Classification (UNIT 2)

Question 1

Species

Answer 1

Similar to one another but different from members of other species.

Capable of breeding to produce living, fertile offspring.

Question 2

What do members of the same species have in common?

Answer 2

Similar genes so similar physical and biochemical properties. Similar patterns of development and similar immunological features and occupy same ECOLOGICAL NICHE.

Question 3

Naming Species- THE BINOMIAL SYSTEM

Answer 3

Two names.
UNIVERSAL
1st name- generic, denotes GENUS to which organism belongs. UPPERCASE

2nd name- specific name, denotes the SPECIES to which organism belongs (NEVER SHARED WITH ANOTHER SPECIES) LOWERCASE

PRINTED IN ITALICS or underlined if written.

Question 4

CLASSIFICATION

Answer 4

The grouping of organisms

Question 5

TAXONOMY

Answer 5

The theory and practice of biological classification.

Question 6

Two main forms of biological classification.

Answer 6

ARTIFICIAL CLASSIFICATION- divides organisms according to differences that are useful at the time. E.g. colour, size, number of legs, leaf shape etc.
NATURAL CLASSIFICATION-
-based on evolutionary relationships between organisms and their ancestors.
-Classifies species into groups using shared features derived from ancestors
-arranges the groups into a hierarchy.

Question 7

HOMOLOGOUS CHARACTERISTICS

Answer 7

SIMILAR EVOLUTIONARY ORIGINS.

Question 8

Order of classification of organisms.

Answer 8

KINGDOM
PHYLUM
CLASS
ORDER
FAMILY
GENUS
SPECIES

Question 9

PHYLOGENY

Answer 9

The evolutionary relationship between organisms

The phylogeny of an organism reflects the evolutionary branch that led up to it.

Question 10

Why are there difficulties in defining a species? (6)

Answer 10

• Species are not fixed but change and evolve over time. Some may develop into new species.
• Considerable variety within a species. eg dogs.
• Many species are extinct and most leave no fossil record.
• Some species rarely reproduce.
• Members of different groups of the same species may be isolated. May be classified as different species.
• Some species are sterile

Question 11

What are ANALOGOUS CHARACTERISTICS

Answer 11

Characteristics that have the same function but different evolutionary origins