classification

Question 1

Taxonomy

Answer 1

Science of classifying organisms

Question 2

Binomial Nomenclature

Answer 2

Two- word system that is used to name organisms

Question 3

Reasons why we classify

Answer 3

1. Enables the organisation of organisms into groups which lets the scientists see the information about the organisms and the relationships between them.
2. makes it easier for ALL scientists to communicate information about the organism as the scientific names are in latin

Question 4

Some of the benefits of classification include:

Answer 4

• Personal Safety
• Quarantine
• Medicine
• Conservation
• Forensics

Question 5

Benefits of classification for Personal Safety?

Answer 5

– It is critical to identify the difference between poisonous and harmless, pests or carriers of disease

Question 6

Benefits of classification for Quarantine

Answer 6

know which animals or plants are banned from entering our country.

Question 7

Benefits of classification for Medicine

Answer 7

identify infectious bacteria or fungi so can prescribe correct drugs.

Question 8

Benefits of classification for

Answer 8

recognize endangered species so they can be protected and their habitats preserved

Question 9

Benefits of classification for

Answer 9

to identify plant or animal material to be used in legal matters.

Question 10

All living things have certain characteristics in common which they..

Answer 10

o Collect or make Energy for immediate or later use.
o Respond to stimuli or changes in its environment
o Grow as it gets older
o Reproduces
o Passes on Genetic information
o Produces wastes
o Are made from Cells

Question 11

Identification of an organism can be based on a study of:

Answer 11

1. A whole Specimen
2. Part of a Specimen
    feathers, hair, teeth, bones, shells
3. Fossils
4. Microscopic Fragments
    cells, pollen grains, scales, hair.
5. Genetic material
    analysis of DNA
6. Indirect evidence
    tracks, burrows, nests, scratchings, droppings

Question 12

Taxonomists look at:

Answer 12

1. Homologous structures
2. Analogous structure
3. Chemical tests
4. Life studies
5. Embryology

Question 13

Homologous structures

Answer 13

Structures that have a very similar structure but may Look different in different organisms

Question 14

Analogous structure

Answer 14

Structures in different organisms that have looked similar, have similar functions

Question 15

Chemical tests

Answer 15

o analyse blood to find similarities or differences.
o If they are related the blood will show similarities in molecular composition.
o The more common chemicals – the more closely related they are.

Question 16

Life studies

Answer 16

o involves studying the stages in life of an organism.
o E.g. ferns and flowering plants
o reproduce differently

Question 17

Embryology

Answer 17

o the study of embryo development.
o If embryos are similar in appearance at some stage, then the organisms are related.
o The longer time that the embryos are similar, the more closely related they are.
o E.g. all vertebrate embryos start with gill slits and a tail; as they develop they start to differ.

Question 18

Levels of Classification

Answer 18

• These levels start at a few very large domains, then groups or kingdoms and progresses down to many very small groups (species).

Question 19

All living things are now classified into 3 Domains:

Answer 19

o Bacteria
o Archaea
o Eukaryotes

Question 20

Eubacteria Domain

Answer 20

o All bacteria are prokaryotic
o Cell walls made of peptidoglycan (which means the cell wall will stain a purple colour in a Gram stain) so they are classified as gram-positive bacteria
o Reproduce by binary fission
o Some are photosynthetic – make own food
o Some are chemosynthetic – nitrogen-fixing and sulphur-oxidising bacteria

Question 21

Archaea Domain - Extremophiles

Answer 21

they thrive in extreme environments, such as
o Salt lakes - halophiles
o Acidic water
o Alkaline water
o Oxygen lacking marshes & swamps – methanogens (produce methane)
o Hot springs – thermophiles
Cell walls without peptidoglycan (which means the cell wall will not hold the stain making it a pink colour) so they are classified as gram negative bacteria and they are pathogenic.

Question 22

Eukaryotes

Answer 22

Cells that have a membrane around the nucleus and contain organelles which have a special function.

Question 23

All Eukaryotes are classified into 4 Kingdoms

Answer 23

o Plants
o Fungi
o Protists
o Animals

Question 24

Phylum

Answer 24

• The Phylum is the next level following kingdom in the classification of living things. It is an attempt to find some kind of physical similarities among organisms within a kingdom.

Question 25

Class

Answer 25

• Organisms of a Class have even more in common than those in an entire phylum.

Question 26

Order

Answer 26

• Organisms in each class are further broken down into Order.
• A taxonomy key is used to determine to which order an organism belongs.

Question 27

Family

Answer 27

• Orders are divided into Families.
• Organisms within a family have more in common than with organisms in any classification level above it.
• Because they share so much in common, organisms of a family are said to be related to each other.

Question 28

Genus

Answer 28

• The Genus classification is very specific so there are fewer organisms within each one.
• For this reason there are a lot of different genera among both animals and plants.
• When using taxonomy to name an organism, the genus is used to determine the first part of its two-part name.

Question 29

Species

Answer 29

• Species are as specific as you can get.
• It is the lowest and most strict level of classification of living things.
• The main criterion for an organism to be placed in a particular species is the ability to breed with other organisms of that same species to produce fertile offspring.
• The species of an organism determines the second part of its two-part name.

Question 30

Kingdom
Phylum
Class
Order
Family
Genus
Species

Answer 30

Keep
Pond
Clean
Or
Froggy
Gets
Sick

Question 31

Naming of Organisms

Answer 31

o Scientific names consist of two parts, the first name corresponds to the Genus of the animal (begins with a capital letter) and the second name is the species of the organism (begins with a small letter).
o E.g. Cervus elephus (red deer)

Question 32

Species can be defined in different ways:

Answer 32

o Structurally similar.
o Capable of Interbreeding under natural conditions, and producing Viable ( are capable of living) and Fertile Off Spring.
o Number and shape of Chromosomes
o Molecular analysis (Dna)

Question 33

Hybrids

Answer 33

o are not a species

Question 34

Viruses

Answer 34

o Viruses do NOT fit into the five kingdom classification system of the three domain system.
o They are not cellular.
o Viruses are made of a simple PROTEIN COAT surrounding a piece of viral genetic material.
o Viruses cannot metabolize or respond to stimuli.
o On their own they can do nothing until they enter a living Host cell.
o They form PARASITIC relationships with living organisms; the virus benefits at the expense of the living organism.
o Outside of the host, they act as non-living chemicals - VIROIDS.

Question 35

Viruses do not have

Answer 35

o A cellular structure
o A membrane
o Cytoplasm or other organelles

Question 36

Viruses have

Answer 36

o Outer protein coat (capsid)
o (DNA or RNA). As they have genetic material, they can mutate and evolve.
o The ability to reproduce, but only with a host’s help

Question 37

Viroids

Answer 37

o are virus particles as it exists outside the host cell,
o They may be regarded as the EXTRACELLULAR PHASE of the virus – they are INERT (not active)
o they are exactly analogous to “spacecraft” in that they take viral genomes from cell to cell, and they protect the genome in inhospitable environments in which the virus cannot replicate.

Question 38

The Life Cycle of a Virus

Answer 38

1. Viruses first latch onto a cell.
2. Virus then invades the cell by injecting their DNA into the ‘host cell’.
3. The cell doesn’t recognize the DNA as being foreign and so the host cell starts manufacturing many new virus parts according to the virus’ DNA.
4. These virus parts then assemble inside the host cell.
5. When they are fully assembled they burst out of the host cell killing it (lysis (breaking)), and then they go off to infect more host cells

Question 39

Antibiotics

Answer 39

o antibiotics have no effect on a virus.
o Most antibiotics interfere with the reproduction of bacteria, hindering their creation of new genetic instructions or new cell walls. Because viruses do not carry out their own biochemical reactions, antibiotics do not affect them.

Question 40

Immunisation

Answer 40

o Immunizations work by pre-infecting the body so it knows how to produce the right antibodies as soon as the virus starts reproducing.
o Because viruses reproduce so quickly and so often, they can often change slightly. Sometimes, mistakes are made to their genetic instructions.
o These changes might alter the protein coat slightly, so one year’s batch of vaccine might not be as effective against the same type of virus next year.

Question 41

Vaccine

Answer 41

o A vaccine is a weakened form of a disease.
o It is either a killed form of the disease, or it is a similar but less virulent strain.
o Once inside your body your immune system mounts the same defence, but because the disease is different or weaker you get few or no symptoms of the disease.
o Now, when the real disease invades your body, your body is able to eliminate it immediately.