Geological Time Scale Overview

Eon = A unit of time equal to a billion years Era = A division of time within an eon, but not fixed to a specific duration Period = A subdivision of an era, with its length determined by fossil evidence Epoch = A time period marked by a notable event

Mutation = A change in DNA sequence that can alter allele frequencies, but often has a small impact on evolution. Natural Selection = Wherein an allele either increases or decreases an organism's fitness, leading to changes in allele frequencies. Artificial Selection = The process of humans choosing desirable traits in organisms for breeding, leading to targeted changes in allele frequencies. Genetic Drift = Random fluctuations in allele frequencies in a population, particularly significant in small populations.

The change in beak size in a bird population due to random chance events = Genetic Drift The breeding of purebred German Shepherds with purebred Huskies to produce crossbreed offspring = Artificial Selection The evolution of green tree frogs in green vegetation environments for camouflage = Natural Selection The development of brown coloration in offspring of brightly colored parents due to a change in their genes = Mutation

<p>Paleozoic = Animals with exoskeleton (trilobites) became diverse Mesozoic = Age of reptiles in marine and terrestrial habitats Cenozoic = Age of mammals</p> Signup and view all the answers

<p>Mesozoic = Pangea existed; extinction of species in the Paleozoic era led to rapid evolution of life forms Cenozoic = Grasslands expanded and forests shrank; Homo sapiens started to evolve Paleozoic = Reptiles colonized land; First insect appeared and developed wings later on</p> Signup and view all the answers

<p>Mesozoic = Dinosaurs became extinct during the Cretaceous period; Archaeopteryx evolved, a combination of bird and reptile Paleozoic = Amphibians became diverse and moved inland Cenozoic = Grass species evolved; Animals fit to open landscape allowing the predator-prey relationship</p> Signup and view all the answers

<p>Hardy-Weinberg Equilibrium = A state where a population's genetic makeup remains constant over generations Allele = The variant form of a gene Evolution = Change in the genetic makeup of a population over generations Population = A group of individuals of the same species living in a particular area</p> Signup and view all the answers

<p>Cenozoic = Age of mammals; Pangea drifted dividing it into continents; Homo sapiens started to evolve Mesozoic = Age of reptiles; Dinosaurs appeared on land; Pterosaurs conquered the sky Paleozoic = Extinction of species; Gymnosperms replaced earlier plants; Amphibians became diverse and moved inland</p> Signup and view all the answers

<p>Pterosaurs = Flying reptiles that dominated the sky during the Mesozoic Era Ichthyosaurs = Marine reptiles that dominated the oceans during the Mesozoic Era Archaeopteryx = A transitional fossil that exhibits traits of both birds and reptiles Gymnosperms = Seed-bearing plants that dominated the land during the Paleozoic and Mesozoic Eras</p> Signup and view all the answers

<p>Predator-prey relationship = An interaction between two species where one species (the predator) hunts and consumes the other (the prey) Genetic makeup = The complete set of genes or genetic material present in an organism Natural selection = The process by which organisms better adapted to their environment tend to survive and reproduce more successfully Adaptation = A trait or characteristic that helps an organism survive and reproduce in its environment</p> Signup and view all the answers