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