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All things considered to be alive have what characteristics in common? • Make a list of reasons why you think the following organisms are considered “alive”. • Group that comes the closest wins…
8 characteristics of living things • Have cells and DNA • Reproduce • Grow and Develop • Use energy • Have a need for materials and energy • Respond to environment • Maintain internal balance • Evolve over time as a species
1. Have cells and DNA • Unicellular • Multi-cellular
1. HAVE CELLS AND DNA • Multi-cellular: cells differentiate from a single fertilized egg cell, and they just “know” to become a heart, leg etc. • Uni-cellular : one celled organism (amoeba or bacteria) • Both above have DNA ( the genetic code: which is why we look like our parents)
2. All living things reproduce • There are 2 ways in which this can be done…
2. All living things Reproduce • There are 2 types of reproduction: • Asexual : 1 parent (budding) - identical • bacteria • Sexual: 2 parents • cats • people
3. Living things grow and develop • What is the difference between the 2 words?
Growth and Development • Bacteria- grow, they just increase in size • People – develop … they increase in size and their bodily functions change over time….until they become an adult • ex) puberty…
Living things use energy to grow/develop/reproduce… or just stay alive • Where do we get energy from? • Metabolism: combination of chemical reactions through which an organism builds up and breaks down materials (will release energy) as it carries out life processes • Fast metabolism- break down • Slow metabolism – store for later
How obtain energy? • Plants: From the sun’s energy “photosynthesis” • Lion: From eating other organisms “herbivore, carnivore” • Mushroom: From the remains of dead organisms (decomposers)
6. Living things respond to stimuli • http://www.fotosearch.com/video-footage/time-lapse-flower_2.html
6. Respond to stimulus • Stimulus- signal to which an organism responds • Response-(what they do because of the signal) • Internal stimulus- ex.) sugar levels drop? …then you feel hungry • External: ex.) flower leans toward the window in a classroom
Practice Stimulus and Response • My niece kicked me in the shin and I screamed • I slammed the door and the class jumped • I turned the light on and the mouse ran under the table • I placed my hand on the hot stove and I yanked it back and yelped
7. Maintain internal balance • External: conditions may vary widely • But internal…. Should be kept constant.. This is homeostasis • Ex) temperature 98.6 F, water content, etc • Ex of how it happens? • Shivering/sweating • Thirst/feeling of fullness
8. Evolve over time :Evolution • 100,000’s of millions of years…changes can be dramatic within a species… • ex) pre-historic horse was the size of a Barbie doll horse