Chapter 18 Vocabulary

Question 1

Darwin

Answer 1

19th century scientist who is best known for his theory of evolution by natural selection.

Question 2

Evolution**

Answer 2

Change in the inherited traits of organimss over time.

Question 3

Galapagos islands

Answer 3

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.

Question 4

Natural Selection**

Answer 4

Process in which lviving things with beneficial traits survived longer and produce more offspring so their traits increase in a population over time.

Question 5

Theory of Evolution by Natural Selection

Answer 5

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.

Question 6

Absolute Dating**

Answer 6

Any method of dating fossils or rocks (Ex: carbon-14 dating) that gives the specimen an approximate age in years.

Question 7

Fossil**

Answer 7

Preserved remains or traces of an organism that lived during an earlier age.

Question 8

Molecular clock

Answer 8

Molecule such as protein or DNA that is compared in different species to gauge how recently they shared a common ancestor.

Question 9

Paleontologist

Answer 9

Scientist who studies fossils to learn about the evolution of living things.

Question 10

Relative Dating**

Answer 10

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.

Question 11

Vestigal Structure**

Answer 11

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.

Question 12

Allele Frequency

Answer 12

The number of copies of an allele divided by the total number of alleles for the gene in a gene pool.

Question 13

Coevolution

Answer 13

Evolution of two interacting species in which the evolution of traits in one of the species results in the other species evolving matching traits.

Question 14

Convergent Evolution

Answer 14

Independent evolution of the same traits in species that live in similar habitats.

Question 15

Gene Flow

Answer 15

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.

Question 16

Gene Pool**

Answer 16

All the genes in all of the members of a population.

Question 17

Genetic Drift

Answer 17

Change in allele frequencies in a gene pool that occurs by chance in a small population.

Question 18

Macroevolution*

Answer 18

Change in inherited traits of organisms that occurs over a long period of time above the level of species.

Question 19

Microevolution*

Answer 19

Change in inherited traits of an organism that occurs over a relatively short period of time at the level of the population.

Question 20

Population

Answer 20

A group of individuals of the same species that live in the same area; unit of microevolution.

Question 21

Speciation

Answer 21

Evolution of a new species.

Question 22

Cenozoic Era*

Answer 22

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.

Question 23

Extinction

Answer 23

The complete dying out of a species.

Question 24

Geologic Time Scale**

Answer 24

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.

Question 25

Last Universal Common Ancestor (LUCA)

Answer 25

Cell that existed about 3.5 billion years ago and gave rise to all of the present/following life on Earth.

Question 26

Mass Extinction

Answer 26

One of six similar events in history of life on Earth during which the majority of species died out.

Question 27

Mesozoic Era*

Answer 27

The era of the geologic time scale that lasted from 245 to 65 million years ago and is called the age of dinosaurs.

Question 28

Paleozoic Era*

Answer 28

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.

Question 29

Precambrian*

Answer 29

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.

Question 30

Amniote

Answer 30

Animal such as a reptile or bird that produces eggs with waterproof membranes.

Question 31

Aquatic

Answer 31

Type of plant tha tlives in the water (Ex: water lily, cattail).

Question 32

Chordate

Answer 32

Animal with a notochord, post-anal tail, dorsal hollow nerve cord, and pharynegeal slits; animal in Phylum Chordata.

Question 33

Coelom

Answer 33

Fluid-filled body cavity found in many invertebrates and all vertebrates that is completely enclosed by mesoderm.

Question 34

Cranium

Answer 34

Bony skull that encloses and protects the brain of a vertebrate.

Question 35

Exoskeleton*

Answer 35

A non-bony skeleton that forms on the outside of the body of many invertebrates including insects and other arthropods.

Question 36

Notochord

Answer 36

Rigid rod that runs along the length of the body and is a defining trait of animals in Phylum Chordata.

Question 37

Pseudocoelom

Answer 37

Partial, fluid-filed body cavity not enclosed by mesoderm that is found in some invertebrates such as roundworms.

Question 38

Segmentation

Answer 38

Division of an animal's body into multiple parts/segments.

Question 39

Symmetry*

Answer 39

Trait of an organism that can be divided into two identical halves; may be radial or bilateral.

Question 40

Terrestrial

Answer 40

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.