Chapter 1 “The Science of Biology” The goal of science is to investigate and understand, to explain events in nature, and to use those explanations to make useful predictions.

Chapter 1 – 1 “What is Science?” Science – an organized way of using evidence to learn about the natural world Science only deals with the natural world Scientists collect and organize data looking for patterns and connections between events Scientists propose explanations that can be tested through experimentation

What is Science? Science always starts with an observation Scientists observe the natural world using all of the five senses of the body as they gather information The evidence that scientists gather from their observations is called data

Scientific Observation Observations can be classified into two types: Quantitative observations involve numbers, counting, or measuring objects (Example) How many Basenjis have destroyed the pillow? Qualitative observations involve things that cannot be easily measured like color or texture (example) One of the basenjis has a white “ring” around it’s neck

What is Science? Interpreting Evidence After a scientist gathers evidence or observes something they must be able to interpret the evidence or data This means that they need to try and understand what was observed This is usually done with an inference A logical interpretation based on prior knowledge and experience

What is Science? Explaining the Evidence Scientists form hypotheses to provide possible explanations for the natural world A Hypothesis is a possible explanation for a set of observations or an answer to a scientific question DO NOT write: an educated guess!!! In science, a hypothesis is useful only if it can be tested

Designing an Experiment State the Problem Analyze Results Form a Hypothesis Draw a Conclusion Make Predictions Publish Results Set up Experiment

Designing an Experiment Experiments are the difference between ideas and reality! Before experiments, ideas like spontaneous generation were accepted The idea that life arose from non-living matter

Controlled Experiments When you test a hypothesis in science you must design an experiment The factors that you change in the experiment are called variables Variables can be a number of things: Equipment Type of material Amount of material Temperature Light Time

Controlled Experiments A controlled experiment is when you are able to test only one variable at a time Whenever possible, this is the best type of experiment This is also called “isolating the variable” All of the other variables remain constant or controlled Manipulated variable – the variable that is deliberately changed Responding variable – the variable that changes can be observed as a response to the manipulated variable

Redi’s Experiment on Spontaneous Generation OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. PROCEDURE Uncovered jars Covered jars Controlled Variables: jars, type of meat, location, temperature, time Manipulated Variables: gauze covering that keeps flies away from meat Several days pass Responding Variable: whether maggots appear No maggots appear Maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

Section 3 “Studying Life” BIOLOGY means “the study of life” In order to be considered part of biology something must have these “characteristics of living things”: Living Things: Are made up of units called cells Are able to reproduce Are based on a universal genetic code (DNA) Are able to grow and develop Obtain and use materials and energy Respond to their environment Maintain a stable internal environment As a group, change over time

Section 3 “Studying Life” Being Made up of Cells : A cell is a collection of living matter enclosed by a barrier that separates the cell from it’s surroundings Cells can grow in response to their environment and they can be quite complex even though most cells are very small Many living things are made up of only one cell and are called unicellular meaning “single celled” When an organism is made up of many cells it is called multicellular Our bodies are multicellular, highly complex living organisms

Section 3 “Studying Life” All Living things must Reproduce : Whenever an organism creates another organism it is called reproduction There are two types of Reproduction: Sexual Reproduction is when two parents contribute a cell to create a new organism Asexual Reproduction is when one parent can create a new organism either by dividing in half or breaking off a piece of itself to contribute to a new organism

Section 3 “Studying Life” Based on a Genetic Code: When one organism produces offspring as in asexual reproduction, the offspring are genetically identical Sexual reproduction involves the genes from two parents and yields offspring that are genetically unique Any way an organism is created they are all similar in one way, the fact that they are made up by a molecule called DNA (Deoxyribonucleic Acid) DNA consists of four nitrogen bases and it is the arrangement, order, and number of these bases that code for every living organism on our planet

Section 3 “Studying Life” Living things Grow and Develop : During the life of an organism it grows and develops in it’s environment Living things Obtain and Use Materials and Energy : All living things must consume whether or not they are a plant, animal, fungus, or bacteria An organism’s metabolism is a combination of chemical reactions that break down food and materials Living things respond to their environment : A stimulus is a signal to which an organism responds like a light or a sound

Section 3 “Studying Life” Levels of Organization: Our planet is extremely diverse in population and we can organize based on a system called levels of organization The Biosphere is the part of the earth that contains all of the ecosystems An ecosystem is the community and it’s non-living surroundings A community is a population that lives in a defined area or space