Biology: The study of LIFE

1-1: Study of Life  First living thing or ORGANISM arose 3.5 BILLION years ago  Over time organisms changed  Biology studies many various things  SIX unifying themes

Unifying Themes 1.Cell structure and function 2.Stability and homeostasis 3.Reproduction and inheritance 4.Evolution 5.Interdependence of organisms 6.Matter, energy, and organization

Group Project!  You will be assigned a group of three  You will be assigned ONE of the SIX themes of Biology  On a poster you must include:  Name of the theme  Description of the theme  THREE (3) examples of organisms demonstrating the theme  Illustration of the theme  You will present your poster with your group to the class 1.Cell structure and function 2.Stability and homeostasis 3.Reproduction and inheritance 4.Evolution 5.Interdependence of organisms 6.Matter, energy, and organization

Cell Structure and Function  CELL: basic unit of all life; HIGHLY organized  UNICELLULAR: organisms composed of just ONE cell  MULTICELLULAR: organisms composed of multiple cells  Individual cells of multicellular organisms usually undergo DIFFERENTIATION to specialize in specific function

Cell Differentiation

Stability and Homeostasis  HOMEOSTASIS: stable level of internal conditions  temperature  water content  food intake  Human?  Seal?  Tortoise?

Reproduction and Inheritance  REPRODUCTION: all organisms produce organisms like themselves  Organisms transmit hereditary information to their offspring  Hereditary information is in the form of DNA or DeoxyriboNucleic Acid

DNA  Multicellular and some unicellular organisms  enclosed in membrane  Other unicellualr organisms  DNA loop  DNA contains all instructions or GENES  All cells have the SAME DNA in them  Some cells use different genes than others

Types of Reproduction  Sexual Reproduction  hereditary information from two organisms of the same species combine  egg (female) and sperm (male) combine and begin cell division  multiple cells all with SAME EXACT copies of NEW combination of hereditary information  Asexual Reproduction  hereditary information from two different organisms not combined  Ex: Bacterium splits into two; each cell containing identical copies

Evolution  Process of populations of an organisms changing OVER TIME  Helps us understand...  variation amongst organisms in existence  relationship between alive organisms and those in the past  basis for exploring relationships amongst living organisms  why organisms look and behave as they do

Natural Selection  Process by which organisms with favorable traits have are better able to reproduce than individuals with out these characteristics

Interdependence of Organisms  ECOLOGY: study of interaction of organisms with each other and environment  ECOSYSTEMS: environmental communities  How do you interact with other organisms and your environment?

Matter, Energy, and Organization  Living things require ENERGY  Almost all energy comes from the SUN  PHOTOSYNTHESIS  plants and some unicellular organisms capture energy from sun and make it usable to other living things  What did you eat today?

How organisms get their energy  AUTOTROPHS: From the sun  make their own food  some trap sun and convert carbon dioxide and water into usable energy, sugar  most plants and some other  HETEROTROPHS: By consuming autotrophs or other heterotrophs for food  all animals, fungi, many unicellular organisms, and some plants

1-2: Characteristics of Life

Characteristics  Cells  Organized  Use energy  Keep homeostasis  Grow  Reproduce How do these organisms fulfill these requirements?

Cells  All living things are composed of cells  In multicellular organisms some cells are specialized and play a specific role

Organization  Cells are organized by their function

Energy Use  METABOLISM: the process in which living things use energy  sum of all chemical processes within an organism  Organisms require energy to...  maintain cellular and molecular organization  grow  reproduce

Homeostasis  All living things maintain stable internal conditions  Multicellular organisms usually have more than one systems to maintain homeostasis  Cold? Too hot?

Growth  Nonliving growth: accumulate more of material they are made of  Ex: crystals and icicles  Living growth: cell division and cell enlargement  CELL DIVISION: formations of TWO cells from ONE cell  DEVELOPMENT: achieved by repeated cell division and cell differentiation

Reproduction  All species have the ability to reproduce  NOT essential to the survival of an INDIVIUAL organism  ESSENTIAL to the continuation of a SPECIES  Many species have ways to combine genetic information so that the offspring are NOT identical to the parents

Living or Nonliving?

1-3: Scientific Method

Steps 1.Observe 2.Question 3.Collect Data 4.Hypothesize 5.Experiment 6.Draw Conclusion

Observe and Ask a Question

Collect Data  How?  Observe: employ one or more of the five senses  Measure: quantitative data (data that can be measured in numbers)  Sample: using a small part (sample) to represent an entire population  Organize Data  Graph, chart, table, map

Hypothesize  Once scientists have made MANY observations and collect MUCH data they suggest an explanation or HYPOTHESIS  Explains observations AND can be tested  Can be wrong but can NEVER be proven true beyond all doubt  Can revise original hypotheses or even discard

Prediction  To test a hypothesis, scientists formulate a PREDICTION which logically follows the hypothesis  PREDICTION: statement made in advanced that states the results that will be obtained from testing a hypothesis (if it is true) ***If...then...***  Hypothesis: There is a fungus spreading throughout Panama killing the Golden Frogs.  Prediction: If the Golden Frog is exposed to the fungus then it will not survive.

Experimenting  Process of testing a hypothesis or prediction by gathering data under CONTROLLED conditions  Controlled experiment  Two groups: Control Group & Experimental Group  Both groups identical except for one factor: INDEPENDENT VARIABLE  Another factor measured: DEPENDENT VARIABLE (driven by/dependent on other variable)

Golden Frogs Experiment Independent variable? Dependent variable?

Conclusion  Modeling: an explanation supported by data  Visual, verbal, or mathematical  Helps show relationships among data  Sometimes help generate new hypotheses or predictions  Chytrid fungus ultimately suffocate Golden Frogs when they are exposed to it.

 INFERENCE: conclusion based on facts not observations  often drawn from data gathered and previous knowledge  NOT directly testable  Ex: If you see smoke, you may think there is a fire even though you cannot see the fire.  THEORY: a broad and comprehensive statement of what is thought to be true  supported by considerable evidence  may tie together several related hypotheses

Hypothesis, theory, inference

Communication  Scientist share their findings and data with other scientists  publish findings in scientific journals  share findings at scientific meetings  Work of every scientist is subject to examination and verification by any other scientist  Allows scientists to build on work of others

Microscopy and Measurement

Microscope  An instrument that produces an enlarged image of an object  Used to study organisms, cells, and cell parts  Increase image made by object and show it’s details  MAGNIFICATION: the increase of an object’s apparent size  RESOLUTION: power to show an object’s details clearly

Light Microscopes  COMPOUND LIGHT MICROSCOPE (LM)  To see small organisms and cells  Specimen must be cut thin enough so that light can pass through and mounted onto glass slide  Different set magnifications

Light Microscope

Parts of LM  STAGE: supports specimen  LIGHT SOURCE: mirror, light bulb; directs light upwards, through specimen  OBJECTIVE LENS: enlarges image of object  NOSEPIECE: holds objective lens of different magnifications  OCULAR LENS: near eyepiece; magnifies image further  CONDENSER/ DIAPHRAGM: controls the amount of light projected to specimen  COARSE FOCUS: focuses object into view  FINE FOCUS: focuses fine details of object into view

Electron Microscope  At about 2000x magnification images become blurry  ELECTRON MICROSCOPE uses beam of electrons instead of light to enlarge image of specimen  Types:  Transmission Electron Microscope (TEM)  Scanning Electron Microscope (SEM) Black Walnut Tree Leaf

Transmission Electron Microscope  Transmits beam of electron though very thin slice of specimen  Magnetic lenses enlarge image and project it in screen or photographic plate  PRO: 200,000x magnification  CON: Can NOT view living things

Scanning Electron Microscope  Provides 3-D images  Specimen not sliced but coated with a fine metal spray  Electrons bounce off metal coating and projected onto fluorescent screen of photographic plate  PRO: 100,000x magnification; 3-D image  CON: Can NOT be live specimens

LM vs TEM vs SEM Mitochondria, mammalian lung Fly Head Diatom, 1000x

Measurements  SI: Système International d’Unités or International System of Measurements  SEVEN fundamental basic units that describe  length  mass  time  temp.

The power of 10...

SI Derived Units  Area: m 2  Area= length x width  m x m = m 2

That’s all for Chapter 1! You now have the answers for your first test! GOOD LUCK!