The Scientific Study of Life

• Biology is the scientific study of life
• Biological systems can be categorized by their size, forming a hierarchy from the molecular to the global level
• Biology deals with all living things, from individual cells to the entire planet
• Biological research explores life at levels ranging from molecules to the biosphere
• Common Features among all Life Forms:

  • Order
  • Regulation
  • Growth and development
  • Energy processing
  • Response to the environment
  • Reproduction
  • Evolutionary adaptation (core theme of Biology)
• The cell is the lowest level in the biological hierarchy that can be considered "alive"

  <|>Life emerges at the cellular level of biological organization
• The 7 properties of life are evident at the cellular level
• Two major types of cells are prokaryotic cells and eukaryotic cells
• Prokaryotic cells:

  • Simple and lack a true nucleus or other well-defined cellular structures
• Eukaryotic cells:

  • More complex, containing organelles that help the cell divide its labor and make it more efficient
  • Contains a nucleus that houses DNA
• Living organisms have been assigned to three domains of life:

  • Bacteria: prokaryotic cells
  • Archaea: prokaryotic cells
  • Eukarya: eukaryotic cells
• Each organism interacts with its environment, everywhere and all the time

  <|>Ecosystems involve active interactions between organisms and the environment
• Ecology is the area of biology that involves the characteristics of organisms and their interactions with the environment
• Life on Earth has a well-documented history covering billions of years of change and upheaval

  <|>Evolution is biology's unifying theme with mechanisms like mutation, genetic drift, gene flow, and natural selection
• Evolutionary patterns help in producing better applications of biology in various fields like medicine, pharmacology, and agriculture
• Science provides a means of accessing information and began when people started asking questions about the world around them and using data to answer those questions

  <|>In hypothesis-driven science, scientists use the scientific method by proposing a hypothesis, making deductions leading to predictions, and testing the hypothesis to see if the predictions come true
• Deductive reasoning is used in testing hypotheses to expect a particular outcome if the hypothesis is correct
• Data refers to information collected during an experiment or observation.
• The scientific method is the process by which scientists test hypotheses to determine if they are true.
• Scientists use experiments, observations, and measurements to collect data that can be used to support or refute their ideas about how living things work.
• Induction is a type of logical argument where generalizations are made from specific observations
• Observations involve watching something happen without changing it.
• Experiments involve manipulating variables to observe changes in other factors.
• A theory is a well-substantiated explanation of some aspect of the natural world based on empirical evidence
• Law describes what happens under certain conditions without explaining why it occurs
• Experiments involve manipulating variables to see what happens.
• Measurements involve using instruments to measure changes in variables.
• Hypothesis is a statement that explains why certain events occur.
• Measurements involve using instruments to measure physical characteristics such as length, weight, temperature, etc.
• Theories explain how things work, while laws describe what happens when they do.
• Empiricism is the idea that knowledge comes only from sensory experience
• DNA is the chemical material of genes, and all cells have it
• DNA has four bases:

  • Adenine
  • Cytosine
  • Guamine
  • Thymine
• Evolution includes

  • Mutation
  • Genetic Drift
  • Gene flow
  • Natural Selection
• Studying evolution is important because it helps us understand how we are related to other species and how we can adapt to our environment. Evolution has become the unifying theme of biology
• Deductive reasoning is used in testing hypotheses. It is a logical process that involves drawing conclusions based on a set of assumptions.
• Producers extract energy and nutrients from the nonliving environment
• Consumers obtain energy and nutrients from eating other organisms
• Decomposers are consumers that obtain nutrients from dead organisms and organic wastes
• Living organisms have been assigned to one of three domains of life: bacteria, archaea and eukarya