10.1 Species and Taxonomy

Question 1

Define classification:

Answer 1

the organisation of living organisms into groups based on accepted principles

Question 2

What defines a species?

Answer 2

Capability of breeding together to produce living, fertile offspring

Question 3

What are the two names in the binomial system?

Answer 3

1. The generic name denotes the genus a plant belongs to (similar to a surname)
2. The specific name denoted the species

Question 4

Rules that apply to the binomial system:

Answer 4

1. Names are in italics or underlined to indicate scientific nature
2. Generic name starts with a capital, specific name does not
3. if specific name is not known, ‘sp’ can be written

Question 5

How does courtship enable maximum chances for survival?

Answer 5

By enabling individuals to:

1. Recognise members of their own species
2. Identify a mate that is capable of breeding
3. Form a pair bond
4. Synchronise mating, to ensure highest chance of sperm and egg meeting
5. become able to breed by inducing a physiological state that allows it to occur

Question 6

The difference between classification and taxonomy:

Answer 6

Classification is the grouping of organisms whereas the theory and practice of biological classification is called taxonomy

Question 7

What are the two main types of biological classification?

Answer 7

1. Artificial classification

2. Phylogenetic classification

Question 8

What is Artificial Classification?

Answer 8

This involves dividing organisms according to differences that are useful at the time. Analogous characteristics that have the same function but different evolutionary origins

Question 9

What is Phylogenetic classification?

Answer 9

This is based on evolutionary relationships, and classifies species according to shared features derived from their ancestors. It also arranges groups into a hierarchy in which groups are contained within larger composite groups with no overlap. Phylogenetic classification is also partly based on homologous characteristics, e.g. the arm of a human and front leg of a horse

Question 10

What does Delicious King Philippa Can Order Fun Guys Seductively stand for?

Answer 10

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Question 11

What is a taxon?

Answer 11

Each group within a phylogenetic classification

Question 12

What are taxonomic ranks?

Answer 12

Heirarchical order in phylogenetic classification

Question 13

Three types of domain:

Answer 13

Bacteria, Archaea (prokaryotes) and Eukarya

Question 14

What features do bacteria have?

Answer 14

1. Single celled prokaryotes
2. Absence of membrane bound organelles
3. Unicellular
4. Ribosomes are smaller than in eukaryotes (70S)
5. Cell wall present and made of murein
6. Single loop of naked nucleic acid DNA but no histones

Question 15

How do Archaea differ from bacteria?

Answer 15

1. Their genes and protein synthesis are similar to eukaryotes
2. their membranes contain fatty acid chains attached to glycerol by ether linkages
3. No murein in cell walls
4. More complex form of RNA polymerase

Question 16

Main features of Eukarya:

Answer 16

1. Cells possess membrane bound organelle
2. Membranes containing fatty acids attached to glycerol by ester bonds
3. Not all possess cell walls, those that do have no murein
4. Ribosomes are larger than in Bacteria and Archaea (80S)

Question 17

Outline the main structure of the Eukarya domain:

Answer 17

Divided into four kingdoms: Protoctista, Fungi, Plantae, Animalia
Within each kingdom, the largest groups are known as phyla. Organisms in each phylum have bodies very different to organisms in other phylum. Diversity in each phylum allows class division. Each class is divided into orders of organisms that have additional features in common. Then we have families where the differences become less obvious and genera . Each genera is divided into species eventually. DKPCOFS

Question 18

What is phylogeny?

Answer 18

The evolutionary relationship between organisms. The phylogeny of an organism represents the evolutionary branch that led up to it. This information is usually represented in a phylogenetic tree with the oldest at the bottom and recent ones branching upwards.

Question 19

Why is there difficulty in defining species?

Answer 19

1. Species change and evolve over time
2. Within a species there can be considerable variation (e.g. artificial selection in dogs)
3. many species are extinct and have left no fossil record
4. some species rarely/never reproduce sexually
5. geographical isolation might mean members of the species never get the chance to interbreed
6. Some types of organisms are sterile