how do we define life?
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How do we define life?. Properties of Living Things Are organized, and are made of one or more cells ( Cellular Organization ) Maintain stable internal conditions ( Homeostasis ) Are capable of Reproduction Exhibit Growth and development Respond to their environment (Responsiveness). - PowerPoint PPT PresentationTRANSCRIPT
How do we define life?
Properties of Living Things
• Are organized, and are made of one or more cells (Cellular Organization)
• Maintain stable internal conditions (Homeostasis)
•Are capable of Reproduction
•Exhibit Growth and development
•Respond to their environment(Responsiveness)
Properties of living things (continued)
• Pass traits to offspring (Heredity)
• Use energy. Metabolism is the sum of all chemical reactions carried out in an organism.
Stimulus or response?• The bell rings at the end of a class period• Your dog runs into the kitchen when you
open a can• A paramecium backs up and moves away
when it encounters an obstacle. • A plant grows toward the window• A baby hears a loud noise• You pull your hand away after touching the
hot oven
Examples
• Hummingbirds feed almost constantly to supply energy to their racing wings and hearts.
• Metabolism, homeostasis
• A butterfly emerges from a cocoon.
• Growth and Development
A bacterium divides into new cells every 15 minutes
• Reproduction
• An elephant's large ears allow the blood in the ears to be cooled by as much as 10 degrees.
• Homeostasis, responsiveness
• A pill bug rolls into a ball when touched.
• Responsiveness
• Earthworms are made of specialized cells, such as digestive cells, muscle cells, skin cells, etc.
• Cellular Organization
•A female frog lays many eggs at a time
• Reproduction
• A toad burrows in the mud during hot weather to avoid water loss
• Homeostasis
• Responsiveness
•An amoeba is composed of a single cell
•Cellular Organization
A child inherits cystic fibrosis from her parents
• Heredity
Mitochondria in a cell release energy from sugars
• Metabolism, cellular organization, homeostasis
Branches of Biology• Biochemistry: chemistry of
life
• Ecology: how organisms interact with each other and their environment
• Cell biology: life on the cellular level
• Genetics: how organisms pass traits to their offspring
• Evolution: changes in organisms over time
• Microbiology: microscopic organisms
• Botany: plants
• Zoology: animals