Chapter 1: The Science of Life

Section 1: The World of Biology Objectives Relate the relevance of biology to a person’s daily life Describe the importance of biology in human society List the characteristics of living things Summarize the hierarchy of organization within complex multicellular organisms Distinguish between homeostasis and metabolizm and between growth, development, and reproduction

Ch. 1.1 The World of Biology Biology and You Biology is the study of life and can be used to both solve societal problems and explain aspects of our daily lives https://www.youtube.com/watch?v=VgTPg99V_JM

Ch. 1.1 The World of Biology Characteristics of Life Living things share the same 7 characteristics: Organization and cells Response to stimuli Homeostasis Metabolism Growth and development Reproduction Evolution

Ch. 1.1 The World of Biology Characteristics of Life Organization is the high degree of order within an organism’s internal and external parts and in its interactions with the living world A cell is the smallest unit of an organism that can perform all life’s processes

Ch. 1.1 The World of Biology Unicellular vs. Multicellular Some organisms, such as bacteria, are made up of a single cell and are called unicellular organisms Some organisms are made up of many cells and are called multicellular organisms

Ch. 1.1 The World of Biology Organization and Cells Multicellular organisms are made up of many cells and show a hierarchy of organization going from the organism to the atom

Ch. 1.1 The World of Biology Characteristics of Life Response to Stimuli A living organism can respond to a stimulus—a physical or chemical change in the internal or external environment

Ch. 1.1 The World of Biology Characteristics of Life Response to Stimuli https://www.youtube.com/watch?v=TTyuisUCcvo https://www.youtube.com/watch?v=vtLzxEYSe30

Ch. 1.1 The World of Biology Characteristics of Life Homeostasis All living things have mechanisms that allow them to maintain stable internal conditions. Homeostasis is the maintenance of a stable level of internal conditions even though environmental conditions are constantly changing.

Homeostasis https://www.youtube.com/watch?v=d2YWonZsh_M

Homeostasis

Ch. 1.1 The World of Biology Characteristics of Life Metabolism Metabolism is the sum of all the chemical reactions that take in and transform energy and materials from the environment.

Ch. 1.1 The World of Biology Characteristics of Life Growth and Development The growth of living things results from the division and enlargement of cells Development is the process by which an organism becomes a mature adult

Ch. 1.1 The World of Biology Characteristics of Life Reproduction Living organisms pass on hereditary information from parents to offspring, also called reproduction

Ch. 1.1 The World of Biology Characteristics of Life Change through time Populations of living organisms evolve or change through time

Ch. 1.1 The World of Biology Living vs. Non-Living

Ch. 1.2 Themes In Biology Objectives Identify three important themes that help explain the living world Explain how life can be diverse, yet unified Describe how living organisms are interdependent Summarize why evolution is an important theme in biology

Ch. 1.2 Themes In Biology Diversity and Unity of Life Life is so diverse, or full of variety. Yet, life is also characterized by unity, or features that all living things have in common

Ch. 1.2 Themes In Biology Diversity and Unity of Life The tree of life shows that all living things have descended with modification from a single common ancestor. Yet, there are many different lineages, or branches, representing different species

Ch. 1.2 Themes In Biology Evolution Natural Selection Decent with modification; the process in which the inherited characteristics within populations change over generations, such that genetically distinct populations and new species can develop Natural Selection Organisms that have certain favorable traits are better able to survive and reproduce successfully

Science as a Process Science is characterized by an organized process, called the scientific method, to learn how the natural world works There is no single method, but all involve a certain series of steps

Steps of the Scientific Method Observation The act of perceiving a natural occurrence that causes someone to pose a question Hypothesis A proposed explanation for the way a particular aspect of the world functions Prediction A statement that forecasts what would happen in a test situation if the hypothesis were true

Steps of the Scientific Method Experiment Used to test the hypothesis and its predictions Analysis and Drawing Conclusions Once the experiment is ended the data is analyzed and conclusions are formed Communication Results and conclusions are communicated to peers and the public

The Scientific Method

The Scientific Method Observations Start with an unexplainable observation about nature Example: Owls are nocturnal, and thus hunt at night…how are they able to do this?

The Scientific Method Forming a Hypothesis A good hypothesis can answer a question in a testable way Example: How do owls hunt at night?

The Scientific Method Design an Experiment Control group: normal standard against which biologists can compare results from experimental group Experimental group: identical to control group except for one factor… Independent variable: variable manipulated to test questions/hypothesis

The Scientific Method Run the experiment Collect data Repeat Draw conclusions on the data

The Scientific Method Another example….My flashlight isn’t working…come up with an answer using the scientific method…

Ch. 1.4 Tools and Techniques Microscopes Tools that extend human vision by making enlarged images of objects; examples in biology: cells, cell parts, molecules Types of Microscopes Compound light microscope Scanning electron microscope (SEM) Transmission electron microscope (TEM)

Ch. 1.4 Tools and Techniques Light Microscopes Shines light through a specimen, with two lenses that magnify the image. Specimen must be thin enough for light to pass through it If too large, specimens are cut into smaller, thinner pieces

Ch. 1.4 Tools and Techniques

Ch. 1.4 Tools and Techniques

Ch. 1.4 Tools and Techniques Magnification All microscopes come with an ocular lens (or lenses) and objective lenses Ocular (10x magnification) Objective (4x, 10x, 100x magnification) To calculate the power of magnification multiply the ocular magnification by the objective lens magnification being used

Ch. 1.4 Tools and Techniques Electron microscopes are used to see even more detail of an object Utilizes a beam of electrons to produce a larger image of the specimen Higher magnification and resolution than light microscopes Always black and white images Uses a vacuum which makes it unable to view live specimens

Ch. 1.4 Tools and Techniques Scanning Electron Microscope Passes a beam of electrons over the specimen’s surface. Sprays specimen with metal coating, which emits a shower of electrons. Produces a 3D image that can be magnified up to 100,000 times!

Ch. 1.4 Tools and Techniques Transmission Electron Microscope Transmits beam of electrons at a very thin slice of a specimen Greater resolution achieved Up to 200,000x magnification!