Characteristics of Living Things Life Science Biology

 When you see either words written in yellow ink or the symbol, write down the definition from the slide.

Objectives  Be able to determine whether something is a living thing or a non-living thing.  Learn and understand the 6 main characteristics of living things.

All living things:  Have a cellular organization.  Contain similar chemicals.  Use energy.  Respond to the environment.  Grow and develop.  Reproduce.

 Organism-a living thing; anything that can carry out life processes independently.

First Characteristic of Living Things  The first characteristic of living things is that they are all composed of cells.  Cells are the itsy bitsy puzzle pieces that make up all living things.  They can be unicellular (one cell) or multicellular (many cells).

Second Characteristic of Living Things  Chemicals of Life - Cells contain: Chemicals  Carbohydrates – main energy source  Proteins and Lipids (fats, cholesterols) – building materials for cells  Nucleotides – builds genetic materials (DNA)  All these contain carbon.

Third Characteristic of Living Things  The third characteristic of living things is all living things use energy. Animals and humans eat food to obtain their energy. Plants however use the sunlight to obtain their energy.

Energy  All organisms use energy to undergo life processes.  Energy is transferred.

Fourth Characteristic of Living Things  The fourth characteristic of living things is maintenance of internal environment

homeostasis  Homeostasis is the process of an organism maintaining the inside of its body.  As the environment changes, the organism’s body makes changes in order to keep its body’s health in balance.

 When we are sick, we have not maintained our homeostasis.  Eating the right foods and staying clean are parts of this maintaining process.

Plants keep homeostasis through Tropism  Tropism is the way plants respond to stimuli.  Positive – Moves/grows to the stimuli.  Negative – Moves/grows away from the stimuli.  Plants respond to the stimuli of:  Gravity – Roots grow down.  Moisture – Roots grow towards moisture.  Light – Leaves and stems grow toward the light.

Fifth Characteristic of Living Things  The fifth characteristic of living things is that all living things grow and develop. Cell growth can include increasing cell size or the number of cells.

 Development refers to the series of changes that produces a more complex organism.  Growth is an increase in size.

Sixth Characteristic of Living Things  The sixth characteristic of living things is reproduction. Organisms produce offspring having similar characteristics.

Reproduction is sexual and/or asexual.  Sexual reproduction - reproduction with two parents which produces offspring that share traits from both parents.  Asexual reproduction - reproduction with only parent which produces offspring identical to itself.

DNA  Many organisms pass copies of their DNA to their offspring when they reproduce.

Living or Non-living and Why? Living Non-Living

Six Characteristics of Living Things 1.Cells 2.Chemicals of Life 3.Uses energy 4.Homeostasis/responds to environment 5.Growth and Development 6.Reproduction

Homework  To reinforce what has been discussed.  To increase understanding of the characteristics of living things.  Answer Question 1 on p 40 in the text. Write the questions as well as the answers.

Question:  A. List the 6 Characteristics of Living Things.  B. A bird sitting in a tree flies away as you walk by. Which of life’s characteristics explains the bird’s behavior.  C. Explain why a tree, which does not move away, is considered a living thing.