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Introduction to Biology
The Scientific Study of Life
Biology• scientific study of life
• ranges from molecular to global
–microscopic to ecosystem
• includes diversity of life now & in the past
Biological Subjects• Cytology• Virology• Embryology• Anatomy• Physiology• Molecular Biology• Genetics• Botany
• Ichthyology• Microbiology• Zoology• Evolutionary
Biology• Phylogeny• Entomology• Ecology
Organization• 5 kingdoms
• Bacteria
• Protista
• Fungi
• Plantae
• Animalia
Organization• organisms are
placed into kingdoms based on their characteristics
• all organisms in a kingdom possess same characteristics
Characteristics of Animalia Kingdom
• multicellular
• eukaryotic cells
• no cell walls
• heterotrophs-consumers
Characteristics of Life• properties shared by all living things
• Cellular Organization
• Metabolism
• Homeostasis
• Growth & Reproduction
• Heredity
Cellular Organization• all living things are
composed of cells– tiny
compartments surrounded by a membrane
• some are made up of one
• others have trillions
Metabolism• all living things use
energy
• all energy originates from the sun
• plants use this energy in photosynthesis to make sugars
• we eat plants or animals that have eaten plants
• energy is transferred to us
• transfer is metabolism
Homeostasis• living things
have processes that ensure internal environment remains stable
Growth & Reproduction
• all living things must grow
• they must reproduce
Heredity• living things must have
a genetic system found in molecules of DNA (deoxyribonucleic acid)
• determines properties of organism
• genetic code is used to pass information to successive generations
• transmission of traits is heredity
Organization of Life• enormous range of life forms on the planet• can be broken into hierarchical levels of
organization• Hierarchical organization
– means all organizational levels follow a hierarchy from lower to higher
– each level builds upon level above• Top-biosphere
– all environments on Earth that support life• next level down-ecosystem
– all organisms living in a given area as well as all non-living physical aspects of environment such as water, soil, sunlight, etc
• relationship of organism to its environment is studied in the branch of biology called ecology
• below ecosystem-community– all organisms inhabiting a given ecosystem
• Population– interacting group of individuals of one species
• one individual of a species is organism
Hierarchy of Organization of Individual
• Chemical or MolecularAtomsmolecules
• Cells
basic unit of structure and function in living things
• Tissues made of cells similar in structure & function working together to perform a specific activity4 basic tissues: connective, epithelial, muscle, and nerve
• Organsmade up of tissues that work together to perform a specific activity Examples - heart, brain, skin, etc.
• Organ Systems groups of two or more tissues working together to perform a specific functionHuman body has 11 organ systems - circulatory, digestive, endocrine, excretory
• (urinary), immune (lymphatic), integumentary, muscular, nervous, reproductive, • respiratory & skeletal
• Organisms entire living things that can carry out all basic life processes
take in materials, release energy from food, release wastes, grow, respond to the environment reproduce
usually made up of organ systems, but an organism may be made up of only one cell
Study of Biology• special way of thinking• uses empirical or scientific method
–self-correcting process for asking questions & observing natures answers
• separates science from philosophy
Parts of Scientific Method
• Observations– made in the real world
• Question– leads to a question about those observations
• Hypothesis– testable assumption or prediction
• Test hypothesis – conduct research
• Reaffirm theory – reaffirm or disaffirm theory in relation to
outcome of research