Biology 111Holyoke Walsh

What is Science???

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Science

The Goals of Science

1. Deals only with the Natural World

The supernatural is outside the realm of science

The Goals of Science

2. Collect & Organize Data

Goals of Science

3. Propose Explanations that can be tested

In Summary…..

• SCIENCE is a BODY of KNOWLEDGE that EXPLAINS the NATURAL World.

Science Begins with Observation – How are your Skills?

OBSERVATION

1. Quantitative – a quantity/number or measure

2. Qualitative – a quality/characteristic; description

Inference

• A logical interpretation based on prior knowledge

• Examples of Inferences?

• What can be the problem with inferences?

• http://www.youtube.com/watch?v=tiy1MeXzhfA

Hypothesis

• A proposed explanation; must be TESTABLE; written in an “If….then” format

1.If I give my dog Purina dog food for a month, then he will not shed as much.

2.If I use miracle grow then my plants will produce more tomatoes.

3.If I use the drug Avapro for a week then my blood pressure will be lower

Narrowing in on Science

• BIOLOGY – One Branch of Science

• Study of LIVING things

Copyright Pearson Prentice Hall

A Few Branches of Biology:– Zoologists– Botanists– Paleontologists– Cell Biologists– Geneticists– Microbiologists– Ecologists

Biology is very broad (Remember it is the study of LIVING things…and there are LOTS of

living things!!!!!)

Terminology rich; very descriptive and has it’s own

language~– Handout #1 – Give it a try

Copyright Pearson Prentice Hall

1-2 How Scientists Work

Scientists make educated guesses about how things work the way they do. These are called HYPOTHESIS.

How do scientists test hypotheses?

A hypothesis should be tested by an experiment in which only one variable is changed at a time.

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Scientific Method

1) Ask questions, make observations2) Gather information 3) Form a hypothesis (If…then)4) Set up a controlled experiment • Manipulated variable - the variable

that is deliberately changed (aka independent variable)Responding variable is variable that is observed (aka dependent variable)

5)Record and analyze results 6)Draw a conclusion7)Repeat & share findings

Scientific Method PracticeJordan is doing a science fair project on how music effects the growth of tomatoes. He has two tomato plants, Plant A and Plant B, that he grows in a window and gives the same amount of water. Plant A is exposed to classical music using headphones attached to the soil and plant B is not. Throughout the growth period, Jordan counts the number of tomatoes produced by each plant.

Plant A = 35 Tomatoes | Plant B = 55 Tomatoes

1) What is the control group?

2) What is the manipulated variable?

3) What is the responding variable?

4) What should Jordan’s conclusion be

5) Jordan needs to repeat the experiment, but his teacher says that he needs to improve his design. In his second experiment, what should he do different.

Scientific Method Practice

In the same science fair, Tina asks the question “Does caffeine increase the heart rate of an earthworm?” In Test 1, she measures the heart rate by looking at the earthworm under a microscopes, the earthworm has a heart rate of 50 bpm (beats per minute). In Test 2, she places a few drops of caffeine on the earthworm’s skin and measures the rate again. In this test, the heart rate is 68 bpm.

6) What is the manipulated variable in this experiment?

7) What is the responding variable in this experiment?

8) Tina’s experiment should have included a hypothesis. Using proper format, suggest a hypothesis for Tina’s experiment.

SpongeBob HWK

Fill & Chill:8 Characteristics of Living Things: Textbook 1-3 (page 15-17)

1) Life is Cellular- smallest unit of life unicellular = single celled (bacteria)multicellular = many cells (human)

2. REPRODUCTION: Organisms Reproduce to Pass on their Genetic Traits

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Two Types of Two Types of ReproductionReproduction

• Sexual Sexual ReproductionReproduction

• Involves 2 Involves 2 parentsparents

• Egg (n) fertilized Egg (n) fertilized by sperm (n) to by sperm (n) to make a zygote make a zygote (2n)(2n)

• Offspring Offspring DIFFERENT from DIFFERENT from parentsparents

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Two Types of Two Types of ReproductionReproduction

• Asexual Asexual ReproductionReproduction

• Involves a single Involves a single organism or cell organism or cell (2n)(2n)

• Cell dividesCell divides• Offspring Offspring

IDENTICAL to IDENTICAL to parent (2n)parent (2n)

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3. Cells Have a Genetic Code (DNA/RNA)

copyright cmassengalecopyright cmassengale

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• DNA (deoxyribose nucleic DNA (deoxyribose nucleic acid)acid) carries the genetic code carries the genetic code for all organismsfor all organisms

• All organismsAll organisms contain DNA contain DNA• DNA DNA codes for the proteinscodes for the proteins

that make up cells & do all that make up cells & do all the workthe work

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4. Organisms Grow & 4. Organisms Grow & DevelopDevelop

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4. Growth & 4. Growth & DevelopmentDevelopment

• Organisms Organisms growgrow by by producing MORE producing MORE CELLS & by cell CELLS & by cell ENLARGEMENTENLARGEMENT

• Organisms Organisms developdevelop as they mature into as they mature into an adult organisman adult organism

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5. Cells Require Food & 5. Cells Require Food & EnergyEnergy

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Food RequirementsFood Requirements• AutotrophsAutotrophs can make can make

their own foodtheir own food• PhotoautotrophsPhotoautotrophs use use

sunlight to make food sunlight to make food (photosynthesis) – ex?(photosynthesis) – ex?

• ChemoautotrophsChemoautotrophs use use chemicals such as iron chemicals such as iron & sulfur as their & sulfur as their energy – ex?energy – ex?

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Food RequirementsFood RequirementsTypes of Heterotrophs: (cannot make own food)Types of Heterotrophs: (cannot make own food)• Holozoic nutrition: Complex food is taken into a Holozoic nutrition: Complex food is taken into a

specialist digestive system and broken down into specialist digestive system and broken down into small pieces to be absorbed. This consists of 5 small pieces to be absorbed. This consists of 5 stages, ingestion, digestion, absorption, assimilation stages, ingestion, digestion, absorption, assimilation and and elimination. ….includes . ….includes herbivores/carnivores/omnivoresherbivores/carnivores/omnivores

• Saprozoic/Saprobes: Organisms feed on dead : Organisms feed on dead organic remains of other organisms. organic remains of other organisms.

• Parasitism: Organisms obtain food from other living Parasitism: Organisms obtain food from other living organisms (the host), with the host receiving no organisms (the host), with the host receiving no benefit from the parasite. benefit from the parasite.

• Mutualism: A symbiotic relationship between Mutualism: A symbiotic relationship between organisms, with each contributing and benefiting organisms, with each contributing and benefiting from each other.from each other.

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MetabolismMetabolism

• Sum of all the chemical Sum of all the chemical reactions in an organismreactions in an organism

• All require energyAll require energy• SunlightSunlight is the ultimate is the ultimate

energy for life on Earth energy for life on Earth

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MetabolismMetabolism

•Cellular RespirationCellular Respiration – Cells releasing the chemical Cells releasing the chemical

energy stored in foodsenergy stored in foods

6O6O22 + C + C66HH1212OO66 6CO 6CO22 + + 6H6H22OO

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6. Organisms Respond to 6. Organisms Respond to StimuliStimuli

• Organisms Organisms RespondRespond to to stimulistimuli (Temperature, Water, (Temperature, Water, Food Supplies, etc.) Food Supplies, etc.) In Order In Order To Survive & ReproduceTo Survive & Reproduce

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7. Homeostasis• Keeping The Internal Environment

of The Cell or Organism Within a balance necessary for life

• Often called “equilibrium”• Stable internal conditions of pH,

temperature, water balance, etc.

8. Living Things Evolve

• Groups Of Organisms (Not Individuals) Change Over Time In Order To Survive Changing Environments.

• Fossil records show changes in groups of organisms

HWK

• Read sections 1-3/1-4 in Chapter 1

• Complete Chapter 1 Review

Biological Equipment

• What is the most common tool used by biologists???

Leeuwenhoek

• Father of Microbiology…made many improvements in microscopy• made a simple microscope (mid 1600’s)• magnified 270X • Early microscope lenses made images larger but the image was not

clear

MODERN MICROSCOPES

• A microscope is simple or compound depending on how many lenses it contains

• A lens makes an enlarged image & directs light towards you eye

• A simple microscope has one lens

• Similar to a magnifying glass

• Magnification is the change in apparent size produced by a microscope

COMPOUND MICROSCOPE

• A compound microscope has multiple lenses – (ocular & objective lenses)

Do You Know The Parts?

• http://www.biologycorner.com/microquiz/#

• (handout #5)

• Do you know how to focus a scope??

• Make a dry/wet mount??

• Put it away properly??

STEREOMICROSCOPEaka: dissecting microscope

• creates a 3D image

TOTAL MAGNIFICATION• Powers of the eyepiece (10X) multiplied by

objective lenses determine total magnification.

ELECTRON MICROSCOPES

• More powerful; some can magnify up to 1,000,000X

• Use a magnetic field in a vacuum to bend beams of electrons

• Images must be photographed or produced electronically

Scanning Electron Microscope (SEM)Electron microscope image of a spider

• produces realistic 3D image • only the surface of

specimen can be observed

Electron microscope image of a fly foot

SEM cont…

Guess?

Guess??

Guess??

Guess??

Transmission Electron Microscope (TEM)

• produces 2D image of thinly sliced specimen

• detailed cell parts (only inside a cell) can be observed

Time for Biological Drawings

• See handout #6