Characteristics of Living Things

What is an organism?  An organism is any living thing.

All living things… All living things… no matter how different no matter how different they are from each other… share a set of common share a set of common characteristics. characteristics.

All living things share six basic characteristics.  Have a cellular organization  Contain similar chemicals  Use Energy  Respond to their surroundings  Grow and Develop  Reproduce

 All organisms are made of cells. made of cells.  A Cell is the basic unit of structure and function in an organism  Organisms may be made of only one or many cells. 1. LIVING THINGS HAVE A CELLULAR ORGANIZATION.

A UNICELLULAR organism is made of one cell. is made of one cell.  This single cell is responsible for carrying out all of the functions necessary to stay alive.  Common unicellular organisms: Bacteria paramecium amoeba

MULTICELLULAR organisms are made of many different types of cells.  Cells are specialized to do certain tasks. certain tasks.  Specialized cells work together to keep you alive. together to keep you alive.

 Multicellular organisms:  Plants  Animals  Fungi

2. LIVING THINGS CONTAIN SIMILAR CHEMICALS  Water – most abundant  Carbohydrates – main energy source  Proteins and lipids – building materials of cells  Nucleic acids – DNA  Genetic material  Instructions cells need to carry out functions

3. LIVING THINGS USE ENERGY  Get energy from taking in and breaking down materials and breaking down materials  Metabolism: The combination of chemical reactions through which an organism builds up or breaks down materials.

 Energy needed to carry out activities of life or life processes. Growing Growing Responding Responding Moving Moving Plants move when growing Plants move when growing or leaning toward sun or leaning toward sun Animals move from place to place Animals move from place to place for food, protection for food, protection

4.LIVING THINGS RESPOND TO THEIR SURROUNDINGS.  Living have the ability to sense change in their environment.

Stimulus – change in an organism’s surroundings that causes it to react. Stimulus – change in an organism’s surroundings that causes it to react. Response – action that occurs as a result of a stimulus Response – action that occurs as a result of a stimulus

Examples of Stimulus/ResponseExamples of Stimulus/Response Stimulus a. Light a. Light b. Hot iron b. Hot iron c. Change of c. Change of season season Response a. Plant bends a. Plant bends toward light toward light b. Pull hand away b. Pull hand away c. Birds migrate c. Birds migrate

 Even if external environment changes, living things have the ability to maintain a stable internal environment to survive: This is called Homeostasis. This is called Homeostasis.

5. LIVING THINGS GROW AND DEVELOP  Growth– getting larger in Size You grow from You grow from 2’ to 5’. 2’ to 5’.  Development – getting More complex You learn to talk You learn to talk and walk. and walk.

Living things grow and develop within a life span or time expected to live. Living things grow and develop within a life span or time expected to live. Elephant: 70 years Elephant: 70 years Bristle-cone pine: 5500 years Bristle-cone pine: 5500 years

6. LIVING THINGS REPRODUCE  Reproduce – produce offspring that are similar to the parents.  Reproduction is necessary for species to survive over time.

 Asexual reproduction: One parent produces offspring identical to parent. Some animals: hydra Some animals: hydra Some plants, as when Some plants, as when a plant grows from a leaf rooting. a plant grows from a leaf rooting.

 Sexual reproduction:  Involves two parents and combines their genetic material to produce a new organism that differs from both parents. Most animals and most plants Most animals and most plants

Where Do Living Things Come From?  Living things arise from other living things through reproduction.-BIOGENESIS  400 years ago – People thought life could spring from non-living matter.  This mistaken idea is known as spontaneous generation.  It took hundreds of years of experiments to convince people that spontaneous generation does not occur.

Redi’s Experiment  In 1600’s Francesco Redi (Italy) helped disprove spontaneous generation.  Designed one of the first controlled experiments to prove flies do not come from decaying meat.

Redi’s Experiment

Examples  Worms came from rain.  Frogs came from mud.  Mice came from hay.

Pasteur’s Experiment  In mid 1800’s Louis Pasteur, a French chemist, conducted a controlled experiment demonstrated that bacteria arise only from existing bacteria.