Important Terms

Here is a list of terms that will come up and are useful to know:
To return to the page you were on, click on the highlighted term.

Environmental Stress
Any environmental stress, like temperature range, rainfall, availability of food and water source, competition and predation cause an organism to develop and change over time in response to them. For example, many species were wiped out in the successive Ice Ages over the last million years. Thier habitats were changing and only those generalized enough would survive.

A selected trait which is shared by one (or two, rarely) species. Human's ability to speak is an apomorphous character. No other animal has the ability for conceptual language other than Homo sapiens (humans).

morphological character
Having to do with the overall physical structure and shape.

A shared character which aligns groups of organisms via common ancestor.

geographic isolation
Occurs when an organism is cut off from others of same species (parental species) for long enough to prevent interbreeding when and if the two groups are reunited. Geographic isolation results in the formation of new species, often quite quickly.

Convergent Evolution
Characteristics shared by non-related groups and species, i.e. wings of bats, birds and insects. The groups are not recently related, i.e. birds, mammals, arthropods are completely different taxa, however each has responded to some enironmental stress which resulted in adaptations for flight.

Literally meaning "two-footed", simply stated it refers to an organism whose primary mode of locomotion is to walk on the two hind legs.

Deoxyribonucleic Acid, the "blueprint" for an entire organism, that which genes are made from.

Neotony / Paedomorphism
A process by which an organism retains characteristics of an earlier form of development, often embryonic. In early stages of development may species share primitive characteristics, thus neotony offers a sort of guideline as to how much groups of organisms have diverged from one another. It can be a powerful mechanism for evolutionary change. A good example is that of a mexican salamander when conditions are unfavourable remains in it's tadpole like larvae stage through its whole life. It reproduces and dies without ever attaining the adult form and leaving the water.

I stole this from my Prof!
Can you guess which is the human?
Click here to find out!

Subcutaneous Fat
While not really a true type of fat, this terms describes the fatty layer which clings to the underside of the skin. Other apes do not have this, in the wild, their fat is in between organs in the body cavitity. In the case of humans this layer develops not only in and around the organs in the torso, but also spreads under the skin all over the body. It gives aquatic and semi-aquatic mammals their streamlined shapes. It gives us also a stream-lined shape!

Wallace Line
A "line", in the East Indian archipelago, named and placed by Victorian biologist Alfred Russel Wallace which separates the Asiatic fauna from the Australian fauna. The line is a deep ocean channel which has not had a land bridge even in the lowest sea stands.

Natural Selection
The process by which a species is shaped by the environment and sexual selection as criteriea.

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