Speciation and Extinction

First, the eyes... (Continuing from yesterday)

First, the eyes...

Broad Specific Taxonomic Group Humans are in... Domain Eukarya Kingdom Animalia Phylum Chordata Class Mammalia Order Primates Family Hominidae Genus Homo Species sapians Subspecies sapians

Taxonomy

Taxonomy allows us to make sense of the seemingly endless diversity we find in nature

Taxonomy allows us to make sense of the seemingly endless diversity we find in nature by organizing what we see into groups according to how they relate to each other

Three Taxon Statement Given three taxa, which two are more closely related to each other?

First find smallest sister taxa, then think outgroup

These are all the same.

Italics

Italics Genus capitalized

Homo sp.

H. sapiens

Pan sp.

Gorilla sp.

G. gorilla

G. gorilla Western Gorilla, Gorilla gorilla

Milvago sp.

tettigoniidae

Myrmotherula

Epinecrophylla Myrmotherula

Taxonomic name can tell you about relationship...

Not all traditional groups are clades Which are the dinosaurs?

Not all traditional groups are clades

You re welcome!

Speciation

Speciation Biological Species A group of organisms that can potentially interbreed and produce fertile offspring

Speciation Biological Species A group of organisms that can potentially interbreed and produce fertile offspring Speciation The formation of a new species

Speciation Biological Species A group of organisms that can potentially interbreed and produce fertile offspring Speciation The formation of a new species Gene pool A population s entire collection of genes and alleles Reproductive barrier Mechanism that prevents groups of organisms from sharing a gene pool

Prezygotic Barriers The prevention of two species combining zygotes

Postzygotic Barriers The selection against a hybrid offspring Jaglion Infertile

Allopatric Speciation

Allopatric Speciation Speciation by geographic separation Zones of endemism Dusky-throated Antshrike Saturnine Antshrike

Sympatric Speciation Speciation without geographic separation

Sympatric Speciation Speciation without geographic separation H. peruviana H. cantator

What s up with Ensatina?

Speciation may happen gradually

Or in fits and starts

In Punctuated Equilibrium

Extinction

Extinction Background extinction Gradual loss of species due to normal evolutionary process

Extinction Background extinction Gradual loss of species due to normal evolutionary process Mass extinctions Great number of species disappear in a relatively short amount of time. 5 occur in the fossil record.

Extinction Events: Chicxulub Crater

Test 2 on Thursday! Group activity: Make study tools! 7/16 = FIELD CLASS DAY at EDGEWOOD PARK Lab notebook Check Lab 11 (lab manual, lab notebook) 13 (lab notebook, plant lab) and Dissection Drawings