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이 집합의 용어 (27)
Macroevolution refers to evolutionary changes above the species level, observed over large time scales, such as the emergence of terrestrial vertebrates and mass extinctions.
Abiotic synthesis is the formation of organic molecules from inorganic precursors without living organisms, a key early step in the origin of life.
A reducing atmosphere is rich in electrons/hydrogen and lacks free oxygen; early Earth had this atmosphere, enabling abiotic synthesis of organic molecules.
The RNA world hypothesis proposes RNA was the first genetic and catalytic molecule, capable of self-replication and catalysis before DNA and proteins evolved.
A protocell is a fluid-filled vesicle with a membrane-like structure that may have been a precursor to living cells, showing simple growth, reproduction, and metabolism.
Ribozymes are RNA molecules that catalyze reactions, including making complementary RNA copies, supporting the RNA world hypothesis.
Endosymbiosis is the process where a prokaryote engulfed another cell that evolved into mitochondria or plastids, leading to eukaryotic cells.
The fossil record is the collection of fossils in sedimentary layers documenting organism changes over time, though it is incomplete.
Relative dating determines fossil age by their order in rock strata, showing which fossils are older or younger but not exact ages.
Radiometric dating measures the absolute age of fossils by decay rates of radioactive parent isotopes into daughter isotopes.
Half-life is the time for 50% of a radioactive parent isotope to decay into its daughter isotope, e.g., Carbon-14 has a half-life of 5,730 years.
An eon is the broadest division of geologic time, including Hadean, Archaean, Proterozoic, and Phanerozoic.
An era is a subdivision of an eon; the Phanerozoic eon includes Paleozoic, Mesozoic, and Cenozoic eras.
Stromatolites are layered rocks formed by prokaryotes binding sediment, representing the earliest evidence of life about 3.5 billion years ago.
The oxygen revolution was when atmospheric O₂ rapidly increased due to photosynthesis, causing extinctions and enabling aerobic respiration.
Prokaryotes are single-celled organisms without a nucleus, including bacteria and archaea, dominant for over 1.5 billion years.
Eukaryotes have cells with a nucleus, membrane-bound organelles, and cytoskeleton; oldest fossils date to 1.8 billion years ago.
Serial endosymbiosis hypothesizes mitochondria evolved before plastids via multiple engulfment events, supported by bacterial-like features in organelles.
The Cambrian explosion was a rapid diversification of animal phyla about 535–525 million years ago, with new predation and defense adaptations.
Plate tectonics is the theory that Earth's crust is divided into plates moving over the mantle, causing earthquakes, mountain formation, and continental drift.
Mass extinctions are events where many species rapidly go extinct worldwide, often triggered by global disruptions like volcanism or meteor impacts.
Adaptive radiation is rapid evolution of many new species filling ecological niches, often after mass extinctions or new habitat colonization.
An ecological niche is the role and environmental conditions a species occupies; niches left open after extinctions can be filled by adaptive radiations.
Heterochrony is evolutionary change in the timing or rate of developmental events, affecting body shape and form.
Paedomorphosis is a type of heterochrony where reproductive development accelerates, causing adults to retain juvenile traits of ancestors.
Homeotic genes are master regulators determining where body features develop, such as wing or flower part placement.
Hox genes provide positional information in animal embryos; changes in their expression can alter body part locations and lead to evolutionary changes.