Speciation - Macroevolution

What is a Species?

Morphological species Problems?

Variable Morphology Grown in water Grown on land

Figure 14.3a

What is a Species? Biological Species Concept –Population –Interbreed –Fertile offspring –Reproductive isolation

Reproductive Isolation

Isolating Mechanisms Prezygotic isolation Postzygotic isolation

Figure 14.4

Prezygotic Isolation Behavioral Isolation

Prezygotic Isolation Temporal Isolation

Prezygotic Isolation Ecological Isolation

Prezygotic Isolation Mechanical Isolation

Prezygotic Isolation Gametic Mortality

Postzygotic Mechanisms Hybrid inviability Hybrid sterility Hybrid breakdown

Figure 14.3D

Mechanisms of Speciation Allopatric speciation –Barrier prevents gene flow Sympatric speciation –W/in home range

Figure 14.7

Allopatric Speciation A. harrisiA. leucurus Figure 14.4

–Isolation in Death Valley New species of pupfish Figure 14.5B A pupfish Allopatric Speciation

Figure 14.9

Sympatric Speciation Polyploidy Change in chromosome number (3n, 4n, etc.) Parent species Meiotic error Self- fertilization Offspring may be viable and self-fertile Zygote Unreduced diploid gametes 2n = 6 Diploid 4n = 12 Tetraploid O. gigas O. lamarckiana

AABB AB AA BB DD ABD AA BB DD   Triticum monococcum (14 chromosomes) Wild Triticum (14 chromosomes) Sterile hybrid (14 chromosomes) Meiotic error and self-fertilization T.turgidum Emmer wheat (28 chromosomes) T.tauschii (wild) (14 chromosomes) Sterile hybrid (21 chromosomes) Meiotic error and self-fertilization T.aestivum Bread wheat (42 chromosomes) Possible Evolution of Wheat Figure 14.7B

Models for Speciation Gradual change model –Small changes over time Punctuation model –Brief period near divergence

Figure 14.12

How have complex structures evolved? Many stages From simpler versions w/ the same basic function Figure Light-sensitive cells Light-sensitive cells Fluid-filled cavity Transparent protective tissue (cornea) Cornea Layer of light-sensitive cells (retina) Nerve fibers Nerve fibers Optic nerve Optic nerve Optic nerve Eyecup Retina Lens Patch of light- sensitive cells Eyecup Simple pinhole camera-type eye Eye with primitive lens Complex camera-type eye LimpetAbaloneNautilusMarine snailSquid

Changes in development Timing and rate of growth How? Figure 14.12A

Figure 14.12B Chimpanzee fetusChimpanzee adult Human fetusHuman adult

Stephen Jay Gould (evolutionary biologist) Mickey Mouse “evolved”  Copyright Disney Enterprises, Inc. Mickey?

Evolutionary trends do not mean that evolution is goal directed Figure Hippidion and other genera Nannippus Neohipparion Hipparion Sinohippus Megahippus Archaeohippus Callippus Hypohippus Anchitherium Miohippus Parahippus Paleotherium Propalaeotherium Pachynolophus Orohippus Epihippus Equus Pliohippus Merychippus Mesohippus Hyracotherium Grazers Browsers EOCENE OLIGOCENE MIOCENE PLIOCENE E RECENT PLEISTOCEN End Goal? No!

Rocks and fossils –Radiometric dating radioactive isotopes Geologic Record

Figure 14.17

Figure 14.16

Table 15.1

Impact on macroevolution? Edge of one plate being pushed over edge of neighboring plate (zones of violent geologic events) Antarctic Plate Australian Plate Split developing Indian Plate Eurasian Plate North American Plate South American Plate Nazca Plate Pacific Plate Arabian Plate African Plate Figure 15.3A Continental drift Figure 15.3B Millions of years ago Paleozoic Mesozoic Cenozoic North America Eurasia Africa South America India Antarctica Australia Laurasia Gondwana Pangaea

Continental drift Volcanoes and earthquakes San Andreas Fault North American Plate San Francisco Santa Cruz Los Angeles Pacific Plate California Figure 15.4A, B

Figure 14.18

Permian and Cretaceous periods –Dinosaurs? Mass extinctions

Adaptive Radiation Burst of divergence Single lineage gives rise to many new species New species fill vacant adaptive zone

Hawaiian Islands Adaptive radiations: –Honeycreepers –Fruit flies (Drosophila) - 40% of fruit fly species are found in Hawaii

Hawaiian Honeycreepers FOUNDER SPECIES Figure 18.7 Page 297

Classifying Diversity Taxonomy Phylogeny –Homologous structures and molecular sequences –Evidence of common ancestry

Figure 15.6 Ancestry? Or Convergent evolution? PHYLOGENY

Systematics –Connects classification w/ evolution Binomial –Genus –Species Phylogeny Species Genus Family Order Class Phylum Kingdom Domain Felis catus Felis Felidae Carnivora Mammalia Chordata Animalia Eukarya

Species Felis catus (domestic cat) Mephitis mephitis (striped skunk) Lutra lutra (European otter) Canis familiaris (domestic dog) Canis lupus (wolf) Genus Family Order Felis Felidae Carnivora Mustelidae Mephitis Lutra Canis Canidae Figure 15.7B Phylogenetic tree PHYLOGENY

Figure 14.24

–The simplest (most parsimonious) hypothesis Figure 15.8B Lizards Snakes CrocodilesBirds Common reptilian ancestor CLADOGRAMS