Characteristics and Needs of Living Things Introductory Video (click here to play)

Spontaneous Generation Spontaneous-Generation Theory - life could spring from nonliving matter. Prior to the 1600’s people believed this was possible. Mice came from a bail of straw. Frogs came from ponds and mud. 1668 – Francisco Redi disproved Spontaneous-Generation.

Spontaneous Generation Here’s How: Belief: maggots came from rotting meat. Redi placed rotting meat into three sets of jars First set was left open Second set was tightly sealed Third set was covered with cheese cloth Set 1 Set 2 Set 3 Open Jars Tightly Sealed Jars Jars Covered with Cheese Cloth

Spontaneous Generation After a Few Days: Open Jars = maggots Flies could smell and land on the meat. Tightly Sealed Jars = NO maggots Flies couldn’t smell or land on the meat. Cheese Cloth = maggots ON TOP of jars Flies could smell the meat but not land on it. Set 1 Set 2 Set 3 Open Jars Tightly Sealed Jars Jars Covered with Cheese Cloth

Spontaneous Generation 1. What is the Problem Redi was attempting to solve? Do maggots come from rotting meat? 2. Which set of jars are the Control? Set 1 – Open Jars 3. What is the independent variable? Covering the jars. 4. What is the dependent variable? No maggots on meat.

Spontaneous Generation Conclusion: Because maggots were not found on the meat with covers Spontaneous generation does not occur! Nonliving can NOT produce living!

Characteristics of Living Things There are certain characteristics that all living organisms have: To be considered alive, an object must exhibit ALL of these characteristics! (Video – 4:52min) Living Things are Made of Cells Cells are the basic building blocks of living things. Cells come ONLY from other cells! Two types: Plant cells Animal cells

Characteristics of Living Things Living Things Perform Complex Chemical Activities All living organisms need to take in substances from their environment in order to; obtain energy, to grow and stay healthy. Metabolism = the sum total of all the chemical reactions that occur in a living thing. 3. Living Things Grow and Develop All living things become larger and more complicated as they grow. All living things have a limited life span Metabolism = Ingestion + Digestion + Respiration + Excretion

Characteristics of Living Things 4. Living Things Must Be Able to Move Movement can be external (walking, flying or swimming) but can also be internal (movement of substances throughout the body, transportation of water through a tree). 5. Living Things Reproduce All living things are dependent on reproduction for the continuation of their species. Asexual Reproduction - (single-celled organisms) Involves only one parent genetic information is identical from parent to offspring.

Characteristics of Living Things B. Sexual Reproduction – (multi-cellular organisms) Involves two parents genetic information is an equal combination of half of each parent’s genes. Asexual Reproduction Sexual Reproduction Sperm – male sex cell Genetically Identical Offspring to Parent Cell Fertilized Egg Parent Cell Egg – female sex cell

Characteristics of Living Things 6. Living Things Respond to Their Environment Signals to which an organism would react are stimuli (singular), stimulus (plural) A response is the movement, reaction or change in behavior by the organism, to the stimuli. We react to touch, light, heat, cold and sound, as do other living things. 7. Living Things Adapt to Their Environment Adaptations are traits giving an organism an advantage in a certain environment. Polar Bear – white thick fur (camouflage with snow) Whale – blubber (survival in extreme cold conditions) Giraffe – long neck (reach tops of tall trees) Peppered Moth – camouflage with tree bark

Living or Nonliving? N L N L N

Needs of Living Things Living things depend on both the living and nonliving parts of their environment for survival. Energy All living things need energy. Primary source of energy is the sun. Food and Water Food is the source of energy as well as the supplier of the raw materials needed for growth, development and repair of body parts. Organisms can only survive a few days without water but can go weeks to months without food. Cells must have a continuous supply of water to function properly – (NO water = no cell functions and life STOPS!)

Needs of Living Things 3. Oxygen Necessary for the process of respiration. Respiration: oxygen + nutrients = energy The waste products of respiration are carbon dioxide and water Plants must have carbon dioxide and water for photosynthesis to take place. Respiration: Oxygen + Glucose Energy + Water + CO2 Photosynthesis: Energy + Water + CO2 Oxygen + Glucose (Sunlight)

Needs of Living Things Living Space Competition = the struggle among living things to get the proper amount of food, water and energy. Proper Temperature Some organisms must keep their internal body temperatures constant to survive – homeostasis. Even with an ever changing outside environment internal temperatures must remain constant – Warm-blooded Organisms. People = 37°C (98.6 °F) Other organisms have the ability to adjust their body temperatures with the environment – Cold-blooded Organisms. Fish, Snakes, Turtles