Unit 4 Lesson 2: Classification of Living Things

Question 1

Since ancient times, people have worked to develop a system for classifying millions of different kinds of plants, animals, bacteria, and other living things on Earth. This classification, called

Answer 1

Taxonomy

Question 2

Early civilizations organized living things into two groups:

Answer 2

those with blood and those without blood.

Question 2

Taxonomy is a living science, meaning it is changing as new discoveries are made. How do Modern taxonomical systems classify animals?

Answer 2

Modern taxonomical systems are moving from classifying organisms by shared superficial characteristics, to grouping them by their genetic relationships. In the same way that Medieval naturalists used their increasing knowledge to better group and understand organisms, today’s scientists work with new technologies to deepen our understanding of the relationships between living things.

Question 2

taxonomy

Answer 2

the branch of science concerned with naming, classifying, and describing the relationships between all living things on Earth

Question 3

How did Aristotle classify animals

Answer 3

The Greek naturalist Aristotle used a system that separated plants from animals. Aristotle further organized animals into groups based on their physical characteristics (having live births, having four legs, laying eggs, etc.).

Question 4

What does taxonomy allow people to do

Answer 4

This classification, called taxonomy, allows people to understand the relationships between living things and to study their similarities, differences, and needs.

Question 5

botanist

Answer 5

plant scientist

Question 6

What did Swedish botanist (plant scientist) named Carolus Linnaeus do

Answer 6

During the 1700s, a Swedish botanist (plant scientist) named Carolus Linnaeus developed a new system of classification which became the standard for the modern world. Linnaeus created a standardized system for identifying and naming plants and animals

Question 6

How did Linnaeus group people

Answer 6

He organized living things into large kingdoms of plants and animals. Within each kingdom, he further classified living things into smaller and smaller groups.

Question 7

Animals, for instance, can be classified as follows:

Answer 7

Phylum (with or without a backbone)
Class (mammal, bird, fish, insect, reptile, amphibian)
Order
Family
Genus
Species

Question 8

Individual species are officially labeled with the name of their

Answer 8

genus and species.

Question 9

For example, the scientific label for modern human beings is

Answer 9

Homo sapiens

Question 10

A human’s full taxonomic classification is as follows:

Answer 10

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Hominidae
Genus: Homo
Species: sapiens

Question 11

While Linnaean classification is still the basis for taxonomy, new ideas and technologies have expanded and changed his system. For example: What did Darwin do

Answer 11

Darwin’s discoveries regarding evolution helped scientists to better understand the complex relationships among living things. In particular, scientists have learned that the appearance of a modern animal does not necessarily reflect its evolutionary path or its relationship to other animals.

Question 12

What is an example of Darwins idea by Thomas Henry Huxley

Answer 12

An example of this is Thomas Henry Huxley’s use of fossils to argue that birds are directly descended from (and thus related to) dinosaurs.

Question 13

While Linnaean classification is still the basis for taxonomy, new ideas and technologies have expanded and changed his system. For example: Discovery of the microscope:

Answer 13

The invention of the microscope led to the discovery of living organisms too small to be seen with the naked eye or a magnifying glass. Bacteria, viruses, and archaea (single celled organisms without nuclei) are all organisms that were unknown to Linnaeus. They were later classified into additional kingdoms. Currently, there are six kingdoms used by scientists.

Question 14

While Linnaean classification is still the basis for taxonomy, new ideas and technologies have expanded and changed his system. For example: In the last twenty years, several new taxonomic systems have been suggested by researchers who are discovering new life forms and uncovering their relationships to one another. Describe the one suggested in 2015

Answer 14

One system, suggested in 2015, includes seven kingdoms. Separate kingdoms are recommended for specific forms of life such as fungi (spores such as mushrooms), protozoans (a particular type of single-celled organism), and archaea.

Question 15

People who study taxonomy, called ….

Answer 15

People who study taxonomy, called systematists, are still engaged in the process of discovering new life forms and classifying them.

Question 16

paleontologist

Answer 16

scientist who studies pre-human life

Question 17

What do paleontologists do

Answer 17

Meanwhile, paleontologists are constantly discovering new fossil and DNA evidence that changes our views of exactly how specific life forms evolved.

Question 18

What is the Linnaean classification system?

Answer 18

The Linnaean classification system, created by the Swedish botanist Linnaeus, is the system used to name and classify all living things on Earth.

Question 19

As an organism is placed within each group of the Linnean levels, the traits that classify it become more and more specific. Where whold animal with a backbone be placed?

Answer 19

An animal with a backbone will be placed in the phylum Chordata (a word that simply means “having a spinal cord”).

Question 20

Developing the rules of taxonomy is somewhat challenging. Elaborate

Answer 20

One of the original taxonomic systems classified all life as either plant or animal. That’s it. From there, things could become a bit more specific. Animals or plants could be classified as belonging to the air, or to the water. However, this system did not account for organisms like ducks. Where should they be classified? A duck is not clearly an air animal, or a water animal. Ducks fly. They walk on the ground and they live in the water. Obviously, this method of classification did not work well for all organisms.

Question 21

If that animal has fur and milk glands, it belongs to the order

Answer 21

Mammalia, the mammals.

Question 22

The smallest groups in the Linnaean system are

Answer 22

genus and specie

Question 23

An organism’s genus and species make up its

Answer 23

scientific name

Question 24

What is the scientifc names for humans

Answer 24

Humans, for instance, belong to the genus Homo and the species sapiens, so their scientific name is Homo sapiens.

Question 25

Because a species’ name comes from those smallest two categories, Linnaeus called his system

Answer 25

binomial nomenclature

Question 26

binomial nomenclature

Answer 26

Binomial is a Latin word that means “two”, and nomenclature is a word that means “name”.

Question 27

The hierarchies Linnaeus developed look like this:

Answer 27

Kingdom Phylum Class Order Family Genus Species

Question 28

Finally, in 1990, a microbiologist called Carl Woese proposed a big change to taxonomy. What did he propose?

Answer 28

Building off the Linnaean system, Woese proposed that a higher category than kingdoms be added. He called that category “domains”.

Question 29

There are three domains into which all living things can be classified.

Answer 29

These are Bacteria, Archaea, and Eukarya.

Question 30

domain Bacteria

Answer 30

The members of the domain Bacteria are common prokaryotic organisms found just about everywhere. While some of them do cause disease, the main function of a lot of bacteria is decomposition. They break down dead organisms to release nutrients back into the ecosystem. No nucleus. examples include: *E.coli, Streptococcus *

Question 31

Members of the domain Archaea are believed to be remnants of species alive during

Answer 31

Earth’s early years when conditions were much less hospitable than they are today. During that time, there was no oxygen in the atmosphere, and it was extremely hot.

Question 32

the domain Archaea

Answer 32

Today, Archaea live in extreme environments where other life cannot survive. Like Bacteria, Archaea are prokaryotic, lacking a true nucleus in their cells.

Question 33

An example of an Archaea is a species called a methanogen.

Answer 33

These organisms live in areas where methane gas is common (like it used to be billions of years ago). Methanogens can be found inside cow’s stomachs. The domain Archaea is not currently classified into kingdoms.

Question 34

The third domain into which organisms are classified is called the Eukarya.

Answer 34

These organisms are eukaryotic, meaning they have a membrane-bound nucleus. Members of this domain include animals, plants, fungi, and protists – basically everything other than the prokaryotic organisms.

Question 35

Every organism falls into one of the three domains. However, only the eukaryotic organisms can be classified into kingdoms. The four kingdoms of Eukaryotes are

Answer 35

he four kingdoms of Eukaryotes are the Animalia (animals), Plantae (plants), Fungi (fungus), and Protista (protozoans and algae). The kingdoms are classified using a hierarchy similar to that of the Linnaean system.

Question 36

What is a species

Answer 36

A species is defined as a group of individuals that can reproduce.

Question 37

What does it mean if two organisms are in the same genus

Answer 37

If two organisms are in the same genus, they also share the same domain, kingdom, phylum, class, order, and family.

Question 38

Who should scietifc names be written

Answer 38

It is also common protocol that, whenever one is typing a scientific name, it should be italicized, with the first letter of the genus capitalized. The species name is lowercase. A scientific name should be underlined when written by hand.

Question 39

When scientists find an organism they do not know, they use a tool called a ? to help them narrow down the options of what it could be. This is especially useful when examining species that look very much alike.

Answer 39

dichotomous key

Question 40

How to use a dichotomous key

Answer 40

The key is based on physical characteristics of an organism. It presents two options (the prefix “di” means “two”) of having or not having the characteristic. To use the key, a scientist makes choices based on the organism’s observed traits. Once enough traits have been narrowed down the scientist reaches a point where she cannot go any further and must select a species name.

Question 41

What is the relationship between Order and Family?

Answer 41

Organisms that are in the same Order are not necessarily in the same Family. However, organisms in the same Family are in the same Order.

Question 42

Linnaean classification is the basis for taxonomy. However, new ideas and technologies have improved the original system. Among the most important of these are:

Answer 42

* The theories of natural selection and evolution. These theories suggest that animals and plants which look similar might not share a common ancestor. Scientists used these new ideas to begin basing their classifications on more than superficial resemblances. * The discovery of genetics and DNA. This discovery allows scientists to better trace relationships among different species. * The invention of the microscope. Carolus Linnaeus did not know single-celled life forms exist. Microscopes make it possible for scientists to observe and describe organisms which can’t be seen by the naked eye.

Question 43

Why is taxonomy important?

Answer 43

It allows us to identify species, make important decisions about conservation, and discover new resources.

Question 44

Taxonomy is an important tool in helping to choose which habitats and species to conserve. Is the statement true or false?

Answer 44

This is true. Taxonomy is the process of identifying species and their place in the ecosystem. Thus, taxonomy is an important tool for conservation.