ch1 the science of bio

• Biology is the science concerned with the study of life on earth
• Biologists ask questions such as: what is life? How does a single cell develop into an organism? How does the human mind work? How do different forms of life interact?
• Biology is a quest, an ongoing inquiry about the nature of life
• Life is recognized by what living things do; It is a characteristic that distinguishes physical entities that have biological processes (a tree or a dog), from those that do not (a rock or a car)
• Biology unifies much of natural science
• Living systems are the most complex chemical systems on Earth
• Life is constrained by the properties of chemistry and physics
• Biology is the study of living things—the science of life
• All living organisms consist of one or more cells (the cell theory)
• All living organisms are complex and highly ordered
• All living organisms respond to diverse stimuli from their surrounding environments
• All living organisms grow and reproduce
• All living organisms use energy to perform work
• All living organisms maintain relatively constant internal conditions regardless of the surrounding environment
• All living organisms interact with other organisms and with the environment
• Living systems show hierarchical organization at the cellular, organismal, populational, ecosystem, and biosphere levels
• The interactions occurring at lower levels can produce novel properties known as emergent properties
• Science aims to understand the natural world through observation and reasoning
• Science uses both deductive and inductive reasoning
• Scientists use a systematic approach involving observation, hypothesis formation, prediction, experimentation, and conclusion to gain understanding of the natural world
• A hypothesis is a possible explanation for an observation and must be tested to determine its validity
• Experiments are used to test hypotheses and must be carefully designed to test only one variable at a time
• Hypotheses should make predictions that can be tested through experimentation
• A theory in science is a body of interconnected concepts supported by experimental evidence and scientific reasoning
• Biologists construct models in various ways to explain living systems and suggest experiments to test how components work together
• In single-celled organisms, substances can easily enter the cell due to a short distance to be crossed
• Multicellular organisms have a larger distance for substances to enter due to a higher surface area to volume ratio
• Multicellular organisms require specialised exchange surfaces for efficient gas exchange of carbon dioxide and oxygen