Classification

Question 1

Main principle in classification?

Answer 1

Groups must be monophyletic.

Question 2

Why are vernacular names preferred?

Answer 2

Based on the language of everyday life, so don’t need to memorise or pronounce the Latinised scientific name.

Can refer to the appearance of the organism, making it easier to remember.

Question 3

Problems with vernacular names?

Answer 3

Common names often have a very local distribution, so one organism in an area may have several names.

Common names can change with time.

A single common name may refer to more than one species.

Question 4

Advantages with scientific names?

Answer 4

Names are associated with groups, so allows for relationships to be drawn between species.

Clarity - each species will only have one scientific name.

Universal - scientific names are standardised and accepted universally.

Interspecific relationship - help understand the similarities and differences between species of the same genera.

Question 5

Define taxonomy?

Answer 5

Science of naming, describing and grouping living organisms.

Question 6

Define phylogenetics?

Answer 6

Study of evolutionary relationships between/within groups of organisms.

Question 7

Define systematics?

Answer 7

Inference of phylogenetic relationships between species.

Question 8

Define dichotomous?

Answer 8

Divides into 2 branches.

Question 9

Define monophyletic?

Answer 9

All share a common ancestor and contains all the descendants from a certain ancestor.

Question 10

What were early attempts at classification based on?

Answer 10

Intuition (Theophrastus 371BC) or morphology (Dioscorides 1st century)

Question 11

What did Gesner do?

Answer 11

Used more than one characteristic to classify. 16th century.

Question 12

What did John Locke do?

Answer 12

Talked about how it was possible to guess the primary essence by observing as much of the secondary essence as possible. 17th century.

Question 13

What were John Ray’s contributions?

Answer 13

Species definition: a group of individuals who share a unique combination of characteristics that can be replicated.

To preserve a species you need to grow plants from seeds to maintain sexual reproduction.

To classify you need to use as many characteristics as possible and allow for losses.

Don’t allow for one characteristic to become the priority.

His defined monocots have been shown to be monophyletic.

Question 14

Linnaeus’ contributions?

Answer 14

18th century.

“Without permanent names there can be no permanence of knowledge”

Used binomial names for each species.

However, chose reproduction as the priority which was a step backwards.

Question 15

Bentham and Hooker’s contributions?

Answer 15

19th century. Rejected Linnaeus and brought back Ray.

Used a hierarchical system. Defined the KPCOFGS system.

Question 16

Darwin’s contribution to classification?

Answer 16

Explained the apparent hierarchical pattern.

“Hidden bond of community of descent”

Question 17

Watson and Crick’s contribution to classification?

Answer 17

Discovered DNA structure in 1953. By 1970 it was possible to DNA sequence.

Darwin’s “hidden bond of community of descent” was revealed.

Question 18

How can a phylogeny be made more robust?

Answer 18

Using more characteristics and DNA sequencing.

Question 19

What else can be used for sequencing other than DNA?

Answer 19

Proteins, as these drive the cell’s behaviour and also evolve.

Question 20

Summary of the APG 1 Paper?

Answer 20

Angiosperm Phylogeny Group 1. 1998.

Added more accurate resolution to the phylogenetic tree at a family level.

Some of the proposals were completely unexpected when compared to a solely morphological tree, showing that morphology alone isn’t enough.

The molecular data did confirm that most of the families based on morphology were monophyletic - 73%.

Of the remaining 27%, 13% were amended in this classification, the other 14% were left unclassified.

Angiosperms were the first large group to be reclassified based on genetics.

No longer dicots and monocots as dicots weren’t monophyletic.

Question 21

What is the APG?

Answer 21

Angiosperm Phylogeny Group.

A classification system was published in 1998, 2003, 2009 and 2016.

Motivation were the deficiencies in the phylogeny due to non monophyletic groups.

Question 22

Why should be try to name and group all of the world’s organisms?

Answer 22

Identification and organising information - need a stable universal system in order to identify organisms.

Conservation - identify biodiversity hotspots to allocate resources to. Establish links between phylogenetic diversity and conservation strategies.

Crop breeding - identifying genes in wild relatives could be a quicker, more specific way of breeding new varieties.

Revealing evolutionary history

Support for theory of evolution

Understanding biogeography - can reveal patterns of distribution, migration and adaptation.

Predicting traits - can predict characters without needing to investigate each species

Searching for medicines - related species often produce similar chemicals and thus if a pharmaceutical molecule is found in one species, its relatives are worth investigating

Question 23

Example of how a phylogeny has changed?

Answer 23

The arthropod tree now links insects with crustaceans as a group of Pancrustacea, not with centipedes and milipedes (Myriapods) as was once thought.

Question 24

Example of a ring species?

Answer 24

Euphorbia in the Caribbean looks like a candidate for the first plant example.

Question 25

What is a ring species?

Answer 25

Connected series of neighbouring populations, each of which can interbreed with closely sited related populations, but for which there exist at least two “end” populations in the series, which are too distantly related to interbreed

Question 26

Example of a useful predictive trait?

Answer 26

Members of the potato family are often toxic and can be useful to pharmacology.

Question 27

Example of how searching for medicines is made easier with phylogenies?

Answer 27

Galantamine was originally extracted from snowdrops, but the closely related daffodils can produce more and make a better crop.

Used to show the development of Alzheimer’s disease.