Chapter 18 Vocabulary Flashcards
Darwin
19th century scientist who is best known for his theory of evolution by natural selection.
Evolution**
Change in the inherited traits of organimss over time.
Galapagos islands
Group of 16 islands lying off the west coast of South America that Darwin visited during his voyage on he Beagle and that are home to giant to giant tortoises and Darwin’s finches.
Natural Selection**
Process in which lviving things with beneficial traits survived longer and produce more offspring so their traits increase in a population over time.
Theory of Evolution by Natural Selection
Theory first proprosed by Charles Darwin stating that inherited traits of organisms change over time becauce organisms with beneficial traits survive longer and produce more offspring so their traits increase in frequency.
Absolute Dating**
Any method of dating fossils or rocks (Ex: carbon-14 dating) that gives the specimen an approximate age in years.
Fossil**
Preserved remains or traces of an organism that lived during an earlier age.
Molecular clock
Molecule such as protein or DNA that is compared in different species to gauge how recently they shared a common ancestor.
Paleontologist
Scientist who studies fossils to learn about the evolution of living things.
Relative Dating**
A method of dating fossils based on their position in rock layers that determines only which fossils are older or younger but not their age in years.
Vestigal Structure**
Inherited structure that is no onger used but is still rpesnt in a modern organism who inherited it from an ancestor that used this structure.
Allele Frequency
The number of copies of an allele divided by the total number of alleles for the gene in a gene pool.
Coevolution
Evolution of two interacting species in which the evolution of traits in one of the species results in the other species evolving matching traits.
Convergent Evolution
Independent evolution of the same traits in species that live in similar habitats.
Gene Flow
Change in allele frequencies in a gene pool that occurs when genes move into or out of the gene pool because individuals migrate into or out of the population.
Gene Pool**
All the genes in all of the members of a population.
Genetic Drift
Change in allele frequencies in a gene pool that occurs by chance in a small population.
Macroevolution*
Change in inherited traits of organisms that occurs over a long period of time above the level of species.
Microevolution*
Change in inherited traits of an organism that occurs over a relatively short period of time at the level of the population.
Population
A group of individuals of the same species that live in the same area; unit of microevolution.
Speciation
Evolution of a new species.
Cenozoic Era*
The last era of the geologic time scale that began 65 million years ago and continues to the present and is called the age of mammals.
Extinction
The complete dying out of a species.
Geologic Time Scale**
Tool for understanding the history of Earth and its life that divides Earth’s history into eons, eras, and periods on the basis of major changes in geology, climate, and the evolution of life.
Last Universal Common Ancestor (LUCA)
Cell that existed about 3.5 billion years ago and gave rise to all of the present/following life on Earth.
Mass Extinction
One of six similar events in history of life on Earth during which the majority of species died out.
Mesozoic Era*
The era of the geologic time scale that lasted from 245 to 65 million years ago and is called the age of dinosaurs.
Paleozoic Era*
Era of the geologic time scale that lasted from 544 to 245 million years ago and during which most major groups of multicellular organisms evolved.
Precambrian*
Supereon at the beginning of the geologic time scale that lasted from 4.6 billion years ago when Earth formed to 544 million years ago and during which life first evolved on Earth.
Amniote
Animal such as a reptile or bird that produces eggs with waterproof membranes.
Aquatic
Type of plant tha tlives in the water (Ex: water lily, cattail).
Chordate
Animal with a notochord, post-anal tail, dorsal hollow nerve cord, and pharynegeal slits; animal in Phylum Chordata.
Coelom
Fluid-filled body cavity found in many invertebrates and all vertebrates that is completely enclosed by mesoderm.
Cranium
Bony skull that encloses and protects the brain of a vertebrate.
Exoskeleton*
A non-bony skeleton that forms on the outside of the body of many invertebrates including insects and other arthropods.
Notochord
Rigid rod that runs along the length of the body and is a defining trait of animals in Phylum Chordata.
Pseudocoelom
Partial, fluid-filed body cavity not enclosed by mesoderm that is found in some invertebrates such as roundworms.
Segmentation
Division of an animal’s body into multiple parts/segments.
Symmetry*
Trait of an organism that can be divided into two identical halves; may be radial or bilateral.
Terrestrial
Of or relating to an animal that defends a given area, or territory, typically including its nest and enough space to feed itself and its young.
