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Flashcards in B2a - classification Deck (13):
1

How are organisms classified(7)

Kingdom, phylum, class, order, family, genus, species

2

Why is it difficult to place organisms into distinct groups

the variety of life is a continuous spectrum which makes it difficult to place organisms into distinct groups

3

Explain the importance of classification of species

makes it easier to identify evolutionary and ecological relationships between animals and species

4

Describe the systems of classifying organisms(6)

Natural
 -based on evolutionary links
-organisms with common ancestry grouped together

Artificial
-based on visible features
-makes a group of organisms easier to identif

5

What has the use of DNA sequencing information led to? (2)

biologists realised that some organisms are more closely related than originally thought

leads to reclassification of some organisms to form more accurate links between organisms

6

Why do systems of classification change over time(2)

to form more accurate links between organisms as biologists learn more about organisms(e.g. their genetics and the sequence of their DNA bases)
-through which we realise that some organisms are more closely related than originally thought

7

How can evolutionary relationships between organisms be displayed

using evolutionary trees

8

How can the evolutionary relationships of organisms in a group be modelled(3)

by analysing multiple characteristics and looking for similarities and differences

the more characteristics analysed, the more accurate the evolutionary tree model becomes

ICT has facilitated analysing multiple characteristics

9

Define the term species

a group of organisms which are capable of interbreeding to produce fertile offspring

10

Describe the binomial system of naming species(4)

each species is known by a 2 ­part name
-first name is the genus
-2nd name identifies a single species

it is the international basis of naming species and prevents confusion

11

Explain some of the problems of classifying organisms into species (8)

Hybrids
-when members of two species interbreed
-are infertile, so cannot be classed as a species

Organisms that only reproduce asexually(e.g. bacteria)
-do not interbreed - does not fit the definition of a species
- biologists classify them as diff species, based on characteristics

Evolution is a continuous process
-organisms are slowly changing and can eventually become new species

12

Describe closely related species(2)

Shares a relatively recent common ancestor

may have different features if they live in different types of habitats

13

How can similarities and differences between species be explained(2)

Ecological relationships
-e.g. similarities between different organisms that live in the same habitat

Evolutionary relationships
-e.g. relations between animals that live in different habitats