Introduction to Biology

What is biology? Biology - the science of life Bio- = life -logy = the study of There is a lot of living stuff… Too many for one person to be an expert in everything Biology is broken down into many branches so scientists can specialize

Branches of Biology Botany – the study of plants Zoology – the study of animals Anatomy – the study of structures of living things Physiology – the study of the functions of living things Taxonomy – the study of classification of living things Cytology – the study of cells

Characteristics of Living Things How do you determine if something is living? Is a crystal garden alive? Is a wooden table living? Characteristics of Life Video There are seven (7) criteria that must be met for something to be classified as ‘living’

Properties of Life Cellular Organization All living things must have at least one cell Cell – a highly organized, tiny structure that can perform all life processes We will study cells more in depth later…

Properties of Life Homeostasis Homeostasis – maintaining a constant internal state in a changing environment What happens when you go for a run? What do cold-blooded animals do to keep their body temperature stable? A stable internal environment is important in order to function properly

Properties of Life Metabolism Metabolism – the sum of all chemical processes that occur in an organism Chemical processes are used in order to obtain energy Almost all energy used by living things comes from sunlight What do I mean by this?? Obviously humans don’t use photosynthesis…

Properties of Life Responsiveness Responding to the outside environment Examples: 1. Plants bending toward light 2. Turning towards a loud, sudden noise 3. Putting on a hat in winter

Properties of Life Reproduction Reproduction – producing offspring Essential…because nothing lives forever (except vampires)

Properties of Life Heredity Heredity – the passing of genetic information from parent to offspring Why children tend to look like their parents Inherited traits change over generations (evolution) More on this later

Properties of Life Growth Everything grows, even single-celled organisms Galapagos tortoise: one of the longest lived species in the animal kingdom Harriet – about 170 years old

Solving Real-World Problems Biologists are working to solve today’s problems, such as: Preserving our environment Improving the food supply Understanding the human genome Fighting disease

Solving Real-World Problems Preserving our environment Expert: conservation biologists Exploring ways to achieve a balance between people’s growing need for land and the need to preserve the environment

Solving Real-World Problems Improving the food supply Expert: genetic engineer Genetic engineering of crop plants has made some plants resistant to herbicides Or poisonous to insect pests Or even more nutritious!

Solving Real-World Problems Understanding the human genome Expert: geneticist Genome: the complete genetic material contained in an individual Only government program to be finished before the deadline and under budget!!!

Solving Real-World Problems Fighting disease Expert: virologist, doctors, lots of people AIDS – fatal disease caused by HIV HIV = human immunodeficiency virus A virus that attacks and destroys the human immune system New vaccines are being tested Attack 2 or more parts of the HIV virus at the same time One part may mutate Unlikely that both parts will mutate in the same virus particle There is finally hope of a successful vaccine to control the outbreak of AIDS 2yo 'cured' of HIV Another one

Scientific Method Collecting Observations Asking Questions Hypothesizing and Making Predictions Confirming Predictions Drawing conclusions

Scientific Method Observation – the act of noting or perceiving objects or events using the senses All scientists have a certain way of investigating the world Scientific investigations begin with observations Observations cause scientists to ask questions about their observations

Scientific Method Scientific investigations tend to have common stages These stages are called the Scientific Method There is more than one way to conduct an investigation

Scientific Investigations Hypothesis An explanation that might be true A statement that can be tested by additional observations or experimentation Prediction The expected outcome of a test This assumes that the hypothesis is correct

Scientific Investigations Experiment A planned procedure to test a hypothesis Control group A group in an experiment that receives no experimental treatment Necessary for comparing the results of the experiment

Scientific Investigations Independent Variable The factor that is changed in an experiment Dependent Variable The variable that is measured in an experiment The outcome of the dependent variable depends on what is done to the independent variable

Scientific Investigations Drawing Conclusions Once data are collected and analyzed a conclusion is made Either the data supports the hypothesis or it does not There is often more than one possible reason for a result All of the factors that may affect an outcome must be considered

Constructing a Theory Theory A set of related hypotheses that have been tested and confirmed many times by many scientists A theory unites and explains a broad range of observations Theory is used by the general public to mean a guess or lack of certainty

Constructing a Theory In Science, a theory is a well-supported scientific explanation that makes useful predictions

Matter and Substances Section 3.1

The Nature of Matter Atom – smallest unit of matter that cannot be broken down by chemical means Consists of: Electrons Protons Neutrons

Nature of Matter Elements Element – pure substance made of only one kind of atom Elements differ in the number of protons their atoms contain

Nature of Matter Chemical Bonding Compound Atoms can join with other atoms to form stable substances The force that joins atoms is called a chemical bond Compound substance made of the joined atoms of two or more different elements

Nature of Matter Covalent Bonds Form when two or more atoms share electrons to form a molecule Molecule – groups of atoms held together by covalent bonds Ex) water

Nature of Matter Covalent bonds (cont) The arrangement of their electrons determines how atoms bond together An atom becomes stable when its outer electron level is full Not full: an atom will react with other atoms that can provide electrons to fill its outer shell

Nature of Matter Hydrogen bonds In a water molecule, the shared electrons are attracted more strongly by the oxygen nucleus than by the hydrogen nuclei Molecules with unequal distribution of electrical charge are called polar molecules Ex) two water molecules

Nature of Matter Ionic Bonds Ion - when an atom or molecule has gained or lost one or more electrons Ions have an electrical charge because they contain an unequal number of electrons and protons Ions of opposite charge may interact to form an ionic bond

Water and Solutions Section 3.2

Water in Living Things Many organisms release excess heat through water evaporation This ability to control temperature enables cells to maintain a constant internal temperature when the external temperature changes HOMEOSTASIS!!

Water in Living Things Cohesion An attraction between substances of the same kind Because of this, water and other liquids form thin films and drops Because water has hydrogen bonds, the attraction between water molecules causes a condition known as surface tension

Water in Living Things Adhesion Attraction between different substances Adhesion powers a process called capillary action Water molecules move upward through a narrow tube Ex) stem of a plant

Water in Living Things Solution Mixture in which one or more substances are evenly distributed in another substance

Nonpolar molecules do not dissolve in water well Polarity The polarity of water enable many substances to dissolve in water When ionic compounds are dissolved in water, the ions become surrounded by polar water molecules Result: a mixture of water molecules and ions Nonpolar molecules do not dissolve in water well

Water and Solutions Acids and Bases Compounds that form hydrogen ions when dissolved in water are called acids When an acid is added to water, the concentration of hydrogen ions in the solution is increased above that of pure water

Water and Solutions Compounds that reduce the concentration of hydrogen ions in a solution are called bases Many bases form hydroxide ions when dissolved in water

Water and Solutions The pH scale measures the concentration of hydrogen ions in a solution

Carbon Compounds Section 3.3

Building Blocks of Cells Biomolecules – parts of a cell that are made up of large, complex molecules Basic unit: carbon Can form bonds with as many as four other atoms Four types: Carbohydrates Lipids Proteins Nucleic Acids

Carbon Compounds Carbohydrates Molecules made of sugars made of carbon, hydrogen and oxygen atoms In the proportion of 1:2:1 Carbohydrates are a key source of energy Found in most foods (especially fruits, vegetables, and grains)

Carbohydrates Common sugar: glucose A monosaccharide = single sugar Two sugars can be linked to make a disaccharide = simple carbohydrate Many sugars can be linked to make a polysaccharide = complex carbohydrate

Carbohydrates Chitin – found in shells of insects Cellulose – found in the cell walls of plants Carbs are also used as an ‘identifier’ on the surface of cells

Lipids Fats, steroids, waxes Long chains of carbon and hydrogen atoms Main function: storing energy

Proteins Building blocks are amino acids Chains of amino acids folded into different shapes Different shapes = different function Structure Support Movement Transportation

Nucleic Acids Nucleic acids are chains of nucleotides Nucleotide – molecule made of three parts Sugar Base Phosphate group Examples: DNA and RNA

Nucleic Acids DNA Act as “instructions” for the processes of an organism’s life Has two strands of nucleotides that spiral around each other RNA Interacts with DNA to help decode information