history of life
Adaptation – A trait that helps an organism survive in its environment.
Example: A camel’s hump storing fat for energy in the desert.
Arthropod – An invertebrate with a segmented body, jointed legs, and an exoskeleton.
Example: A crab or a spider.
Extinction – The complete disappearance of a species.
Example: The dodo bird no longer exists.
Fossil – The preserved remains or traces of ancient organisms.
Example: A dinosaur footprint in a rock.
Gradualism – Evolution occurring slowly over a long period.
Example: The evolution of horses from small ancestors over millions of years.
Half-life – The time it takes for half of a radioactive substance to decay.
Example: Carbon-14’s half-life is 5,730 years.
Mass extinction – A rapid decrease in the number of species on Earth.
Example: The asteroid impact that killed the dinosaurs.
Microsphere – A tiny hollow structure that may have been a step toward the development of cells.
Example: Early cell-like structures found in ancient oceans.
Natural selection – The process where organisms better adapted to their environment tend to survive and reproduce.
Example: Giraffes with longer necks surviving better because they can reach food.
Population – A group of organisms of the same species living in the same area.
Example: A herd of deer in a forest.
Punctuated equilibrium – Evolution occurring in short, rapid bursts instead of gradually.
Example: New species of birds appearing quickly after an environmental change.
Radioisotope – A radioactive isotope used in dating materials.
Example: Uranium-238 used in dating rocks.
Radiometric dating – A technique used to determine the age of fossils and rocks using radioactive isotopes.
Example: Using carbon-14 to find the age of ancient bones.
Reproductive isolation – When two populations can no longer interbreed and produce fertile offspring.
Example: Different frog species having different mating calls.
Vertebrate – An animal with a backbone.
Example: A fish, a bird, or a human.