Do Now

What is the correct way to read the volume of a liquid in a graduated cylinder?

Do Now

What is the correct way to read the volume of a liquid in a graduated cylinder?

The correct volume is found at the bottom of the meniscus.

Steps of the Scientific Method

1. Problem or Question2. Observation and Research3. Hypothesis4. Experiment5. Collect Data6. Analyze Data7. Conclusion8. Communicate Results

Steps of the Scientific Method

1. Problem or Question:Develop a question or problem that can be solved through experimentation.

Steps of the Scientific Method

1. Problem or Question:Develop a question or problem that can be solved through experimentation.

Example: What is the optimum amount of water for maximum seed germination?

Steps of the Scientific Method

1. Problem or Question:Develop a question or problem that can be solved through experimentation.

Example: What is the optimum amount of water for maximum seed germination?

Non-example: What is the best show on TV?

Steps of the Scientific Method

2. Observation and Research:

Make observations and research your topic of interest.

Steps of the Scientific Method

3. Hypothesis: A hypothesis predicts a possible answer to our problem or question.

Steps of the Scientific Method

3. Hypothesis: A hypothesis predicts a possible answer to our problem or question.

It is an educated guess about the relationship between the independent and dependent variables.

Hypothesis

In other words…

Our hypothesis is our educated guess about a cause and effect relationship.

We are trying to correctly match a cause to an effect

Steps of the Scientific Method

4. Experiment:• Design and follow a procedure.

• Include a detailed materials list.

• The outcome must be quantifiable (measureable).

Steps of the Scientific Method

5. Collect Data:

Data is often collected and presented in tables.

AIDS diagnoses and deaths of persons with AIDS in the USA by year

Year Cases Diagnosed Deaths

1981 339 130

1982 1201 466

1983 3153 1511

1984 6368 3526

1985 12044 6996

1986 19404 12183

1987 29105 16488

1988 36126 21244

1989 43499 28054

1990 49546 31836

1991 60573 37106

1992 79657 41849

1993 79879 45733

1994 73086 50657

1995 69984 51414

1996 61124 38074

1997 49379 21846

1998 43225 19005

1999 41356 18491

2000 41267 17741

2001 40833 18524

2002 41289 17557

2003 43171 18017

Steps of the Scientific Method

6. Analyze Data: make graphs and charts, look for patterns in data

Steps of the Scientific Method

7. Conclusion: statement that accepts or rejects hypothesis based on data; recommendations for further research

Steps of the Scientific Method

8. Communicate Results: sharing information allows others to build upon it

Characteristics of Living Things

Living Things:• are made up of units called cells• reproduce• are based on a universal genetic code• grow and develop• obtain and use material and energy• respond to their environment• maintain a stable internal environment• Taken as a group, living things change over

time

Life Processes

Living things rely on many of the same processes to stay alive.

Yet they carry these processes out in diverse ways.

Life Processes:

• Nutrition• Transport• Respiration• Excretion• Regulation• Synthesis• Growth• Reproduction

In Living Things…

Nutrition: refers to mechanisms for obtaining and processing foods

In Living Things…

Transport: absorbing materials through cell membranes; circulating materials throughout the organism

In Living Things…

Respiration: refers to mechanisms for converting food energy into cell energy

In Living Things…

Excretion: refers to mechanisms for eliminating waste products from the body

In Living Things…

Regulation: refers to mechanisms for controlling and coordinating life activities

• Homeostasis: maintenance of a stable internal environment despite changes in the external (outside) environment

• Metabolism: all the chemical activities that occur within an organism and are necessary to sustain life

In Living Things…

Synthesis: refers to mechanisms for assembling materials needed by the body

In Living Things…

Growth: refer to mechanisms for increasing in size (by increasing cell size or cell number)

In Living Things…

Reproduction: refers to mechanisms for producing more members of their kind.

Which animals are most closely related to each other?• What are some ways these animals are alike? • How are they different?

Why did people create systems for classifying living things?

In order to organize them for study…

The classification system we use today was created by Carl Linnaeus in the 1700’s.

It is hierarchical, which means that it consists of levels:

The forerunner to the classification system we use today was created by Carolus Linnaeus in the 1700’s.

It is hierarchical, which means that it consists of levels:KingdomPhylum (plural: phyla)ClassOrderFamilyGenus (plural: genera)Species

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Taxonomic Nomenclature

Each level is called a taxon (plural: taxa)

Nomenclature: a naming system for a subject or field of study

So, taxonomic nomenclature is the system for naming organisms according to Linnaeus’ hierarchy.

Taxonomic Nomenclature

Every name is in the Latin language.

Biologists use a two-name system for organisms called binomial nomenclature (“two-name naming”)

Genus (always upper case) species (always lower case)

Linnaeus’ system only had two kingdoms: plants and animals

Today, organisms are grouped into six kingdoms:1. Archaebacteria2. Eubacteria

single-celled organisms that don’t have a nucleus. Bacteria make up the entire kingdom. There are more forms of bacteria than any other organism on Earth.3. Plants4. Animals5. Fungi6. Protists

mostly single-celled organisms that have a nucleus. Examples of protists include some algae, paramecium, and amoeba.

What is a dichotomy?

di- = two or split -otomy = cut

What is a dichotomy?

di- = two or split -otomy = cut

A dichotomy is any splitting of a whole into exactly two non-overlapping parts

What is a dichotomy?

di- = two or split -otomy = cut

A dichotomy is any splitting of a whole into exactly two non-overlapping parts

The members of one group do NOT fit into the other group!

What is a dichotomy

A dichotomy is any splitting of a whole into exactly two non-overlapping parts

Example:Our Living Environment class can be divided into:1. Girls2. Boys

Dichotomous Keys

A dichotomous key is a tool for determining the identity of something (like the name of a butterfly, a plant, or a bird) by going through a series of choices that leads us to the correct name of the organism

The naming of the cell

In the 1600’s, the English scientist Robert Hooke used the first compound microscope to discover plant cells, or more precisely, Hooke had been viewing the cell walls in cork tissue.

In fact, it was Hooke who coined the term "cells": the boxlike cell walls of cork reminded him of the cells of a monastery.

Cell Theory

• All living things are made up of cells

• Cells are the basic units of structure and function in living things

• New cells are produced from living cells

Key Terms!

Cell: basic living unit of structure and function

Cell membrane: a thin, flexible barrier surrounding the cell• Controls what enters and leaves the cell• Protects and supports the cell

Cell wall: strong supporting layer surrounding the cell membrane. Found in plants, algae, fungi and many prokaryotes

Key Terms: Organelles

Organelles: • small structures (“little organs”) which

perform specific functions inside the cell

Cell membrane (aka plasma membrane):• surrounds and protects cell• separates cell contents from the environment

Key Terms: Organelles

Nucleus: • “control center of the cell”• surrounded by nuclear membrane• contains the genetic material (DNA)

Key Terms!Nucleus: membrane-enclosed that holds the cell’s genetic material (DNA) and controls many of the cell’s activities.

karyo- • from Greek karyon, meaning “kernel” • seen in words that refer to the nucleus

Prokaryotes: cells lack a nucleus

Eukaryotes: cells have a nucleus

Key Terms: Organelles

Ribosomes: • tiny organelles suspended in cytoplasm• also found attached to membrane of

endoplasmic reticulum• protein synthesis happens here

Key Terms: Organelles

Mitochondria: • “powerhouse of the cell”• Where most cellular respiration happens

(process of releasing energy from nutrient molecules like glucose and synthesizing the body’s main energy molecule, ATP)

Key Terms: Organelles

Vacuoles: • fluid-filled organelles surrounded by

membranes• multi-purpose: digestion in unicellular

organisms, storage of excess water, transport, etc.

Key Terms: Organelles

Chloroplasts: • small pigment-containing organelles• found in cytoplasm of plants, algae, some

protists• photosynthesis happens here

Key Terms: Organelles

Chlorophyll: • green pigment in chloroplasts that absorbs

energy from sunlight

Key Terms: Organelles

Photosynthesis: • the most common type of autotrophic

nutrition• organism uses carbon dioxide and water from

the environment and energy from sunlight to synthesize glucose, an organic nutrient.

Key Terms: Organelles

Cell wall: • nonliving structure found outside cell

membrane of plant, algae and fungal cells• provides strength and rigidity but allows

materials to pass in and out of cell

Key Terms: Organelles

Cyclosis: movement of cytoplasm

Passive Transport: Key Terms

1. Solute: the substance that is dissolved in a solvent to make a solution

2. Solvent: substance in which a solute is dissolved to make a solution

3. Concentration: the mass of solute in a given volume of solution, or mass/volume

Passive Transport: Key Terms

4. Concentration gradient: a gradual difference in the concentration of a dissolved substance in a solution between an area of high concentration and an area of lower concentration

5. Equilibrium: state that occurs when the concentration of a solute is the same throughout a solution

6. Permeable: able to be passed through, especially by liquids or small particles

Passive Transport: Key Terms

7. Diffusion: process by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated

8. Osmosis: diffusion of water through a selectively permeable membrane into a solution of higher solute concentration that tends to equalize the concentrations of solute on the two sides of the membrane

Passive Transport: OSMOSIS

Passive Transport: Key Terms

9. Isotonic: (“same strength”) two solutions in which concentration of solutes is the same

10. Hypotonic: (“below strength”) the solution with the lower concentration of solutes, when comparing two solutions

11. Hypertonic: (“above strength”) the solution with the higher concentration of solutes, when comparing two solutions

Passive Transport: Key Terms

12. Passive transport: movement of substances across a cell membrane that does not require energy

Smaller molecules such as glucose, oxygen, amino acids, carbon dioxide, and water can diffuse right through the cell membrane like air through a screen door!

Larger molecules such as complex carbohydrates, proteins, and lipids cannot fit, because they are TOO BIG.

Glucose vs Starch: Molecule SMACKDOWN!!!!

The RATE of diffusion is affected by:

• Concentration gradient• Distance particles have to travel• Size of particles• Temperature• Surface area of cell membrane

Water is Special!

Osmosis: diffusion of water through a selectively permeable membrane into a solution of higher solute concentration that tends to equalize the concentrations of solute on the two sides of the membrane

Isotonic: (“same strength”) two solutions in which concentration of solutes is the same

Hypotonic: (“below strength”) the solution with the lower concentration of solutes, when comparing two solutions

Hypertonic: (“above strength”) the solution with the higher concentration of solutes, when comparing two solutions

What happens to BLOOD cells?