Theories and Themes in the Origin of Life

Biology

Biology

Comes from two Greek words 'bios' meaning life and 'logos' meaning reason or study; it deals with structures, functions and relationships of living things and their environment.

Divine Creation

The belief that life forms and everything in the universe were created through a supernatural power of divine being.

Extraterrestrial Origin

The belief that life originated on another planet outside the Solar System.

Panspermia Theory

Proposed by Swedish scientist Svante Arrhenius; states that organic molecules and microscopic life may have been brought to Earth from outer space by meteors or other extraterrestrial bodies.

Theory of Spontaneous Generation (Abiogenesis)

The belief that life arose from inanimate matter after Earth had cooled.

Early Earth's Condition

Lacked oxygen but was rich in inorganic molecules such as carbon dioxide, carbon monoxide, hydrogen and nitrogen.

Oparin-Haldane's Experiment

Known as the 'Primordial Soup Theory'; an energy in the form of lightning caused inorganic chemicals to react with one another, creating a soup of organic matter in the ocean that eventually evolved into early forms of life.

Miller-Urey's Experiment

A chemical experiment that simulated early Earth's atmospheric conditions and tested the chemical origin of life under those conditions.

Francesco Redi's Experiment

In 1668, Italian physician Francesco Redi conducted an experiment that involved using maggots that arose in decaying meat, concluding that life arose from living matter.

Omne vivum ex vivo

A dictum by Francesco Redi meaning 'all life comes from life'.

Microbiology

Field of science that deals with the study of microorganisms.

Cells

Also known as the basic unit of life; all living things are made up of one or more cells, and all cells arise only from pre-existing cells by cell division.

Levels of Biological Organization

The hierarchy of classification of biological structures, ranging from atoms at the bottom of the hierarchy to the Earth's biosphere.

Population

All the individuals of a species living within a specific area at the same time.

Community

Interactions of different populations with each other within a specific area at the same time.

Ecosystem

Consists of all the living things in a particular area together with the non-living parts of that environment.

Biosphere

The entirety of all living things and non-living things.

Flow of Energy

Nutrition is the process by which animals, plants and microorganisms acquire food; energy is the capacity to do work.

Energy Pyramid

Shows that about 10% of the energy from each trophic or feed level is passed on to the next.

Evolution

The change in the genetic makeup and physical characteristics of species over a period of time.

Adaptation

The mechanism in which organisms develop in order to adjust to the environment.

Theory of Evolution by Natural Selection

Proposed by Charles Darwin; presumes that organisms with more favorable traits would be more likely to survive and reproduce in a certain environment.

Lamarckism

Belief that each generation would grow slightly longer necks and pass that trait onto their offspring.

Structure and Function

Structure refers to the shape or form; function is the specific role of different cells that help them carry out their duties.

Ecology

The study of how organisms interact with each other and with their environment.

Ecosystem Components

Two components of an ecosystem known as biotic and abiotic factors.

Predation

One organism is feeding on another.

PREDATION

One organism is feeding on another. The organisms that hunts for the other organism is called predator, while the organisms being hunted is called prey.

COMPETITION

Organisms use and compete for the same limited resource at the same place at the same time.

INTRASPECIFIC COMPETITION

Competition among individuals of the same species.

INTERSPECIFIC COMPETITION

Competition among different species.

SYMBIOSIS

The interaction between two organisms of different species living closely together in which at least one benefits.

MUTUALISM

Both organisms benefit from each other. Organisms in a mutualistic relationship often provide each other with food and/or protection.

COMMENSALISM

One organism is benefitted while the other is unaffected. The one benefited is called a COMMENSAL, while the unaffected is the HOST.

PARASITISM

One organism benefits, while the other is harmed. The organism that is harmed is called HOST, organism that does the harm is called PARASITE.

ECTOPARASITE

Parasites found on the body surface of its host.

ENDOPARASITE

Parasites that live inside their host.

ECOLOGICAL RELATIONSHIP

The interaction among species categorized as Mutualism, Commensalism, Parasitism, Predation, and Competition.

ORDER

All living things are made up of one or more cells. Living things are highly organized and coordinated structures.

REPRODUCTION

The process of producing offspring, where living organisms are able to reproduce by duplicating their DNA and forming new cells.

SEXUAL REPRODUCTION

An organism combines the genetic information from each of its parents and is genetically unique.

ASEXUAL REPRODUCTION

One parent copies itself to form a genetically identical offspring.

SELF-POLLINATION

Happens when the pollen lands on the stigma of the flower coming from the same plant.

CROSS-POLLINATION

Occurs when the pollen lands on the stigma of a flower coming from a different plant.

GROWTH

Physical changes and quantitative qualities in organisms.

DEVELOPMENT

Growth in terms of function and capabilities, involving qualitative qualities.

SENSITIVITY OR RESPONSE

Organisms tend to respond and cope with various external factors or different environmental stresses.

HOMEOSTASIS

Organisms are able to regulate their internal environment to maintain appropriate conditions within the body.

EVOLUTIONARY ADAPTATION

Organisms have the ability to adapt and interact with their surroundings in order to survive and reproduce.

ADAPTATION

Temporary change in behavior due to environmental stress.

EVOLUTION

Permanent change in the biological structure resulting from continuous adaptation.

ENERGY UTILIZATION

Living organisms have the ability to consume and convert energy from sun and food for various purposes.

THEORY OF NATURAL SELECTION

Proposed by Charles Darwin, explaining the process of evolution.

LEVELS OF BIOLOGICAL ORGANIZATION

The hierarchy of biological structures ranging from cells to ecosystems.