The Nature of Life Chapter 1-3 & 1-4 The Science of Biology

Studying Life  Biology is the study of living things –“Bio” – life; “ology” – study

Studying Life Characteristics of Living Things  Nonliving things share some characteristics with living things, but not all  5 characteristics of living things –Made up of cells –Reproduce –Based on genetic code –Metabolism –Homeostasis  To be considered living, an object MUST have ALL 5 characteristics

Studying Life Characteristics of Living Things  1. Made up of cells –Smallest unit of life –Enclosed by a barrier that separates cell from surroundings-membrane –Unicellular- one celled like bacteria –Multicellular- many celled like animals and plants

Studying Life Characteristics of Living Things  2. Reproduction –All organisms can produce new organisms –Passing on of genetic information –Two types of reproduction  Sexual  Asexual

Studying Life Characteristics of Living Things Reproduction  Sexual reproduction- two cells (egg and sperm) from different parents unite to form the 1 st cell of the new organism  Humans, dogs, apes  Flowers

Studying Life Characteristics of Living Things Reproduction  Asexual reproduction- new organism has only single parent and buds off that parent –Hydra and some unusual plants

Studying Life Characteristics of Living Things  3. Based on genetic code –DNA or RNA –Changes (evolves) with time –Housed in body cells/passed in sex cells –Sexual reproduction -offspring have traits from BOTH their parents –Asexual reproduction -offspring have exact same traits as SINGLE parent

Studying Life Characteristics of Living Things  4. Metabolism - process of building up or breaking down materials –i.e. bone growth and digestion –Use energy and constant supply of materials –Produce waste products

Studying Life Characteristics of Living Things  5. Homeostasis- maintain stable internal conditions--body temp –Can respond to the environment –Plant-leans to get light –Animal  Body temperature –Blood vessel dilation –Sweating –Shivering  Blood pH –Homeostasis Animation Homeostasis AnimationHomeostasis Animation

Studying Life Levels of Organization Biosphere Ecosystem Community Population

Studying Life Levels of Organization Organism Groups of Cells Molecules Nerve cell Water DNA Which of these levels do not contain living things?

Studying Life Scientist Specialization  Biologists  Ecologists  Population biologists  Zoologists  Cellular biologists  Molecular biologists

Studying Life Scientists’ Tools  Common measurement system –Metric system or (SI)- a measurement system used worldwide by scientists based on multiples of 10  Mass-grams (g)  Volume-liters (L)  Distance-meters (m)  Temperature- Celsius ( o C)

Studying Life Scientists’ Tools  Different types of microscopes –Light microscopes-magnifies images by focusing light on them  Most commonly used  Compound light microscopes- have two lenses  Stains may be added to make objects more visible –Electron microscopes- magnifies images by focusing a beam of electrons on them

Studying Life Scientists’ Tools Microscopes –Electron microscopes  Produce magnified images by focusing beams of electrons on them  Can produce images 1000X’s more detailed than light microscopes  Two types –TEM (transmission electron microscope) –SEM (scanning electron microscope)

SEM photo What is this?

Foot of a Housefly