Sorting Out Life- Exploring and Classifying Life

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Sorting Out Life- Exploring and Classifying Life

Objectives

Distinguish between living and nonliving things.

Identify what living things need to survive.

Organism

Any living thing is called an ______________________

They have different behaviors and food needs. In spite of these differences, all organisms have similar traits.

6 CHARACTERISTICS OF LIVING THINGS

1. Cellular organization 2. Respond to their surroundings 3. Use energy 4. Grow and develop 5. Reproduce 6. Contain Similar Chemicals

1. Cellular Organization

All organisms are made of small building blocks called cells.

A ___________ is the smallest unit of an organism that carries on the functions of life. It’s the basic unit of structure and function in an organism.

Cells are so small that you need a _____________________________________ to see them (more on the microscope and cells later)

Cells take in materials from their surroundings and use them in complex ways.

Each cell has an orderly ________________________ and contains hereditary material.

The hereditary material contains instructions for cellular organization and function.

Scientists organize cells (cellular organization) as Unicellular or multi-cellular.

_________________________ means single-celled organisms.

Unicellular organisms include bacteria, the most numerous organisms on Earth.

_________________________ organisms are composed of many cells that are specialized.

Examples of multi-cellular organisms found in your body are muscle cells and nerve cells

2. Respond to their Surroundings

Anything that causes some change or reaction in an organism is a ____________________ (plural, stimuli).

The reaction to a stimulus is a _______________________________.

It’s an action or change in behavior. Often that response results in movement. Living things also respond to stimuli that occur inside

them.

An organism’s ability to keep the proper conditions inside no matter what is going on outside the organism is called ______________________.

Homeostasis is a trait of all living things.

3. Use Energy

The energy used by MOST organisms comes either directly or indirectly from the__________________________.

Plants and some other organisms use the Sun’s energy and the raw materials carbon dioxide and water to make food. (Photosynthesis)


You and most other organisms can’t use the energy of sunlight directly. Instead, you take in and use food as a source of energy.

You also use energy for growth and repair.

Some bacteria live at the bottom of the oceans and in other areas where sunlight cannot reach. They can’t use the Sun’s energy to produce food.

Instead, the bacteria use energy stored in some _______________compounds and the raw material carbon dioxide to make food.

(Chemosynthesis)

Many of these bacteria do not need oxygen to release the energy found in their food.

4. Grow and Develop

Growth of many-celled organisms is mostly due to an increase in the number of cells. _______________ is the process of becoming larger.

In one-celled organisms, growth is due to an increase in the size of the cell.

Organisms change as they grow.

All of the changes that take place during the life of an organism are called development. ______________________ is the process of change

that occurs during an organism’s life to produce a more complex organism

__________________ is the length of time an organism is expected to live.

Your life span is about 80 yrs; A pine tree can be 4,600 years

5. Reproduce

Cats, dogs, alligators, fish, birds, bees, and trees eventually reproduce.

_________________, or produce offspring that are similar to the parents. Living things arise from living things through reproduction.

Living things reproduce themselves in many different ways.

Beetles, like most insects, reproduce by laying eggs.

Without reproduction, living things would not exist to replace those individuals that die. Organisms reproduce at different rates. Bacteria-

minutes; Trees- years

6. Similar Chemicals

Organisms contain similar chemicals

The most abundant chemical in cells is ___________________.

Another chemical called carbohydrate is a cell’s energy source.

Proteins and lipids(fats) are the building materials of cells.

Nucleic acids are the ____________________ materials that direct the cell’s activities.

4 Basic things all living things need

All organisms need 4 basic things to live: 1. Living Space, 2. Food (raw materials), 3. Water (raw materials), 4. Stable internal conditions (Homeostasis)

To survive, all living things need a place to live and raw materials.

The raw materials that they require and the exact place where they live can vary.

1. Living Space

Living Space- Because space on Earth is ____________________, some organisms _______________________ for food and space.


The environment limits where organisms can live. Not many kinds of organisms can live in extremely hot or extremely cold

environments. Most cannot live at the bottom of the ocean or on the tops of mountains.

An organism’s surroundings must provide for all of its needs.

2. Water (Raw materials)

__________________ is important for all living things. Plants and

animals take in and give off large amounts of water each day.

Most organisms are composed of more than 50 percent

water. You are made of ________________ percent water.

3. Food (Raw materials)

Living things are made up of substance such as proteins, fats

(lipids), and sugars. Animals take in most of these substances from

the foods they eat.

Organisms that cannot make their own food are called

________________________________.

Plants and some bacteria _________________________ them using raw materials from their surroundings

Organisms that make their own food are called __________________________.

Heterotrophs consume autotrophs (Plants) or other heterotrophs (animals)

Raw Materials Recycled

When organisms die, substances in their bodies are broken down and released into the __________________ or air. ---SOIL FORMATION!

The substances can then be used again by other living organisms.- RECYCLING OF MATTER

4. Stable Internal Conditions

Because conditions in their surroundings can change, organisms must be able to keep the conditions inside their bodies constant.

The maintenance of stable internal conditions despite changes in surroundings is called ______________________________.

An example is you body temperature remaining relatively constant even-though the temperature outside is changing.

Objectives

Describe experiments about spontaneous generation.

Explain how scientific methods led to the idea of biogenesis.

Spontaneous Generation

Before the seventeenth century, some people thought that insects and fish came from mud; flies came from rotting meat, that earthworms fell from the

sky when it rained, and that mice came from grain.

The idea that living things come from nonliving things is known as ____________________________________________.

From the late seventeenth century through the middle of the eighteenth century, experiments were done to test the theory of spontaneous generation.


Redi and Pasteur

Biogenesis

It was not until the mid 1800s that the work of Louis Pasteur provided enough evidence to___________________ the theory of spontaneous generation

It was replaced with ___________________________, which is the theory that living things come only from other living things.

Life’s Origins

Some scientists hypothesize that about 5 ________________________ years ago, Earth’s solar system was a whirling mass of gas and dust. They

hypothesize that the Sun and planets were formed from this mass.

In 1924 Alexander I. Oparin suggested that Earth’s early atmosphere had no oxygen but was made up

of the gases ammonia, hydrogen, methane, and _______________________________.

Oparin hypothesized that these gases could have combined to form the more complex compounds

found in living things.

American scientists Stanley L. Miller and Harold Urey set up an experiment to test Oparin’s hypothesis

in 1953. They sent electric currents through a mixture of gases thought to be in Earth’s early

atmosphere. When they cooled they formed and ocean like liquid that contained materials found in

present day cells. Although the Miller-Urey experiment showed that chemicals found in living things

could be produced, it did not prove that life began in this way.

Objectives

Describe how early scientists classified living things


Explain how similarities are used to classify organisms

Explain the system of Binomial Nomenclature

Demonstrate how to use a Dichotomous Key

Classification

Libraries group similar types of books together. When you place similar items together, you _________________________ them.

Organisms also are classified into groups. ___________________________________ is the process of grouping things based on their similarities.

Biologists use classification to organize living things into _________________________ so that the organisms are easier to study.

The scientific study of how living things are classified is called taxonomy. A biologist who specialize in classifying organisms is called a taxonomist.

Taxonomy is useful because once an organism is classified, a scientist knows a lot about that organism.

For example, if you know that a crow is classified as a bird, then you know that a crow has wings, feathers, and a beak.

History of Classification

More than 2,000 years ago, a Greek named Aristotle observed living things. He decided that any organism could be classified as either a _________ or

an __________________. Then he broke these two groups into smaller groups.

Animal categories included hair or no hair, four legs or few legs, and blood or no blood.

Carolus Linnaeus developed a new system of grouping organisms.

His classification system was based on looking for organisms with similar_________________________. For example, plants that had similar

flower structure were grouped together. Modern scientists use similarities in structure to classify organisms. They also use similarities in both

external and internal features. Specific characteristics at the cellular level can be used to infer the degree of relatedness among organisms.

In addition, scientists study fossils, hereditary information, and early stages of development. They use all of this information to

determine an organism’s phylogeny. ___________________________(fi LAH juh nee) is the evolutionary history of an

organism, or how it has changed over time.

Binomial Nomenclature

Linnaeus’s naming system for organisms called___________________ nomenclature, in which each

organism is given a ________________________ name. It is the system used by modern

scientists to name organisms.

The first part of an organism’s scientific name is its genus.

A __________ is a classification grouping that contains similar, closely related organisms.

Examples would be claws or hunting other animals. (physical characteristics also

how they interact with their environment).


The second part of an organism’s scientific name sets each species apart from one another in the genus. It might tell you something about the

organism— what it looks like, where it is found, or who discovered it

A ________________________ is a group of similar organisms that can mate and produce fertile offspring.

Two-word scientific names are used for four reasons.

1. They help avoid mistakes.

2. Organisms with similar evolutionary histories are classified together.

3. Scientific names give descriptive information about the species.

4. Scientific names allow information about organisms to be organized easily and efficiently.

The Classification System

The Genus and Species is part of the Classification System developed by Linneaus

Modern biologists classify organisms into _________________levels: domain, kingdom,

phylum, class, order, family, genus, and species.

Organisms are grouped by their __________________ characteristics.

Kingdoms

A kingdom (or Domain by some) is the first and largest category. Organisms are placed

into kingdoms based on various characteristics.

Six Kingdoms

1. Archaebacteria

2. Eubacteria

3. Protista

4. Fungi

5. Plantae

6. Animalia

Dichotomous Keys & Field Guides

Tools used to identify organisms include field guides and dichotomous keys.

Many different ______________________ are available.

Most have descriptions and illustrations of organisms and information about where each

organism lives.

You can identify species from around the world using the appropriate field guide.


A dichotomous key is a detailed list of identifying characteristics that includes scientific names

Dichotomous keys are arranged in steps with two descriptive statements at each step


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Sorting Out Life- Exploring and Classifying Life