Lecture 15 Flashcards
Carolus Linnaeus
- Systema Naturae 10th edition (1738) kickstarted
- Provides binomial nomenclature of genus species
- Biological classification reflects our knowledge of the relationships of organisms
Why is biological classification so important?
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)
Morphological Species Concept
- Most conventional way to describe insects
- Look at morphological characters to determine species
- Linnaeean, early taxonomists
Biological Species Concept
- 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
Many different concepts
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
Systematics
- 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)
Taxonomy vs Systematics
- 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
Multiple criteria for species determination
- 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)
Gradients and Polymorphism
- can cause a little disruption in identifying species
- Many color, size, and other physical differences but they could still be in the same species
Coptotermes formosanus and Coptotermes gestroi (asian subterranean termite)
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
Phylogenetics
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
Phylogenetic Tree parts
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
Groups of phylogenetic Trees
- 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
Clasdistics
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
Characters
- 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
