BIO100 Flashcards - The Properties of Life

Overview of Biology: Organization and the Diversity of Life - (The Properties of Life)

Organisms

Are highly organized structures that consist of one or more cells. Inside each cell, atoms make up molecules. These, in turn, make up cell components or organelles.

Multicellular Organisms

Consist of millions of individual cells, have an advantage over single-celled organisms in that their cells can be specialized to perform specific functions.

Sensitivity or Response to the Environment

Organisms respond to diverse stimuli. For example, plants can bend toward a source of light or respond to touch. Even tiny bacteria can move toward or away from chemicals (a process called chemotaxis) or light (phototaxis). 

Movement toward a stimulus is considered a positive response, while movement away from a stimulus is considered a negative response.

Sensitivity or Response to the Environment

Reproduction

Single-celled organisms reproduce by first duplicating their DNA, which is the genetic material, and then dividing it equally as the cell prepares to divide to form two new cells. Many multicellular organisms (those made up of more than one cell) produce specialized reproductive cells that will form new individuals. 

Adaptation

All living organisms exhibit a “fit” to their environment. Biologists refer to this fit as adaptation and it is a consequence of evolution by natural selection, which operates in every lineage of reproducing organisms.

Examples of adaptations are diverse and unique, from heat-resistant Archaea that live in boiling hot springs to the tongue length of a nectar-feeding moth that matches the size of the flower from which it feeds.

Adaptation

Growth and Development

Organisms grow and develop according to specific instructions coded for by their genes. These genes provide instructions that will direct cellular growth and development, ensuring that a species’ young will grow up to exhibit many of the same characteristics as its parents.

Regulation 

Even the smallest organisms are complex and require multiple regulatory mechanisms to coordinate internal functions, such as the transport of nutrients, response to stimuli, and coping with environmental stresses.

For example, organ systems such as the digestive or circulatory systems perform specific functions like:

• carrying oxygen throughout the body

• removing wastes

• delivering nutrients to every cell

• cooling the body

Regulation

Homeostasis

To function properly, cells require appropriate conditions such as:

• proper temperature

• pH

• concentrations of diverse chemicals

These conditions may, however, change from one moment to the next. Organisms are able to maintain internal conditions within a narrow range almost constantly, despite environmental changes, through a process called homeostasis or “steady state”—the ability of an organism to maintain constant internal conditions. For example, many organisms regulate their body temperature in a process known as thermoregulation.

Energy Processing

All organisms, such as the California condor, use a source of energy for their metabolic activities. Some organisms capture energy from the sun and convert it into chemical energy in food; others use chemical energy from molecules they take in.

Evolution

The diversity of life on Earth is a result of mutations, or random changes in hereditary material over time. These mutations allow the possibility for organisms to adapt to a changing environment. 

An organism that evolves characteristics fit for the environment will have greater reproductive success, subject to the forces of natural selection.