What is Life? Ms. Levasseur Biology

What Characteristics Do All Living Things Share? Matter – the stuff everything is made of What is the difference between living matter and nonliving matter? No one characteristic is enough to describe a living thing

Living things are made of Cells Cells are the basic unit of life Each life form begins from one cell The cell divides many times Cells differentiate Cells organize to form the final organism Each cell type has a specific job Eye cells, heart cells, lung cells, blood cells, bone cells, liver cells, etc. Cells contain DNA – the universal genetic code

Living Things Obtain and Use Energy The sum of the chemical energy they use is called metabolism Autotrophs - use energy from the sun to make their own energy Heterotrophs - must ingest food to make energy

Living Things Maintain Homeostasis Homeostasis - stable internal conditions which must be maintained in order to remain alive Some of these conditions include temperature, water content, and heartbeat A certain level of energy must be kept within the body at all times which is why animals must ingest food on a regular basis Energy flows through systems but nutrients cycle

Living Things Grow and Develop Cells divide to form new, identical cells More cells = bigger organism Differentiation happens when cells mutate into other types of cells, making a more complex organism When organisms grow, change, and become more complex it is called development Single-celled organisms do grow as well, but they will only become slightly larger – this is nearly immeasurable

Living Things Reproduce They must reproduce in order to continue the species Two types of reproduction Sexual - combining genetic information Some characteristics from mother, some from father Asexual - splitting into two organisms The new organism is an exact copy of the first Sometimes, not every member of a species is able to reproduce as long as others are able to it will not threaten the species Mules are a bizarre anomaly