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Introduction to Biology. Biology for Majors. Properties of Life. All living organisms share several key characteristics: order sensitivity or response to the environment reproduction growth and development regulation homeostasis energy processing. Properties of Life: Order.
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Introduction to Biology Biology for Majors
Properties of Life All living organisms share several key characteristics: • order • sensitivity or response to the environment • reproduction • growth and development • regulation • homeostasis • energy processing
Properties of Life: Order • Organisms are highly organized
Properties of Life: Sensitivity • Organisms respond to diverse stimuli
Properties of Life: Reproduction • Organisms can reproduce, creating new life
Properties of Life: Growth • Organisms grow and develop
Properties of Life: Regulation • Organisms have regulatory mechanisms to cope with environmental stresses
Properties of Life: Homeostasis • Organisms have regulatory mechanisms to cope with environmental stresses
Properties of Life: Energy Processing • All organisms use a source of energy for their metabolic activities. • Photosynthesis • Cellular Respiriation
Organization of Matter • Atoms: the fundamental unit of matter • Atoms form molecules • Many molecules that are biologically important are macromolecules • Aggregates of macromolecules form organelles • Organelles together create a cell • DNA is an example of a molecule
Organization of Life From a single organelle to the entire biosphere, living organisms are part of a highly structured hierarchy.
Features of All Cells All cells have four components: • A plasma membrane • Cytoplasm • DNA • Ribosomes
Prokaryotic Cells • Nucleoid (no nucleus) • No membrane-bound organelles • Cell wall • Some prokaryotes have flagella or pili
Practice Question Let’s revisit the hierarchy chart for blood cells. How would this be different for a prokaryotic cell?
Eukaryotic Cells • Typically larger than a prokaryotic cell • True nucleus • meaning its DNA is surrounded by a membrane • Other membrane-bound organelles
What is Biodiversity? • Biodiversity refers to the variety of life and its processes • variety among different living organisms • the variety within populations
Phylogeny These phylogenetic trees show the relationship of the three domains of life—Bacteria, Archaea, and Eukarya
Taxonomy Taxonomy is the science of classifying organisms. Using the chart at the right, what is the scientific name for the common dog in binomial nomenclature?
Scientific Inquiry • Forming a Hypothesis – Hypotheses must be testable and falsifiable. • Experimental Design – Consider sample size and selection and how to avoid bias. • Experimental Variables – Determine the independent and dependent variables and what variables to control in the experiment. • Interpreting Results – Gather data by measuring the dependent variable then assess whether the results are statistically significant
Quick Review • What are the defining characteristics of biological life? • What are the different kinds of cells that make up different kinds of organisms? • What are the classification and organizational tools biologists use, including modern taxonomy? • Describe biology as a science. • What are the key components of scientific inquiry?