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Why is biodiversity important?

Why is biodiversity important?


School: Towson University
Department: gender, women and sexuality studies
Course: Biodiversity
Professor: Christa partain
Term: Fall 2016
Tags: Biodiversity
Cost: 25
Name: Week 2 (Lecture 3 & 4) BIOL208
Description: Lecture 3: morphospecies, phylogentic tree, ancestral vs. derived traits Lecture 4: cladistics, cladistic terminology : plesiomorphy, symplesiomorphies, apomorphy, etc. monophyletic vs. paraphyletic vs. polyphyletic, outgroup.
Uploaded: 09/10/2016
3 Pages 41 Views 1 Unlocks

(9/6/16 - 9/8/16) Lecture 3 & 4

Why is biodiversity important?

Lecture 3: Review of Last week:

1. Why is biodiversity important?

We are dependent on crops, medicines, pharmaceuticals etc.

2. Plate tectonics

Shapes landscapes, temps, & ecosystems

Increases speciation/bio diversity

Cambrian period: 1st eukaryotes

Paleozoic era - oxygen revolution

How are phylogenetic trees constructed?

→ Paves way for multicellular life Don't forget about the age old question of What is a fake treatment given to the control group to mimic the experience of the experimental group?

Allows for aerobic respiration

Godwanna is disappearing & Pangea is forming

Production of new environments/nicheskus

This increases biodiversity (genetic diversity)

- Chronospecies

Pro: you can use fossils

Con: if you don't have fossils - you cannot analyze

What is the use of parsimony?

- Biological species

Con: leaves out non sexually reproducing organisms Don't forget about the age old question of What is the difference between civilizations and small scale societies?

- Biological clusters

con: not very practical for field biologists; cannot use it very easily

BSC (Biological Species Concept) vs PSC (Phylogenetic Species Concept)

Defines species as groups of interbreeding populations that are reproductively isolated

Species is a population/set of pop characterized by one or more shared/derived characteristics. Don't forget about the age old question of Who suggested that radiant energy is only emitted or absorbed in discrete quantities like small packages?

Hypothesis about patterns of Cannot be applied to allopatric populations

relationships among species BSC

Can only be applied to sexual species

- Phylogeny: evolutionary history of a group

I Darwin was (one of the) first creators of a tree

Can be applied to both sexual & asexual species




Systematics: If you want to learn more check out What is catering sales manager (csm)?

*** Biologists used to just use morphological traits to classify

We now have more tools to classify (DNA)

z organisms share a lot of traits 1. Composed of 1 or more cells 2. Carry out metabolism 3. Transfer energy via ATP 4. DNA as genetic code

Reconstruction & study of evolutionary relationships

- Phylogenetic tree → may or may not have time scale If you want to learn more check out Transformation is initiated by the recipient. the donor is not involved because it is dead. this is often how bacteria acquire antibacterial resistance. why?

Graphical representation of ancestry (pictured hypothesis of patterns/relations)

- Sister Taxa


Tax 2

Tax 3

Tax 4

Tax 5

Tax 6

(Taxon 1




More ancient

• How are phylogenetic trees constructed?

u Rates of evolution may vary

ools to construct:

1. Comparative anatomy 2. Comparative embryology 3. Fossil record If you want to learn more check out What are the some type of investigation?

4. biogeography 5. Molecular analysis Phylogenetic research is "dominated" by methods: Cladistics -

Analysis of shared & derived traits

- Use of Parsimony: hypothesis that uses the least amount of assumptions

Ancestral (Shared) vs. Derived characteristics —

"recent" trait Mammals --> hair (more recent trait)

"informative trait" Mammals --> lungs

(also present in

reptiles) Cladistics terminology:

• Plesiomorphy: ancestral characteristic Symplesiomorphies: shared ancestral states


• Apomorphy: derived characteristic

• Homoplasy: trait that could have come from convergent evolution

Lecture 4:


Cladistics: analysis of derived & shared traits in a group

Ancestral vs. Derived:

• Plesiomorphy = original ancestral trait

Shared plesiomorphy = symplesiomorphies

Apomorphy = derived characteristic


Shared apomorphy = synapomorphies

Homoplasy = does not tell us much about how animals are related; a trait that is not shared due to ancestry (convergent evolution)


Clade = aunts, uncles, cousins

→ = 1 clade

You, siblings, & parents

= 1 clade

OR the whole family = 1 clade

(clade) Monophyletic





Outgroup = the comparison group to the rest of the clade; has the least amount of


1 common ancestor & all descendants

Some, but not all descendants of a common ancestor

Does not include most recent ancestor

Notes/Discussion from the reading:

"Gregory, T. R., 2008. Understanding Evolutionary Trees. Evolution Education & Outreach, 1(2):121-137"

1. 2 points when it comes to phylogenetic literacy

a. It is critical to understand modern evolutionary concepts

b. It is in sufficiently common 2. There are no mainlines/hierarchies in phylogeny

Humans are not on top 3. Reading across the tips:

The order f the tips (on a tree) mean nothing. (make sure to pay attention to branching though. 4. Sibling vs. ancestor

chimps & humans; we didn't evolve from chimps & they aren't our ancestors - however we are related.

Molecular clocks - use proteins to make assumptions about substitutions & mutations

this allows us to se the latest ancestral divergence.

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