What makes us all mammals? • mammary glands, • secondary palate, • 3 middle ear bones, • brain—neocortex, • body temperature regulated by brain (endothermy) • hair 145 Compiled by Drs John Anderson & Norman Owen-Smith (Wits); Layout by Ditshego Madopi, Sarah de Villiers, Aneldi van Zyl & Waldo Swart Like the birds (Part 3), and the flowering plants (Part 2), the mammals (of which we are one) have evolved to prodigious diversity since the 5 th extinction (66 million years ago). That was when the dinosaurs disappeared, leaving a world of empty habitats to be filled. We explore our mammalian diversification & on-going extinction, both of which are tightly linked to climate change! Cold 20º C swing Hot Miocene Oligocene Eocene Paleocene Pleistocene Pliocene Cretaceous 0 10 20 30 40 50 60 55 65 5 15 25 35 45 80 100 125 Age (Ma) Epoch Late Early Paleogene Neogene Plei Period Climate change 5.3 2.6 Extinction Jurassic Biodiversity Diversity of Mammals Class:1 Orders: 28 Families: 153 Genera: 1,188 Species: 5,096 Part 4 Mammals 170 200 Triassic 250 Per- mian Myr ago 0 25 50 75 100 125 150 175 K-Pg Eutheria Prototheria Metatheria Theria Mesozoic Cenosozoic Jurassic Cretaceous Paleogene Neogene Q (Q: Quaternary) Placentalia Mammals GSA 2013 (Geological timescale); Reis et al 2012, Proc Roy Soc (timetree); Ripple et al 2015, Sci Adv (extinction) You might believe that you have nothing to do with extinction, but sadly our modern lifestyle impacts heavily on the world. However, our large brains can be used creatively to curb this extinction by making more informed decisions. Carnivora Perissodactyla Pholidota Rodentia Here we show animals from some 50 of the mammal families—grouped into their orders & ‘superorders’ The mammal timetree Ice-house 5 th 6 th 4 th 3 rd 5 th Extinction Extinction What makes us especially different amongst the mammals is our large brain wired for thought. Yet, in 3 historical waves of extinction, mankind has caused a severe decline in biodiversity. Today, we have both the power to further decimate life on Earth; or to protect it! P E M P O Insectivora Edentata Perissodactyla Cetaceae Primates Pholidota Artiodactyla Carnivora Rodentia Lagomorpha Afrotheria Marsupialia Monotremata Edentata Chiroptera Eulipotyphla (Insectivora) Dermoptera Artiodactyla Camelidae Camelidae Suidae Scandentia Hippopotamidae Hippopotamidae Suidae Late Cretaceous The world 75 million years ago Biodiversity & Ex tinction University Pretoria University Witswatersrand University Stellenbosch University Cape Town Cranefield College 6 th Extinction red = carnivores orange = omnivores green = herbivores Golden mole Afrotheria Dugong Aardvark Dassie Elephant shrew Tapir Beaver Lagomorpha Pika Dermoptera Flying lemur Armadillo Monotremata Platypus Echidna Pangolin Scandentia Tree shrew Sloth European mole Primates Bush baby Lemur Otter Wolf Cetaceae Orca Dolphin Sperm whale Chiroptera Fruit bat Leaf-nosed bat MacDonald (ed) 2009, Encycl. of Mammals (classification) Marsupial lion (Australia) Wooly mammoth (N. America) Malagasy pygmy hippo (Madagascar) Wave 1: Over 80% of all large mammals hunted to extinction; except in Africa What makes us so different? Though we are all genetically remarkably similar, we look extraordinarily different! We, over 5000 species, have adapted to live in just about every environment you can think of! Here are just three of those species Plio- cene 260 225 Eocene Optimum 56 Ma 66 Ma 126 Ma 131 Ma 134 Ma PETM mid-Cretaceous radiation of the birds & flowering plants Extinction Extinction pre 34 Ma Antarctica ca 34 Ma Antarctica Antarctic Glaciation 33.9 Ma Antarctic Thawing 23 Ma Antarctic Reglaciation 83.6 Ma 113 Ma 152 Ma Origin of mammals from mammal-like reptiles Extinction 6 th 3m 0.75m 0.7m Marsupialia Wombat Bandicoot Numbat Tasmanian devil See if you can think of the homes of each of the mammals shown! Air (flight) Water (rivers to oceans) Trees (forest to woodland) Terrestrial (above & beneath ground) Cities & villages Mammal habitats Wave 2: Out of Mid-East; as farmers from c.10,000 years ago Wave 1: Out of Africa; as hunter- gatherers from c.50,000 years ago Wave 3: Out of Europe; as industrial man from c.500 years ago Extinction caused by: •Population growth; we are now over 7 billion •Hunting; for sport & wild-meat •Farming; cultivation, domestication •Poaching; organised crime •Deforestation; & removal of other habitat •Climate change; our carbon footprint Hot-house 70,000 yrs ago 60,000 yrs ago 45,000 yrs ago 30,000 yrs ago 28,000 yrs ago 14,000 yrs ago Wave 1 Wave 2 Branches of timetree Imagine a very ancient tree of over 200-million-years old. And imagine still many more branches & twigs (representing families, genera & species) than are actually shown here. Mammal evolution & climate All living mammals, in around 150 families, evolved during a 20ºC cooling period from 50 million-years ago: from the Hot-house Earth of the early Eocene to the Ice-house Earth of today. If we reverse this trend far enough and fast enough, then every mammal species on Earth faces extinction! Big science As the accuracy of the timetree (genomics) & the climate curve improves, so our understanding of the inseperable tie between the two becomes clearer. (climate change possibly also played a role)