Fundamentals of Biology

• Biology is the scientific study of life
• Around 8.7 million species, excluding bacteria, have been identified

Diversity and Characteristics of Life

• Living things share the same chemical elements as nonliving things
• Living things obey the same physical and chemical laws

Defining Life

• Life is organized, with the cell being the basic unit
• Living things require materials and energy
• Living things maintain homeostasis
• Living things respond to stimuli
• Living things reproduce and develop
• Living things have adaptations

Levels of Biological Organization

• Atoms are the basic unit of matter, composed of electrons, protons, and neutrons
• Molecules are unions of two or more atoms of the same or different elements
• Cells are the structural and functional units of all living things
• Tissue is a group of cells with a common structure and function
• Organs are composed of tissues functioning together for a specific task
• Organ systems are composed of several organs working together
• An organism is an individual with complex organ systems
• A species is a group of similar, interbreeding organisms
• Populations consist of several organisms of the same kind in a specific area
• Communities are interacting populations in a particular area
• The ecosystem is a community plus the environment
• The biosphere includes regions of the Earth's crust, waters, and atmosphere inhabited by living things

Energy and Nutrients

• Living things require materials and energy for building blocks and energy
• Energy is the ability to do work
• Energy is required to maintain the organization of the cell and conduct life-sustaining processes
• Metabolism includes all chemical reactions in a cell
• The sun provides energy for life on Earth
• Plants and algae capture solar energy through photosynthesis
• Photosynthesis converts solar energy into carbohydrates

Ecosystems

• Ecosystems are characterized by chemical cycling and energy flow
• Chemicals are not used up when organisms die
• Chemicals move from one population to another in a food chain, from producers to consumers
• Inorganic molecules return to producers through decomposition
• The sun's energy flows through plants and the food chain when one population feeds on the other
• A constant input of solar energy is vital

Homeostasis

• Homeostasis maintains a balanced internal environment
• Feedback systems monitor internal conditions and make adjustments without conscious effort
• The nervous and endocrine systems are important to maintain homeostasis

Response to Stimuli

• Living things interact with the environment and respond to changes
• The ability to respond often produces movement
  • Unicellular organisms move using microscopic hairs or by moving toward or away from chemicals or light
  • Paramecium are an example, moving towards warm, acidic water
  • Multicellular organisms exhibit responses such as leaves turning toward the sun or monarch butterflies migrating south

Reproduction and Genetics

• Life comes from life
• All living organisms must reproduce to maintain a population
• Reproduction varies among different organisms
• Organisms pass on their genetic information (genes) to the next generation
• Genes determine the characteristics of an organism
• Genes are composed of DNA, or deoxyribonucleic acid

Reproduction: Asexual vs Sexual

• Asexual reproduction involves bacteria, protists, and other unicellular organisms
• Sexual reproduction occurs in multicellular organisms
• Genes contain information on how organisms are to be ordered

Adaptation and Evolution

• Adaptation is any modification that improves an organism's ability to function
• Penguins in Antarctica have stubby, flattened wings for swimming and extra fat (blubber) for warmth
• Diversity of life results from organisms adapting to changing environments
• Evolution is the change in a population of organisms over time, allowing them to become better suited to the environment

Evolution and Classification

• The theory of evolution explains the diversity and the unity of life
• Organisms are diverse but are made of cells with similar genetics, metabolic reactions, and energy requirements
• Evolution suggests living things descended from a common ancestor through "common descent with modification

Natural Selection

• Natural selection is an evolutionary mechanism for modifications (adaptations)
• The environment selects traits to be passed on
• Selective agents can be biotic or abiotic
• Individuals with favorable traits reproduce more
• Mutations fuel natural selection by introducing variations in a population
• An example is a plant species mutating to have hairy leaves

Organizing Diversity

• Taxonomy is the discipline for identifying, naming, and classifying organisms according to rules
• Systematics studies the evolutionary relationships between organisms
• Classification categories range from species to domain
• Each successive category includes more organisms than the previous one

Classification Categories

• The classification categories go from least to most inclusive
  • Species, genus, family, order, class, phylum, kingdom, and domain

Scientific Names

• Scientific names are universal, binomial, and Latin-based

Evolutionary Tree of Life

• Prokaryotes (bacteria) are structurally simple but metabolically complex
• An evolutionary tree traces life's ancestry on Earth to a common ancestor

Three Domains of classifcation

• Domain Bacteria contains unicellular prokaryotes in various environments
• Domain Archaea contains unicellular prokaryotes that live in extreme environments, organizing their DNA differently than bacteria
• Domain Eukarya includes protists, fungi, plantae, and animalia that sharee unicellular and multicellular eukaryotes withe membrane-bound nucleus

Scientific Method

• The scientific method is a standard series of steps used to gain new knowledge

Steps of the Scientific Method

• Observation involves using senses and instruments to gather information about a phenomenon or natural event
• Hypothesis formulation is a tentative explanation developed through inductive reasoning

The Experiment

• Prediction is the scientific method which uses deductive reasoning
  • If, then logic.
• Experiment is a series of procedures designed to test a hypothesis and predict an outcome
• A test group is exposed to an experimental variable
• A control group goes through all aspects of the experiment but is not exposed to the experimental variable
• Data are the results of the experiment.
• Models are organisms used to test hypothesis

Experiments (continued)

• Data is in tables or graphs with experimental results
• A graph contains x-axis (experimental variable) and y-axis (results)
• Statistics analyzes and evaluates the data in the standard error or standard deviation
• Statistical significance, probability value (P), will measure the probability that the results are due to chance or other factor
  • Less than 5% is acceptable (p<0.05)

Conclusions

• Data is analyzed and interpreted to determine whether the hypothesis is supported
• Hypothesis is rejected if the prediction does not happen
• Experiment rejects or fails to reject the hypothesis

Scientific theory

• Concepts that connect two or more supported and related hypotheses
• Supported by broad range of observations, experiments, and data

Scientific Law

• Widely accepted set of theories that are unchallenged in validity

Basic of the scientific Laws

• Cell, Homeostasis, Evolution

The scientific Processes

• First make an observation
• Come up with potential hypotheses
• Make a prediction
• Experiment and reject any hypothesis
• Confirm predictions and come to conclusion