Chapter 15

Front 1

evolution

Back 1

the process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth.

Front 2

theory

Back 2

a well-substantiated explanation of some aspect of the natural world that is acquired through the scientific method and repeatedly tested and confirmed through observation and experimentation.

Front 3

fossil

Back 3

the remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock.

Front 4

artificial selection

Back 4

the intentional reproduction of individuals in a population that have desirable traits. In organisms that reproduce sexually, two adults that possess a desired trait — such as two parent plants that are tall — are bred together.

Front 5

struggle for existence

Back 5

a natural history metaphor. It refers to the competition between living things to survive. This, and the similar phrase struggle for life, were used over 40 times by Charles Darwin in On the Origin of Species, and the phrase is the title of chapter 3 of the Origin.

Front 6

fitness

Back 6

an organism's ability to survive and reproduce in a particular environment. the more organisms produced, the higher it is.

Front 7

adaptation

Back 7

a physical or behavioral trait with a working role in the life of an organism that is maintained and evolved by means of natural selection.

Front 8

survival of the fittest

Back 8

the continued existence of organisms that are best adapted to their environment, with the extinction of others, as a concept in the Darwinian theory of evolution.

Front 9

natural selection

Back 9

when nature chooses the fittest organisms for survival. the process whereby organisms better adapted to their environment tend to survive and produce more offspring. The theory of its action was first fully expounded by Charles Darwin and is now believed to be the main process that brings about evolution.

Front 10

descent with modification

Back 10

over time and generations the traits providing reproductive advantage become more common within the population.

Front 11

common descent

Back 11

describes how, in evolutionary biology, a group of organisms share a most recent common ancestor. There is evidence of this - that all life on Earth is descended from the last universal ancestor.

Front 12

analogous structure

Back 12

similarity of function and superficial resemblance of structures that have different origins. For example, the wings of a fly, a moth, and a bird are analogous because they developed independently as adaptations to a common function—flying.

Front 13

homologous structure

Back 13

is an example of an organ or bone that appears in different animals, underlining anatomical commonalities demonstrating descent from a common ancestor. In other words, it's when very different animals have bones that appear very similar in form or function and seem to be related.

Front 14

vestigial organ

Back 14

A rudimentary structure in humans corresponding to a functional structure or organ in ancestral animals.

Front 15

rudimentary

Back 15

of or relating to an immature, undeveloped, or basic form.

Front 16

hypothesis

Back 16

a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.

Front 17

theory of acquired characteristics

Back 17

the concept that modifications that occur during an organism's lifetime are passed on to its offspring. His example was the giraffe.