Introduction to biology

Introduction to biology

Biology • Bios-: greek for life • -logy: study of • A biologist uses the scientific method to study living things • Biology is the study of life • Zoology • Botany • Microbiology • Ecology • Marine Biology • Genetics • Cell biology • Anatomy and physiology • Paleontology

So….What makes something “living”? • Made up of cells • Reproduce • Genetic code • Growth and development • Obtain and use materials (resources) and energy • Respond to their environment • Maintain a stable internal environment • As a group, they change over time

Made Up of Cells • Cell • Collection of living matter enclosed by a barrier • Smallest structural unit of all living things • Prokaryotic cells • Cell without a nucleus, DNA is in cytoplasm • Eukaryotic Cells • Cell with a nucleus that contains the genetic material (DNA) • Unicellular • “uni-” means one • Organism that is made of one cell • Example: bacteria • Prokaryotic cells • Multi-cellular • “multi-” means many • Contain hundreds, thousands, even trillions of cells • Many cells work together to make the living organism function • Cells vary in size, shape and function • Example: plants and animals

Ability to Reproduce • Asexual reproduction • Organism has single parent • Genetically identical to parent • Splits in half • Sexual reproduction • Cells from two different parents unite to form new organism • Increases genetic variety and survival of species

Based on a Genetic Code • DNA nucleic acid that carries all the information about the organism • All living organisms have DNA, the “blue prints” of life

Growth and Development • Growth means increase in size, such as certain bacteria • Development refers to cells dividing to • Includes periods of rapid growth and dramatic change • Sometimes different stages (think caterpillar) • During development, cells multiply and are assigned specific functions and roles within the multi-cellular organism…DIFFERENTIATION

Obtain and Use materials and Energy • Obtain energy by taking in resources • Plants-sunlight • Lizard-insects • Metabolism • Combination of chemical reactions through which an organism builds up or breaks down materials to carry out life processes

Respond to their Environment • Stimulus • A signal to which an organism responds • External Stimuli • From environment outside organism • Example- water in soil stimulates germination • Internal Stimuli • Comes from inside an organisms body • Low sugar levels in blood will stimulate you to feel hungry

Maintain a Stable internal environment • Homeostasis • When organisms maintain a stable internal environment that is different from the external environment • Examples: shivering and sweating

As a group, they change over time • Evolution • Process of change • When a group of organisms change over time • Could occur over hundreds or millions of years • Adaptation • An inherited trait that’s helps an organisms ability to survive and reproduce in a particular environment • Over a short period of time • Natural selection • The most beneficial traits for a specific group of organisms is passed on • Organisms that have that specific trait will live longer and produce more offspring than those who do not have it • The mechanism by which evolution occurs

Levels of Organization • Molecular • DNA/RNA and other molecules • Cellular • Different cells • Groups of Cells • (cellstissuesorgansorgansystemsorganism) • Organism • A single species • Population • A group of the same species • Community • Many different groups of species and how they interact with each other in a specific area • Ecosystem • All the living and nonliving interactions in an area • Biosphere • How all the different parts (biomes) of Earth come together • Bio- means life • Sphere- earth • Life is found on land, in air, and in water • “living Earth”

Life’s Diversity of Species • Plants and animals…is there only one type? • Species • A distinct life form • Biologists have identified more than one million species • There are various estimates to the actual amount • New species are discovered daily • 5000 sp. of bacteria, 8600 sp. of birds, 30,000 sp. of fishes, 100,000 sp. of fungi, 280,000 sp. of plants and 1 million different species of…. • INSECTS

Domains • Broadest category of classification • Three main domains • Domain Archea: • unicellular prokary. That live in extreme environments (very hot or very cold, extremely acidic or basic)) • Domain Bacteria: All other unicellular prokary. • Domain Eukarya: Organism made up of eukary. Cells • Includes 4 kingdoms: Protists, Fungi, Plants, Animals

Classification • How do we organize all these species? • We categorize all the different species in to broader categories • From broadest to most specific: • Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species (Linnaean System of Classification) • Binomial nomenclature • BREAK UP THE WORD… • BI-TWO, NOMIAL-NAME, NOMENCLATURE-NAMING SYSTEM • This is how we identify a species • The African lion is called Pantheraleo • What’s the genus? • Panthera • What is the species? • Pantheraleo(you say both genus and species)

Tools of Biology Technology continually changes the way biologists work.

Imaging technologies provide new views of life. stoma • A microscope provides an enlarged image of an object. • light microscopes (LM)

Imaging technologies provide new views of life. stoma • A microscope provides an enlarged image of an object. • light microscopes (LM) • scanning electron microscopes (SEM)

Imaging technologies provide new views of life. stoma • A microscope provides an enlarged image of an object. • transmission electron microscopes (TEM) • light microscopes (LM) • scanning electron microscopes (SEM)

X-ray images • Imaging technology is used in medicine.

Imaging technology is used in medicine. • X-ray images • magnetic resonance imaging (MRI)

Imaging technology is used in medicine. • X-ray images • functional MRI (fMRI) • magnetic resonance imaging (MRI)

Complex systems are modeled on computers. Normal heartbeat • Computer models are used to study systems that cannot be studied directly. • heart attacks • effect of medicines on the human body • movement of water molecules into and out of a cell • spread of a disease through a population Heart attack • Computer models are used when experiments are not safe, ethical, or practical.

The tools of molecular genetics give rise to new biological studies. • A gene is a segment of DNA that stores genetic information.

Through our understanding of DNA, we can study genetics on a molecular level. • molecular genetics • genomics

SCIENTIFIC METHOD Review

Scientific Method • Organized problem solving • Not a single method

Steps of the Scientific Method • Define the Problem • Collect Information About the Problem • Form a Hypothesis • Experiment • Collect Results • Conclusion • Repeat

Step 1. Problem • What are to trying to find out? - Usually based on observations - stated as a question Example: I notice that on warm nights crickets seem to chirp more often Problem = Does temperature affect the rate of cricket chirps?

Step 2. Collect Information About the Problem • Information can be gathered from: - your own observations - published research textbooks, articles, internet etc…

Step 3. Form a Hypothesis • A possible solution to your problem • Must make a prediction • Must be possible to be disproved - UFOs exist is not a scientific hypothesis because it is impossible to disprove

Formal Hypothesis • A formal hypothesis used in an experiment should be stated in If…Then form. - It relates directly to the experiment to be conducted and explains the expected outcome -If I do this…..then that will happen. Example: If I raise the temperature I keep crickets in, then they will chirp more.

Step 4. Test Your Hypothesis-Experiment • Experiment must be controlled - tests only one thing at a time • A controlled experiment compares a control group with an experimental group • The control group provides a normal standard against which the biologist can compare results of the experimental group. • The experimental group is identical to the control group except for the one factor being tested - the variable being tested is the independent variable

Experimental Design • Needs to be repeatable • Should test a large sample • Should be without bias

Variables • Variable = anything that can change in an experiment • Controlled variables = What do I keep the same? • Independent variables = What do I change? akaManipulated variables • Dependent variables = What do I measure? aka Responding variables

Cricket Experiment Control Group Experimental Group 20 crickets grown in a 10 gallon aquarium 12 hours of light/day Fed 5 g Acme Cricket Food Kept at 25°C 20 crickets grown in a 10gallon aquarium 12 hours of light/day Fed 5 g Acme Cricket Food Kept at 30°C

Step 5 Data and Results Data = observations or measurements - Quantitative = number data 10 chirps/minute - Qualitative = observations color changed to orange Results = Processed data – makes the meaning of the data more clear. Allows you to see trends or patterns. Calculate an average, graph of data etc..

Graphing Your Data • Independent Variable- the factor that is changed before the experiment begins. It goes on the x-axis. Sometimes called manipulated • Dependent Variable- the factor that you ran the experiment to measure, sometimes called results. It goes on the y-axis. Sometimes called responding

Sample Graph Dependent Variable: on the Y Axis Independent Variable on the X Axis

Conclusions • Was your hypothesis correct? - do the results support your hypothesis • What are possible sources of error? • What next? – What question could you study next? • Why is this important?

Repeat Your Work/Publish • Repeat experiment to confirm your results. • When scientists have completed their work, they publish their results - this informs other scientists of their findings

Theory • A hypothesis that has been tested repeatedly and shown to be correct becomes a theory • Theories can explain current observations and predicts new observations • A theory is as close to certainty as you get in science

Vocabulary to Know and Love HYPOTHESIS EXPERIMENTAL GROUP CONTROL GROUP VARIABLE CONTROLLED VARIABLES INDEPENDENT/MANIPULATED VARIABLE DEPENDENT/RESPONDING VARIABLE DATA QUANTITATIVE DATA QUALITATIVE DATA RESULTS THEORY

Introduction to biology