Lecture 15

Question 1

Carolus Linnaeus

Answer 1

• Systema Naturae 10th edition (1738) kickstarted
• Provides binomial nomenclature of genus species
• Biological classification reflects our knowledge of the relationships of organisms

Question 2

Why is biological classification so important?

Answer 2

A) Serves as file category to store information about a species. Allows comparisons with other area of the world
B) A better understanding of biodiversity and reduce mistaken identity
C) Facilitates communication between people in different fields
D) 5-20% of insects species have been described (most havent described their biology)

Question 3

Morphological Species Concept

Answer 3

• Most conventional way to describe insects
• Look at morphological characters to determine species
• Linnaeean, early taxonomists

Question 4

Biological Species Concept

Answer 4

• Species are groups of interbreeding natural populations that are reproductively isolated from other such groups
• Main criterion= interbreeding
• Operational difficulties: reproductive data is lacking, fossils don’t show anything, asexual taxa, hybridizing taxa

Question 5

Many different concepts

Answer 5

Morphological Species Concept
Biological Species Concept
Evolutionary Species Concept
Phylogenetic Species Concept
Cohesion Species Concept
*SO MANY BUT WHAT DO YOU DO?
TURN TO SYSTEMATICS

Question 6

Systematics

Answer 6

• The study of biodiversity and the relationships among groups of organisms (taxa)
• Made up of taxonomy and phylogenetics
• Taxonomy is the science of recognizing, describing and naming taxa and classifying them into groups
• Phylogenetics is the study of evolutionary history and relatedness
• These two ideas lead to species delimitation (study of species boundaries)

Question 7

Taxonomy vs Systematics

Answer 7

• Taxonomy refers to classification of organisms in bio while systematics refers to the study and classification of organisms for the determination of evolutionary relationship of organisms
• Taxonomy is a branch of systemics while systematics studies relationship of organisms
• Taxonomy is involved is the classification/naming of organisms while systematics is involved is classification/naming, cladistics, and phylogenetics
• Taxonomy does not deal with evolutionary history of organisms while systematics DOES
• Taxonomy can change with further study but systematics does not

Question 8

Multiple criteria for species determination

Answer 8

• Molecular characters (DNA comparison, genes, nucleotide alignment)
• Geographical characters(where in the world? more complicated these days since invasive and transport, some well distributed based on environmental needs)
• Morphology characters(what does the insect look like: body type, wings, legs, mouthparts, antennal types, reproductive organs)
• Reproduction
• Ecological characters (how it lives in environment, habitat, food, parasites, predators it has)
• Physiological characters(What does it look like, how does the inside work? Metabolism, muscles, chemistry, secretions)(cuticular hydrocarbons: prevents desiccation and mating cues)(hydrocarbons can be measured, antenna and sensilla basiconica)
• Ethological characters(behavior, territories, aggression, mate, recognition, courtship)

Question 9

Gradients and Polymorphism

Answer 9

• can cause a little disruption in identifying species

- Many color, size, and other physical differences but they could still be in the same species

Question 10

Coptotermes formosanus and Coptotermes gestroi (asian subterranean termite)

Answer 10

Looking at their locations, subterranean, they are very lines up based on latitude.
Always exceptions but they mainly stick to a specific latitude in the world

Question 11

Phylogenetics

Answer 11

Define: Study of evolutionary history and relatedness
A) enable us to find the origin, diversification, evolution, and biogeography (psat and present) of taxa
B) Provides us with better understanding of evolution and genomics
C) Phylogenetics trees are not restricted to only showing divergence between taxa. Also shows evolution of genes

Question 12

Phylogenetic Tree parts

Answer 12

The tips of each tree at the end are the taxa.
The most reent common ancestor is the node before taxa.
Nodes are where there is a split
Begins at the root.
Branch are between all the nodes and taxa.
Two taxa from one node are sister taxa.
Two groups of sister taxa that share a node and sister groups.
Ingroup is the group that have diverged more and outgroup is the group on the outsidethat has barely separated from root

Question 13

Groups of phylogenetic Trees

Answer 13

• Monophyletic group= ancestor and all descendants
• Paraphyletic group= ancestor but not all descendants
• Polyphyletic group= no ancestor, just descendants
• If give a tree, two taxa in the same clade will be mono, three taxa but does not include all taxa from the other clade means it is para, and two taxa in two different clades means it is poly

Question 14

Clasdistics

Answer 14

One approach to systematics and its goal is to infer phylogenies using patterns of similarity based on shared, evolutionary traits.

• Synapmorphies: Shared evolutionary novel features. Evidence that taxa are closely related
• Plesiomorphies: Evolutionary features are not shared and not closely related

Question 15

Characters

Answer 15

• Characters inform systematics and help classify taxa
• Characters are unique features that are useful for recognizing taxa
• We only want to group taxa based on characters that are homologous meaning that they share an origin in a common ancestor
• Homologous characters serve as synapomorphies that define evolutionary groups

Question 16

3 tests to determine homologous

Answer 16

1) Test of similarity- Is the character in the same location and develop the same way. Homologous do both
2) Test of congruence- Does the character serve as synapomorphy that defines a grouping that is supported by other character data. Homologous do
3) Test of conjunction- Does the character exhibit two states in the same individual. Homologous character don’t
EXAMPLE: Pierce sucking mouthparts? It checks out for the test of similarity, checks out for test of congruence, and checks out for test of conjuction. There are no hemipterans that exhibit more that one state of mouthparts so there are no two states in one individual.
Rostrums across Hemiptera are homologous and come from common ancestor

Question 17

Conjecture

Answer 17

Although some groups of taxa are well defined, relationships are based on much conjecture (how you interpret the character states)
How can you fix this, three ways to contruct tree

Question 18

Constructing Phylogenetic Trees

Answer 18

Parsimony: Minimize the number of changes across tree. Simplest model preferred
Likelihood models: Weighted substitutions, statistical analysis with confidence levels measured
Bayesian Approaches: Use many parameters and sample many tree in hopes of arriving at the correct one, dating analysis estimate ages of divergence

Question 19

Molecular Phylogenetics and the Genomics Age

Answer 19

1) Sequences of nucleotides or amino acid
a. mitochonrial genes (16S, COI, COII)
b. Ribosomal RNA (18S, ITS, 28S)
c Nuclear protein-coding genes
2) Sequencing approaches
a. Sanger Sequencing
b. Target enrichment of loci
c. Genome sequencing
d. Transcriptome Sequencing

Question 20

Is size a good measure for speciation?

Answer 20

NO, old colonies can have bigger insects

If they look similar but it is hard to tell then molecular phylogenetics is an option

Question 21

DNA barcoding

Answer 21

• DNA barcoding facilitates in matching of larvae with adults in identification of cryptic taxa.
• Help figure out important host associations
• Facilitates identification of food in molecular diet analysis