Intro to Life ScienceIntro to Life ScienceWhat is Science?

Living Things

Where Does Life Come From?

Classifying Life

1-1: What is Science ?1-1: What is Science ?How do you define science?

Science: an organized way of studying things and finding answers to questions

Critical thinking: a process that uses certain skills to solve problems

Solving ProblemsSolving ProblemsSolving problems requires

organization

Scientific methods: an organized way to solve a problem using a series of procedures◦requires critical thinking

Scientific MethodsScientific MethodsState the problem/Ask a question

Gather information

Form a hypothesis:a prediction that canbe tested

Scientific MethodsScientific MethodsExperiment:

◦Control: standard of comparison in an experiment; cannot change

◦Variable: something in an experiment that can change

An experiment should have only one variable.

tests the hypothesis

Scientific MethodsScientific MethodsAnalyze data

Draw conclusions

Report results◦allows other scientists to repeat

same experiment

7 Steps to Solve a 7 Steps to Solve a ProblemProblem

State the Problem

Gather Information

Form a Hypothesis

Perform an Experiment

Analyze Data

Draw Conclusions

Hypothesis Supported

Hypothesis not Supported

RepeatMany Times

ReviseHypothesis

Developing TheoriesDeveloping TheoriesThe results can

be used to develop a scientific theory◦ an explanation of

things or events based on scientific knowledge; the result of many observations and experiments

Not just simply a guess or opinion!!!

LawsLawsScientific law: a

statement/description about how things work in nature; seems to be true all the time◦Ex. Law of Gravity

Less likely to change than theories

Scientific UnitsScientific UnitsMust make accurate measurements

in experiments and investigationsScientists use:

◦International System of Units (SI) Standard system of measurements used by

scientists Uses

Gram Meter Liter Second Celsius

MassLengthVolumeTimeTemperature

Lab SafetyLab SafetyMust be safe in the lab

Follow all safety rules and teacher’s instructions at all times

1-2: Living Things 1-2: Living Things What does it mean to be alive?Any living thing is called an

organism May have different behaviors and food needs, but all organisms have similar traits.

Characteristics of LifeCharacteristics of Life1. Organization

◦ Living things are organized◦ Made of cells: the smallest unit of

an organism that carries on the functions of life

◦ Each cell has: an orderly structure hereditary material (DNA)

Characteristics of LifeCharacteristics of Life

2. Responsiveness◦ Living things respond◦ Stimulus: anything that causes

some change in an organism◦ Response: the way an organism

reacts to a stimulus Ex: Someone hitting you

◦ Homeostasis: maintaining proper conditions inside an organism

Characteristics of LifeCharacteristics of Life

3. Energy◦ Living things use energy

◦ Animals get energy from food

◦ Some organisms use the sun to make energy Ex: plants

Characteristics of LifeCharacteristics of Life

4. Growth and Development◦ Living things grow and develop◦ Growth

can be an increase in number of cells (multi-cellular organisms)

can also be an increase in the size of the cell (unicellular organisms)

◦ Development: changes that take place during the life of an organism

5. Reproduction◦ Living things reproduce◦ Creating offspring◦ Without reproduction, organisms

would cease to exist

Characteristics of LifeCharacteristics of Life

What Do Organisms What Do Organisms Need?Need?A Place to Live

◦provides for all the organism’s needs◦environment limits where organisms

can live

Raw Materials

◦Water, proteins, fats, and sugars◦Water is important for all organisms

1-3: Where Does Life Come 1-3: Where Does Life Come From?From?Can mice come from grains? Can

earthworms come from the rain?Spontaneous generation: idea

that living things come from non-living things

Theory finally disproved by Louis Pasteur

Biogenesis: living things only come from other living things

Life’s OriginsLife’s OriginsHow did life on Earth begin?5 billion years ago, Earth was

formed from dust and gasEarth’s atmosphere had no

oxygen but it did have◦Ammonia◦Hydrogen◦Methane◦Water vapor

Life’s OriginsLife’s Origins

Alexander Oparin hypothesized that the gases combined to form more complex compounds found in living things

Miller and Urey tested Oparin’s hypothesis◦Found that chemicals in living things

could be produced◦Did not prove that life began this way

1-4: Classifying Life1-4: Classifying LifeWhat is classification?

◦Grouping similar items

Organisms can also be classified into groups

Aristotle◦first classification system more than

2000 years ago◦grouped organisms into plants and

animals

Classifying LifeClassifying Life

Carolus Linnaeus◦Developed a new system based on

similar structures of organismsScientists now study fossils, DNA,

and embryos to classify based on phylogeny◦evolutionary history of an organism◦shows how an organism has changed

over timeToday, we have 6 kingdoms of

classification◦Kingdom—Phylum—Class—Order—

Family—Genus—Species

Six KingdomsSix Kingdoms

Kingdoms are the first and largest category

Smallest classification category is a species◦Organisms belonging to the same

species can mate and produce fertile offspring

A. Bow-Head whale family Balaenidea

B. Ganges dolphin family Platanistidae

C. Killer Whale family Delphinidae

D. Right whale family Balaenidea

This is the classification of the bottle-nosed dolphin. Which of the following organisms from the order Cetacea is most closely related to the bottle-nosed dolphin?

Scientific NamesScientific NamesCommon names can be

extremely misleading

Binomial nomenclature◦Two-word system used by Linnaeus

to name species; used today◦First word identifies the genus: group

of similar species◦Second word tells something about

the species

Haliaeetus leucocephalus

Using Scientific NamesUsing Scientific NamesScientific names are used to:

◦Avoid mistakes◦Show that organisms in the same

genus are related◦Give descriptive information◦Allow information to be organized

easily

Identifying OrganismsIdentifying Organisms2 types of tools used

◦Field guides: descriptions or illustrations of organisms Ex. Bird watching

◦Dichotomous keys: detailed lists of identifying characteristics that include scientific names arranged in steps with two descriptive

statements at each step

Example:1. Does the organism have a

round body?Yes = Go to number 2No = Go to number 4

2. Does the organism have 2 eyes?

Yes = BOT TOTNo = Go to number 3

3.Does the organism have 4 antennae?

Yes = BOT FOTNo = BOT BOT

Dichotomous Key