

Similar Embryology

Closely related species share embryonic development stages.

Primates

Group of mammals with shared characteristics.

Cerebrum

Part of the brain enabling complex behaviors.

Binocular Vision

Ability to perceive depth using both eyes.

Flexible Digits

Adaptation for tool use and climbing.

Australopithecus afarensis

Early hominid known as 'Lucy', 3.6 million years ago.

Australopithecus africanus

Larger skull than A. afarensis, 2.5 million years ago.

Homo habilis

Early human-like species, used simple tools.

Homo erectus

Nomadic species with advanced tools, 1.3-0.3 million years ago.

Homo sapiens

Modern humans with larger brains, 200-300 thousand years ago.

Hominid

Family including humans and their ancestors.

Evolution

Change in species over time through natural processes.