Characteristics of Living Things What does it mean to be alive?

The Big Ideas… Made of Cells Reproduce (sexually or asexually)

Living things are made of units called cells The cell is the smallest part of an organism that is considered alive. Organisms can be unicellular (one cell) or multicellular (many cells)

Living things reproduce All living organisms come from other living things. Sexual reproduction – two cells from different parents. Asexual reproduction – Offspring is created from a single parent.

The Big Ideas… Made of Cells Reproduce (sexually or asexually) Have DNA (genetic information) Grow & Develop

Living things have a universal genetic code (DNA) Directions for inherited traits are included in an organisms DNA Living things make copies of themselves; to do so they pass on genes. All organisms have the same basic DNA structure.

Living things grow and develop Some organisms increase in size (unicellular). Some organisms start as a single cell that grows, divides into two that stay connected and grows again (multicellular).

The Big Ideas… Made of Cells Reproduce (sexually or asexually) Have DNA (genetic information) Grow & Develop Need/Use Energy (metabolism) Respond to Environment

Living things need and use materials for energy (nutrient source) Nutrient source allows for chemical reactions that take place in cells. Materials come from surrounding environment. Metabolism is the combination of all the chemical processes in an organism that build up or break down materials.

Living things respond to their environment Reaction to immediate changes or needs (stimulus) Light, temperature, other organisms, hunger

The Big Ideas… Made of Cells Reproduce (sexually or asexually) Have DNA (genetic information) Grow & Develop Need/Use Energy (metabolism) Respond to Environment Maintain Homeostasis (constant internal environment) Change Over Time (evolve)

Living things maintain an internal balance External conditions may change dramatically, but most organisms must keep internal conditions relatively steady. Called homeostasis Connects with responding to our environment.

Adaptations are beneficial inherited traits that are passed to future generations. Evolution can occur through natural selection of adaptations. The genetic makeup of a population changes. Evolution is the change in living things over time

The Big Ideas… Made of Cells Reproduce (sexually or asexually) Have DNA (genetic information) Grow & Develop Need/Use Energy (metabolism) Respond to Environment Maintain Homeostasis (constant internal environment) Change Over Time (evolve) Form Systems & Have Systems (related parts) Structure & Function are Related

All levels of life have systems of related parts A cell is a system of chemicals and processes. A body system includes organs that interact. An ecosystem includes living and nonliving things that interact.

Structure determines function. Cells have a different structures and functions in complex organisms. (specialization) Different species have different anatomical structures with different functions.

…and now for Marty’s story.