Chapter 1: The Science of Life. Section 1: The World of Biology Objectives – Relate the relevance...

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

https://www.youtube.com/watch?v=VgTPg99V_JM


• Characteristics of Life– Living things share the same 7 characteristics:• Organization and cells• Response to stimuli• Homeostasis• Metabolism• Growth and development• Reproduction• Evolution


• 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


• 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


• 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


• Characteristics of Life– Response to Stimuli• https://www.youtube.com/watch?v=TTyuisUCcvo

• https://www.youtube.com/watch?v=vtLzxEYSe30

https://www.youtube.com/watch?v=TTyuisUCcvo

https://www.youtube.com/watch?v=vtLzxEYSe30


• 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

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

Homeostasis


• Characteristics of Life–Metabolism• Metabolism is the sum of

all the chemical reactions that take in and transform energy and materials from the environment.


• 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


• Characteristics of Life– Reproduction• Living organisms pass on hereditary information from

parents to offspring, also called reproduction


• Characteristics of Life– Change through time• Populations of living

organisms evolve or change through time


• 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


• 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


• 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


• Evolution– 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


• Observations– Start with an unexplainable observation about

nature– Example: Owls are nocturnal, and thus hunt at

night…how are they able to do this?


• Forming a Hypothesis– A good hypothesis can answer a question in a

testable way– Example: How do owls hunt at night?


• 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


• Run the experiment– Collect data – Repeat– Draw conclusions on the data


• 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)


• 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


• 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


• 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


• 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!


• Transmission Electron Microscope– Transmits beam of electrons at a very thin slice of

a specimen– Greater resolution achieved– Up to 200,000x magnification!

Chapter 1: The Science of Life. Section 1: The World of Biology Objectives – Relate the relevance...

Documents

Transcript of Chapter 1: The Science of Life. Section 1: The World of Biology Objectives – Relate the relevance...