Modern Mammals
- Created by: ValentineDevil
- Created on: 08-04-19 17:42
View mindmap
- Modern Mammals
- Facts
- Decreasing diversity towards the latitudes
- 95 million fold difference in mass
- 3000m below to 5000m above sea level
- 5,500 species
- Mammalian Origin- early tetrapods
- Don't know what parental care was like- whether they milk-fed their young
- Therapsids
- Advanced Synapsids
- Legs positioned more vertically beneath bodies
- Fenestrae were larger than pelycosaurs
- Teeth and jaws more complex
- Cretaceous period was an extinction even for mammals
- 5 groups went extinct, leaving 3
- Diagnostics
- Hair
- even hair follicles
- Mammary glands
- Feeds offspring milk
- Sweat glands
- Sebaceous glands
- Four-chambered heart
- Diaphragm
- 3 ear bones
- Epiglottis
- lap in the throat that keeps food from entering the windpipe and the lungs.
- 2 testes, 2 ovaries, internal fertilisation
- Hair
- Classification
- Monotremes
- Reptile-like
- Meroblastic (contain food for developing embryo)
- Oviparous
- Single anogenital opening
- Mammal-like
- 3 ear bones
- Nourish offspring with milk
- 1 jaw bone
- Hair
- Other features
- Toothless
- Male platypus have venom
- Skeletal features and posture resemble early mammals and even reptiles
- Platypus have an intermediate gait between reptiles and mammals
- Reptile-like
- Marsupials
- 5 species: 4 echidnas, 1 platypus
- Split penis
- Marsupium (pouch)- not always present
- Major split in interrelationships between American and Australasian marsupials
- No flying marsupials
- Eutherian mammals
- 4 major clades
- Afrotheria
- Almost uniquely African species
- Some have left Africa, but majority still there- possibly because it was the origin of eutherian mammals
- Males have non-scrotal testes
- features of placenta
- Many have mobile proboscis
- Osteological characteristics of the ankle and patterns of dental eruption
- Afrosoricidae have a cloaca; golden moles have fossorial with no external ears; manatees are adapted for aquatic lifestyle
- Xenathra
- Was more diverse in the past
- South American group, most of the species are still only found in South America
- Related to Afrotheria
- Pilosa (sloths and anteaters)
- Cingulata (armadillos)
- Insectivores and herbivores
- Many are toothless
- Lumbar vertebrate with xenarthrous articulations
- Tympanic bone annular Septomaxilla in skull
- Pangolins
- •Superficially similar (no teeth, same diet) •Actually diverged from Carnivores •Unique keratinized scales
- Afrotheria
- 4 major clades
- Monotremes
- Facts
Comments
No comments have yet been made