What is Life? CharacteristicsOf Living Things

Organisms Any living thing Any living thing

All Living Things: Have cellular organization Have cellular organization Contain similar chemicals Contain similar chemicals Use energy Use energy Grow and develop Grow and develop Respond to the environment Respond to the environment Reproduce Reproduce

Cellular Organization Unicellular-single celled organisms such as bacteria Unicellular-single celled organisms such as bacteria Multicellular-organisms which are composed of many cells Multicellular-organisms which are composed of many cells

Unicellular

Multicellular

Chemicals of Life Water-H2O Carbohydrates-sugars Proteins Lipids-fats Nucleic Acids-DNA

Energy Use All living things use energy for growth and cell repair Energy is used for work-for example digesting food, pumping blood and exchanging gases (breathing)

Growth and Development Growth is the process of becoming larger Growth is the process of becoming larger Development is the process of change that occurs during an organism’s life-such as healing and specialization Development is the process of change that occurs during an organism’s life-such as healing and specialization

Response to Environment Stimulus-a change in an organisms environment that causes an organism to react (such as changes in temperature, light sound, etc.) Stimulus-a change in an organisms environment that causes an organism to react (such as changes in temperature, light sound, etc.) Response-an action or change in behavior (such as flinching, shivering, a plant bending toward the light) Response-an action or change in behavior (such as flinching, shivering, a plant bending toward the light)

Reproduction Producing offspring that are similar to the parent organisms (birds lay eggs, plants make seeds, bacteria divide into two exact replicas of the original bacteria) Producing offspring that are similar to the parent organisms (birds lay eggs, plants make seeds, bacteria divide into two exact replicas of the original bacteria)

Life Comes From Life Spontaneous generation- the mistaken idea that living things arise from nonliving things Spontaneous generation- the mistaken idea that living things arise from nonliving things Francesco Redi-designed a controlled experiment to disprove spontaneous generation Francesco Redi-designed a controlled experiment to disprove spontaneous generation Louis Pasteur-designed an experiment to show that microorganisms live in the air Louis Pasteur-designed an experiment to show that microorganisms live in the air

Francesco Redi’s Experiment Redi Placed meat in jars, one was left uncovered and one was covered with cloth Redi Placed meat in jars, one was left uncovered and one was covered with cloth He left the jars out for a few days He left the jars out for a few days The jar that was left open had maggots The jar that was left open had maggots The jar that was covered didn’t have any maggots The jar that was covered didn’t have any maggots He concluded that the flies he had seen had laid eggs on the meat He concluded that the flies he had seen had laid eggs on the meat His experiment helped to disprove spontaneous generation His experiment helped to disprove spontaneous generation

Louis Pasteur’s Experiment Pasteur placed broth in two flasks which had curved necks which allowed air to enter but not bacteria in the air Pasteur placed broth in two flasks which had curved necks which allowed air to enter but not bacteria in the air He boiled one flask but not the other one He boiled one flask but not the other one The flask which had been boiled remained clear, but the other one spoiled The flask which had been boiled remained clear, but the other one spoiled His experiment showed not only that bacteria is everywhere, but also that boiling can kill most bacteria and that bacteria only form when other bacteria are present His experiment showed not only that bacteria is everywhere, but also that boiling can kill most bacteria and that bacteria only form when other bacteria are present

Energy Autotrophs-organisms, such as plants, which can make their own food Autotrophs-organisms, such as plants, which can make their own food Heterotrophs-organisms that cannot make their own food, they have to ingest food Heterotrophs-organisms that cannot make their own food, they have to ingest food

Autotrophs

Heterotrophs

Water All living things need water All living things need water Water is able to dissolve more chemicals than any other substance on earth Water is able to dissolve more chemicals than any other substance on earth Makes up 92 percent of your body weight Makes up 92 percent of your body weight

Homeostasis The maintenance of stable internal conditions despite changes in its surroundings (like sweating when your hot, shivering when your cold, or a plant which goes dormant in the winter)