chapter 12

bio

naturalist

an expert in or student of natural history

comparative morphology

 analysis of the patterns of the locus of structures within the body plan of an organism. (the wings of a bird and dragonfly both serve the same function; they help the organism to fly.)

biogeography

the study of the geographic distribution of plants, animals, and other forms of life. 

catastrophism

the theory that changes in the earth's __crust__ during __geological__ history have resulted __chiefly__ from sudden violent and unusual events.

evolution

the process by which species adapt over time in response to their changing environment

adaptation

the biological mechanism by which organisms adjust to new environments or to changes in their current environment.

fitness

the condition or attribute of being fit, such as the suitability of an organism or a species to find a mate and reproduce offspring successfully

The degree of adaptation to an environment Measured by an individual’s relative genetic contribution to future generations

natural selection

 is the process in nature by which organisms better adapted to their environment tend to survive and reproduce more than those less adapted to their environment.

adaptive trait

A genetic trait that helps an organism to maximize its reproductive success.

A heritable trait that enhances an individual’s fitness

geological time scale

divides up the history of the earth based on life-forms that have existed during specific times since the creation of the planet.

mass extinction

when species vanish much faster than they are replaced

Radiometric dating

used to estimate the age of rocks and fossil by measuring the ratio of a radioisotope and daughter elements

Describe how fossils form

pressure and mineralization change remains to rock. exposed by the erosive forces of water and wind.

Half-life

Characteristic time it takes for half of a quantity of a radioisotope to decay into daughter elements

Pangea

supercontinent, formed about 237 million years ago, broke up about 152 million year ago

describe theory of plate tectonics

Earth’s outer layer of rock is cracked into plates

Slow movement rafts continents to new positions over geologic time

Earth's outer shell is divided into several plates that glide over the mantle.

Homologous structures

Vary in size, shape and function

Similar structure and internal elements

Same genes direct their development

Analogous structures

Body parts that appear similar and have the same function in different lineages, but evolved separately in different lineages

difference between homologous structures and analogous structures

Homologous structures share a common ancestry, but not necessarily a common function. Analogous structures share a common function, but do not share a common ancestry.

Morphological Divergence

Evolutionary pattern in which a body part of an ancestor changes in its descendants

Morphological convergence

• Evolutionary pattern in which body parts with same function evolved separately in different lineage

Comparative embryology

is the branch of embryology that compares and contrasts embryos of different species. It is used to show how all animals are related.

biochemical similarities that exist among organisms of different species.

an evidence of evolution of varied forms of life from a very distant common ancestor./

Photosynthesis, cellular respiration, transcription, and translationare all identical or very similar in various types of organisms.