Main Points
1) Defining “mammal” -- taxonomic perspective -- evolutionary perspective -- distinguishing features among classes within Subphylum Vertebrata
2) Discussion of Ceballos and Ehrlich 2009
3) Characteristics of mammals -- internal soft anatomy -- external anatomy -- will discuss skull in lab
Terms: cladogram, clade, amnion, homeothermy, derived character, ancestral/primitive character, convergence, homology, pelage, vibrissae, adaptive coloration (disruptive, aposematic, cryptic) 1 Some taxonomic perspective
Kingdom Animalia (~1,200,000 species)
2 Some taxonomic perspective
Kingdom Animalia (~1,200,000 species) Phylum Chordata (~63,000 species) -- dorsal hollow nerve cord (at least in embryos) -- notochord -- gill slits
3 Some taxonomic perspective
Kingdom Animalia (~1,200,000 species) Phylum Chordata (~63,000 species) -- dorsal hollow nerve cord (at least in embryos) -- notochord -- gill slits Subphylum Vertebrata (~60,000 species) -- backbone (vertebral column) -- braincase -- internal skeleton
4 5 6 How do vertebrates differ from each other?
• presence of amnion = fluid to protect egg or embryo
7 How do vertebrates differ from each other?
• two, three, or four-chambered heart
8 How do vertebrates differ from each other?
• homeothermy = near-constant body temperature
9 Convergence versus homology
fossorial afrosoricid (golden mole)
fossorial rodent (western pocket gopher)
fossorial marsupial (marsupial mole) 10 Convergence versus homology
sanguinivore (Desmodus)
nectarivore (Anoura)
frugivore (Chiroderma)
11 Sauropsida (split occurred ~200-250 MYA) 12 Some taxonomic perspective
Kingdom Animalia (~1,200,000 species) Phylum Chordata (~63,000 species) -- dorsal hollow nerve cord -- notochord -- gill slits Subphylum Vertebrata (~60,000 species) -- backbone -- braincase -- internal skeleton Class Mammalia (~5,400 species)
13 14 Roughly three years ago… olinguito (Bassaricyon neblina)
15 Roughly two years ago…
little black tapir (Tapirus kabomani)
16 Roughly 8 months ago…
skywalker hoolock gibbon (Hoolock tianxing)
17 The global distribution of newly discovered mammals (Ceballos and Ehrlich 2009) • roughly 1/10th of the world’s mammals discovered since 1993
• many of these “morphologically distinct”
18 Discussion Q: look at this figure. Can you put it into words?
19 Some internal characteristics of mammals
1) glandular skin: sweat glands
20 Some internal characteristics of mammals
1) glandular skin: sweat glands mammary glands (modified sweat glands)
21 Some internal characteristics of mammals
1) glandular skin: sweat glands mammary glands (modified sweat glands) scent and musk glands
22 Some internal characteristics of mammals
1) glandular skin: sweat glands mammary glands (modified sweat glands) scent and musk glands venom glands (not diagnostic)
23 Some internal characteristics of mammals
2) young develop in female’s uterus (excepting Prototherians)
24 Some internal characteristics of mammals
2) young develop in female’s uterus (excepting Prototherians)
3) large brain, relative to other vertebrates
25 Some internal characteristics of mammals
2) young develop in female’s uterus (excepting Prototherians)
3) large brain, relative to other vertebrates
4) well-developed facial muscles
26 Some external characteristics of mammals
1) hair: vibrissa (plural: vibrissae) guard hairs under hairs
27 Adaptive coloration
• Disruptive coloration
28 Adaptive coloration
• Aposematic coloration
29 Adaptive coloration
• Cryptic coloration
30