Characteristics of Living Things What is Biology Biology

Characteristics of Living Things

What is Biology? § Biology is the study of life § A Biologist is someone who uses the scientific method to study living things

§ No single characteristic is enough to describe a living thing § Some nonliving things share one or more traits with living things

How to tell when something is living § § § § Organized (made up of cells) Grow and develop Reproduce Evolve (as a large group) Respond to Stimuli Metabolism (homeostasis) Based on universal genetic code

Organization § Organization. Living things exhibit a high level of organization, with multicellular organisms being subdivided into cells, and cells into organelles, and organelles into molecules, etc.

Not Living

Reproduction and Heredity § Reproduction and heredity. Since all cells come from existing cells, they must have some way of reproducing, whether that involves asexual (no recombination of genetic material) or sexual (recombination of genetic material).

Growth and Development § Growth and development process. Even single -celled organisms grow. When first formed by cell division, they are small, and must grow and develop into mature cells.

Energy Acquisition and Release § Energy acquisition and release. One view of life is that it is a struggle to acquire energy (from sunlight, inorganic chemicals, or another organism), and release it. Energy is essential in maintaining metabolism and performing life processes.

Interactions § Interactions. Living things interact with their environment as well as each other. Organisms obtain raw materials and energy from the environment or another organism.

Response to Stimuli § Detection and response to stimuli from their surrounding environment (both internal and external).

§ The level of the sugar glucose in your blood is an example of an internal stimulus. If this level gets low your body responds by making you feel hungry.

Homeostasis § Homeostasis, or balance, is the maintenance of a constant (yet also dynamic) internal environment in terms of temperature, p. H, water concentrations, etc.

Evolution by means of Adaptation § Adaptation. Living things are suited to their mode of existence. Charles Darwin began the recognition of the marvelous adaptations all life has that allow those organisms to exist in their environment. § Note: Individuals do not adapt during their lifetime. Populations adapt over generations.

§ This is just an image I found to give you some perspective on the things around you. § We will discuss each of these levels of organization in detail this semester.

Jump In! § On the back of your notes draw an example of a living thing. Be sure to list: § § § how it reproduces how it communicates with other organisms how it senses stimuli from the environment how you think it maintains homeostasis how this particular organism has changed over time or will possibly change in the future.