Speciation and Systematics APBioCh16and18

50 %
50 %
Information about Speciation and Systematics APBioCh16and18

Published on February 28, 2008

Author: MrDPMWest

Source: slideshare.net

The Origin of Species

Speciation I Requirements Isolation of populations Genetic divergence Speciation has seldom been observed in nature Allopatric speciation Sympatric speciation Ecological isolation Chromosomal aberrations Animals Plants

Requirements

Isolation of populations

Genetic divergence

Speciation has seldom been observed in nature

Allopatric speciation

Sympatric speciation

Ecological isolation

Chromosomal aberrations

Animals

Plants

Speciation II Types of speciation Divergent speciation Phyletic speciation Models of speciation Gradualism Punctuated equilibrium

Types of speciation

Divergent speciation

Phyletic speciation

Models of speciation

Gradualism

Punctuated equilibrium

Allopatric Speciation Single species (white mice); homogeneous habitat Geographical barrier (impassable river); isolated populations Genetic drift; genetic divergence; tan vs white mice Barrier removed (river dries up); mix but don’t interbreed (a) (b) (c) (d)

Sympatric Speciation Single species (white mice); homogeneous habitat (a) Climate change; two habitats; isolated because don’t mix (b) Environmental pressure to adapt; genetic divergence; tan vs white mice (c) Sufficient divergence; now different species (d)

Isolation Mechanisms Premating Geographical isolation (too far away/barrier) Ecological isolation (bird vs. fish) Temporal isolation (different mating seasons) Behavioral isolation (courtship and rituals) Mechanical incompatibility (tab A can’t fit into slot B) Postmating Gametic incompatibility (sperm can’t fertilize) Hybrid inviability Hybrid infertility

Premating

Geographical isolation (too far away/barrier)

Ecological isolation (bird vs. fish)

Temporal isolation (different mating seasons)

Behavioral isolation (courtship and rituals)

Mechanical incompatibility (tab A can’t fit into slot B)

Postmating

Gametic incompatibility (sperm can’t fertilize)

Hybrid inviability

Hybrid infertility

Speciation by Polyploidy Diploid Gamete Meiosis Diploid Gametes Viable Tetraploid Zygote Viable Diploid Gametes Haploid Gamete Viable Triploid Zygote Meiosis (fails) Triploids can’t do meiosis; No viable gametes. Tetraploid Plant Tetraploid Plant Diploid Plant Meiosis Fertilization Meiosis Fertilization

Interpreting an Evolutionary Tree Lines that don't reach the top represent extinct species. Forks represent speciation events. Each line represents a species. Lines that reach the top represent existing species. Steeper slope represents slow phenotypic change. More horizontal slope represents rapid phenotypic change.

Systematics: Seeking Order Amidst Diversity

Taxonomic Principles Taxonomic categories form an increasingly inclusive, nested hierarchy “ D id K ing P hillip C ame O ver F or G ood S ___" to remember categories Domain, Kingdom, phylum (animals and protists) or division (plants, fungi, bacteria, and plant-like protists), class, order, family, genus, and species Domain - most inclusive Species - least inclusive Scientific name— Genus and species

Taxonomic categories form an increasingly inclusive, nested hierarchy

“ D id K ing P hillip C ame O ver F or G ood S ___" to remember categories

Domain, Kingdom, phylum (animals and protists) or division (plants, fungi, bacteria, and plant-like protists), class, order, family, genus, and species

Domain - most inclusive

Species - least inclusive

Scientific name— Genus and species

Origins of Taxonomy Aristotle (384–322 B.C.) Simple classification Based on: Structural complexity Behavior Degree of development at birth Carolus Linnaeus (1707–1778) Based on resemblance to other life forms Established binomial nomenclature Charles Darwin (1809–1882) Categories reflect evolutionary relationship

Aristotle (384–322 B.C.)

Simple classification

Based on:

Structural complexity

Behavior

Degree of development at birth

Carolus Linnaeus (1707–1778)

Based on resemblance to other life forms

Established binomial nomenclature

Charles Darwin (1809–1882)

Categories reflect evolutionary relationship

The Changing Classification System Prior to 1970—two-kingdom system Plants and animals 1969—Roger Whittaker—five-kingdom system Monera, Protista, Fungi, Plantae, Animalia 1990—Carl Woese—three-domain system Bacteria, Archaea, Eukarya Discovered that kingdom Monera included two very distinct groups (Bacteria and Archaea) based on nucleotide sequences of ribosomal RNA

Prior to 1970—two-kingdom system

Plants and animals

1969—Roger Whittaker—five-kingdom system

Monera, Protista, Fungi, Plantae, Animalia

1990—Carl Woese—three-domain system

Bacteria, Archaea, Eukarya

Discovered that kingdom Monera included two very distinct groups (Bacteria and Archaea) based on nucleotide sequences of ribosomal RNA

Problems concerning classification of species The biological species concept defines species as “groups of interbreeding natural populations, which are reproductively isolated from other such groups” Cannot be applied to asexually reproducing organisms The phylogenetic species concept defines a species as “the smallest diagnosable group that contains all the descendants of a single common ancestor” Can be applied to sexually and asexually reproducing organisms May eventually replace the biological species concept

The biological species concept defines species as “groups of interbreeding natural populations, which are reproductively isolated from other such groups”

Cannot be applied to asexually reproducing organisms

The phylogenetic species concept defines a species as “the smallest diagnosable group that contains all the descendants of a single common ancestor”

Can be applied to sexually and asexually reproducing organisms

May eventually replace the biological species concept

Biodiversity How many species exist? 1.5 million species categorized Up to 30 million species may exist 7000 to 10,000 new species described/y Many classified species are becoming extinct as their habitats are destroyed

How many species exist?

1.5 million species categorized

Up to 30 million species may exist

7000 to 10,000 new species described/y

Many classified species are becoming extinct as their habitats are destroyed

Microscopic Structures Help to Classify Organisms (a) (b) (c) Bristles on a marine worm “ Teeth” on a snail’s radula Shape and surface features on a pollen grain

Similarity of Human and Chimp Chromosomes H = Human C = Chimp

Modern Criteria for Classification Anatomy - homologous structures Developmental stages - embryology Biochemical similarities - use of genetic information

Anatomy - homologous structures

Developmental stages - embryology

Biochemical similarities - use of genetic information

The Tree of Life

Representative Prokaryotes Vibrio cholerae of the domain Bacteria Methanococcus jannaschi of the domain Archaea

The Concept of Monophyly Monophyletic NOT Monophyletic (a) (b) (c) Reptiles not Monophyletic

Relatedness by DNA Sequences

The Origin of HIV Virus

The End

Add a comment

Related presentations

Related pages

Speciation and Systematics APBioCh16and18 - Technology

4. Allopatric Speciation Single species (white mice); homogeneous habitat Geographical barrier (impassable river); isolated populations Genetic drift ...
Read more

Speciation - Documents

Speciation. Describe and explain the different types of speciation. What is Speciation?. This is the formation of a new species. a species is a group of ...
Read more

Speciation - Documents

Speciation. 26. Key Concepts. Speciation occurs when populations of the same species become genetically isolated by lack of gene flow and then diverge from ...
Read more

EVOLUTION AND SYSTEMATICS SPECIES AND SPECIATION Ernst ...

EVOLUTION AND SYSTEMATICS SPECIES AND SPECIATION Ernst Mayr: "the greatest living evolutionary biologist“ -- S. J. Gould SPECIATION Speciation connects ...
Read more

Species Concepts And Speciation - Documents

Species Concepts and Speciation Mark McGinley Associate Professor Honors College and Department of Biological Sciences Texas Tech University
Read more

Species Concepts And Speciation - Documents

Species Concepts And Speciation Aug 29, 2014 Documents mark-mcginley. The present document can't read! Please download to view 50
Read more

Systematics - Education

1. Systematics and speciesJohn Wilkins 2. Lecture 1: ClassificationThe mind is finite in its powers of comprehension; theobjects, on the contrary, which ...
Read more

Systematics | LinkedIn

View 2983 Systematics posts, presentations, experts, and more. Get the professional knowledge you need on LinkedIn.
Read more

Systematics | LinkedIn

View 2930 Systematics posts, presentations, experts, and more. Get the professional knowledge you need on LinkedIn.
Read more