Unit 15: Changes Over Time Vocabulary

Question 1

Survival of the Fittest

Answer 1

Also known as natural selection. Individuals who are best suited to their environment will survive and pass their genes on to the next generation.

Question 2

Struggle for Existence

Answer 2

Members of each species compete regularly to obtain food, living space, and other necessities of life.

Question 3

Homologous Structures

Answer 3

Similar body parts found in different species with different purposes. These body parts provide evidence that each of the different organisms developed from a common ancestor.

Question 4

Relative Dating

Answer 4

The science of determining the relative order of past events without necessarily determining their absolute age.

Question 5

Stabilizing Selection

Answer 5

Natural selection that favors the average individuals.

Question 6

Geographic Isolation

Answer 6

2 populations are separated by geographic barriers and evolve differently due to the separation.

Question 7

Coevolution

Answer 7

The process by which two species, for example, a flower and a pollinating insect, evolve in response to each other.

Question 8

Descent With Modification

Answer 8

Each living species has descended, with changes, from other species over time.

Question 9

Adaptations

Answer 9

A change or the process of change by which an organism or species becomes better suited to its environment.

Question 10

Analogous Structures

Answer 10

Structures that serve the same purpose in different species but evolved independently. In other words, these structures did not evolve from the same structures in a common ancestor.

Question 11

Absolute Dating

Answer 11

The process of determining an age on a specified chronology in archaeology and geology.

Question 12

Disruptive Selection

Answer 12

Natural selection that results in a change among the traits of a population in two directions; could lead to two new populations.

Question 13

Temporal Isolation

Answer 13

Occurs when 2 or more species reproduce at different times.

Question 14

Gene Flow

Answer 14

The movement of genes into and out of the population (immigration and emigration).

Question 15

Natural Selection

Answer 15

Also known as survival of the fittest. Individuals who are best suited to their environment will survive and pass their genes on to the next generation.

Question 16

Fossil

Answer 16

Any evidence of an organism that once lived.

Question 17

Vestigial Structures

Answer 17

Body parts that once had a purpose but are no longer functional and/or needed in a species.

Question 18

Speciation

Answer 18

Occurs when a group within a species separates from other members of its species and develops its own unique characteristics.

Question 19

Reproductive Isolation

Answer 19

Occurs when members of two populations cannot interbreed and produce fertile offspring.

Question 20

Convergent Evolution

Answer 20

The process by which unrelated organisms come to resemble one another.

Question 21

Genetic Drift

Answer 21

When allele frequencies in a population change as a result of random chance. Occurs more frequently in small populations.

Question 22

Artificial Selection

Answer 22

Also known as selective breeding. Nature provides the variation, humans select the variations that they find useful.

Question 23

Law of Superposition

Answer 23

Basic law of geochronology, stating that in any undisturbed sequence of rocks deposited in layers, the youngest layer is on top and the oldest on the bottom, each layer being younger than the one beneath it and older than the one above it.

Question 24

Embryology

Answer 24

The study of living things before birth.

Question 25

Directional Selection

Answer 25

Natural selection that results in a change among the traits of a population in one direction.

Question 26

Behavioral Isolation

Answer 26

Occurs when 2 individuals are capable of interbreeding but have different courtship rituals.

Question 27

Divergent Evolution

Answer 27

Accumulation of differences between groups which can lead to the formation of new species.

Question 28

Hardy-Weinberg

Answer 28

The five conditions necessary to maintain genetic equilibrium in a population: 1. No mutations must occur so that new alleles do not enter the population. 2. No gene flow can occur (i.e. no migration of individuals into, or out of, the population). 3. Random mating must occur (i.e. individuals must pair by chance) 4. The population must be large so that no genetic drift (random chance) can cause the allele frequencies to change. 5. No selection can occur so that certain alleles are not selected for or against. The formulas allow scientists to determine if evolution has occurred: p (squared) + 2pq + q (squared) = 1 and p + q = 1.