The Origin and Characteristics of Life

Flashcards based on lecture notes covering theories on the origin of life, characteristics of living things, and the biological differences between plants and animals.

Life

The sum total of all the bodily activities being manifested by a living thing; a force of energy from which all the different worlds of activity could be expressed.

Divine Creation / Mosaic Theory

The theory that life was created by a supernatural power whom we call God, providing an explanation for something beyond human comprehension.

Abiogenesis Theory

Also known as Spontaneous Generation, this theory suggests that life originated spontaneously from non-living matter.

Cosmozoic Theory

Also known as the Interplanetary Theory, it states that life reached Earth accidentally from outer planets in the form of a resistant spore propelled by radiation pressure.

Marine Theory

A theory stating that life originated from the sea.

Philosophical Theory of Eternity

The theory that life has no beginning and no end, having been present since the very beginning of time.

Biogenesis Theory

The most widely accepted scientific theory (Naturalistic/Evolutionary), stating life resulted from a chain of chemical reactions forming living protoplasm that gradually modified into present forms.

Chemical Composition (Living Things)

Consists of $C, H, O, N$ in definite proportion organized into complex organic molecules with great molecular weight.

Anabolism

The constructive phase of metabolism in living things.

Catabolism

The destructive phase of metabolism in living things.

Irritability

The ability of an organism to react to stimuli; in animals, it is characterized by quick reactions due to the nervous system.

Intussusception

Growth that occurs from within, which is characteristic of living things.

Accretion

Growth by external addition, which is characteristic of non-living things.

Terminal Growth

Growth that occurs at the edge of the organ and is continuous through life, characteristic of plants.

Differential Growth

Growth where changes to body parts are proportional to age, characteristic of animals.

Cellulose

The substance that makes the cell wall of plants thick.

$NaCl$ (in Plants vs. Animals)

$NaCl$ is toxic to plants, whereas animal tissues bathe in a solution of it.

Locomotion

The capability of movement found in animals, whereas plants are generally stationary.