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• Classification can be complex and somewhat subjective.
• Taxon placement can be tricky, with animals like the platypus posing challenges.
• Taxonomists attempt to classify animals based on phenotypic variations.
• Phenotype refers to physical characteristics.
• Genotypes, which are genetic characteristics, are also now considered in classification.
• Phylogenies are created to understand evolutionary relationships.
• Phylogenetics studies the evolutionary history of life.

Phylogenetic Trees

• The goal is to create tree-like diagrams showing connections.
• Branching patterns represent the believed relationships between organisms.
• Cladograms are similar and organize organisms by ancestry.
• Characteristics may or may not indicate relatedness.
• Physical traits are not always due to relatedness.

Homoplasies

• These are superficially homologous features independently acquired.
• They are not due to relatedness, but arise for other reasons.
• Dolphin's torpedo shape is for hydrodynamics, an example of convergent evolution also seen in sharks.

Homologous Structures

• These structures are derived from recent common ancestors.
• Relatedness is shown through evolution favoring useful traits.
• Characteristics are inherent through evolutionary processes.
• Plesiomorphic characteristics: Subcategory of homology
• Represent characteristics present in ancestors and still present today, include vertebrae.
• Synaptomorphic characteristics: Unique to a specific group, for example, hair in mammals.

Traits

• Some can be both plesiomorphic and synaptomorphic depending on the context.

Evolutionary Tree

• The actual "real" one is unknown.

Phenetics

• Considers domesticated and wild cats and vertically lists them.
• Became popular in the 1980s with increased computer accessibility.
• Massive data amounts could be automatically inputted/sorted.

Downside of Phenetics Features

• Computers cannot discern homoplasies from homologous ones because characteristics are phenotypes.
• This was the first and outdated system as of the late 1800's

Cladistics

• Aims to eliminate homoplasies using phylogenetic systematics.
• Took about 20 years to gain acceptance.
• Emphasizes genealogy and examines the history of organisms.
• Flaws in phenetics are removed by eliminating homoplasies.

Evolutionary Systematics

• Focuses on homologies.
• Studies organism diversity and related evolutionary processes.
• Emphasizes divergence extent over genealogy.
• Softens lines on the taxonomy tree, example being Whales evolved from artiodactyls (deer).

Parsimony

• Explains this concept like "Simplest answer must be the right one"
• Mammals are less diverse than many groups.

Mammals

• New species are discovered annually, it fluctuates constantly
• Currently 6,753 species living and extinct, 6640 living species
• Species is the only fixed classification; everything above it (family, order, class, kingdom) is subjective.
• Relatedness is difficult to sort.
• The current naming system is binomial nomenclature, from Linnaeus 1758.

Nomenclature

• Binomial nomenclature contains: Genus, epithet, and authority,
• The authority describes the species.
• The whole thing together is a species ex. Homosapian Linnaeus.
• Linnaeus named Homosapians in 1758.

Why Latin?

• It's universal, a dead language so no one gets an advantage.
• Latin or Latinized words with distinctive gender fit the genus.
• The epithet must match the genus gender.
• The ICZN regulates zoological nomenclature.
• It was founded in 1895 to create, publish, and revise naming rules.
• To describe a new species: Name must be Latinized, description given, holotype needed

Holotype

• A single specimen, designated, and description given
• Example of this being splitting African elephants into Asian and African
• Linnaeus-named species use to the original specimen to determine species name
• The syntypes, series, and neotype, a replacement if the old holotype is lost.
• Lectotypes, paratypes, and topotypes are also types recorded.
• Determining criteria include geographic range and differential diagnosis.

Species Description

• It must include measurements, remarks, a list of examined specimens, and distinguishing features
• The list cannot be anonymous and cannot be a synonym or homonym.
• Scientific names are fixed but can be changed for several reasons:
  • Homonym: One species turns out to be two. Holotype used to decide original name.
  • Reorganization reasons: Includes old and new world names.
  • Correct grammar.
  • Reorganization leading to homonym is a problem
• Example of this being Moving mountain lion/puma/cougar, Puma concolor, to Felis concolor because of shared traits.

Marsupials

• Monotremes: Have 2 extant families and are still alive
  • Ornithorhynchidae:
    • Platypus: George Shaw described the platypus as 'extraordinary'.
  • Tachyglossidae:
    • Echidna: It was thought to be a joke
• Both species are found in Australia and are Oviparous (egg layer).
• Monotremes: Have reptilian features and are not ancestral to therians
• They have an incomplete right atrium and lack a corpus callosum.
  • Lack of bridge of neural tissue connection - needed for complex thought. Which is also found in marsupials.
• Reptilian pectoral girdle and a cloaca, and threadlike reptilian sperm ('no head').
• Homeothermic: And have a challenging time maintaining body temp.
• Chromosomes: Mammals have macrochromosomes, birds/reptiles/fish have microchromosomes, and monotremes have both and have epipubic bones.

Platypus

-Edentate:Have no teeth,

• Immature platypus have teeth in gums that dissolve.
• Babies have an egg tooth.
• Males have a horn-like spur on rear ankles.
• On the duckbill platypus, there is a venom gland associated with that spur.
• Like birds, only the left side of the female reproduction system is functional for this reason.
• Lay cledoic egg a protective shell
• Also have eggs but are meroblastic which opposes holoblastic
• Yolk broken along cell evenly
• They are Nitifugous - "Nest fugitive” which translates to
• “Don't return to the nest and to leave nest quickly”
• Also can be Nidicolous
• Stay in the nest for a long time.
• Mammary glands do not have nipples, excreted from skin and suckled from hair tuffs.
• The milk has high iron because young are unable to store it like other mammals can and are semi-aquatic omnivore

Metatherians

• Suborder: Marsupilia (marsupials)
• Marsupials evolved in South America.
• Primarily found in North and South America, and Australia.
• Moved to Australia during Pangea.
• Marsupials colonized Australia in isolation, with no eutherian competition.
• Make up over 50% of mammals in Australia but 6% worldwide.

Characteristics

• In not all groups the Marsupium is present.
• Pouches can open to the front (kangaroo) or back (wombat).
• Testes are anterior to the penis in males
• They Have a lot of teeth as well as epubic bones
• More teeth compared to eutherians such as 5/4, 1/1, 3/3, 4/4 = 50 for marsupials, verses ,3/3 (incisors),1/1 (canines),4/4 (premolars),3/3 (molars) =44 eutherians
• Structurally Reproduction is most notable difference between marsupials and eutherians

TLDR Reproductive System

• Pregnancy lasts around 2 weeks
• Baby is short and undeveloped with eyes, ears, and arms to crawl to the pouch.
• Lactation is extremely long taking long to make, but has short pregnancy for termination.
• Kangaroos can have 3 joeys in different cycles at the same time. 1 in eutero, developing in pouch, or outside the pouch.
• No marsupial weighs more than 1% mom's body weight at birth.
• Conservative body plan because birth requires so much.
• Decent size difference and no carnivorous marsupials

Bones

• Single dentary bone that articulates with the cranium and squamosal bone - Jugal involved in metatheriums.
• Has Three middle ear bones.
  • Malleus, incus, and stapes (stirrup) attached to coplia
• All mammals have 3 middle ear bones behind the eardrum
• Some consider the 2 auxipital condiles. - Separate joints allow side-to-side/up-down movement.
• Hair at some point in life and mammary glands for soft anatomy. -4 chamber heart w/left aortic arch. - Crocodillians/birds have a right aortic arch.
• Enuculate Erythrocytes - No nucleus
• All mammals have have 1 lower jaw bone - the dentary bone. The osicles include malleus, incus and stapes
• Muscular diaphragm helps separate cavities.
• Also contains 2 articulating occipital condyles (not "unique")
• Soft anatomy includes
  • Mammary glands, 4 chambered heart, Enuculated,and muscular diaphragm

Dental

• Dental (muscle tissue between gut and hearts, compresses and expands lung cavity) -Dentition include tribosphenic molar - 3 point molars
• Quadritubercular Molar found in mammals today V-shape = zalambdont tooth while W-shape= dilambdont tooth
• Teetrh can be Heterodont (teeth types), Herbivore, Carnivore, and Omnivore
• Diphyodont dentition = 2 sets of teeth in life while Polyphyodont = multiple sets
• Crown = above gums while Root = below gums

Teeth Types

• Opened: Grows throughout life, such as beavers/mice
• Closed: Determinate and stops growing.
• Hypsodont - high crowned that gets easily worned of such as found in herbivores
• Brachyodont - low crowned and relatively small teeth
• Bunodont - rounded crushing tooth such as Otters, racoons, and humans
• Lophodont cusps on grinders such as found in herbivores
• Selonodont curs form crescents and are found also in herbivores
• Sectorial dentition - = 4 upper premolar & first lower molar pair of scissors
• 4 types of teeth:
  • Incisor, Canines, Premolars, and Molars

Hair

• Dead material - made of keratin with medula in thhe center
• Hollw and solid with Air pockets
• Highly packed cells create cortex hair shaft
• Scale-pattern is on the scale of the outer edge
• Insulation and original function Pelage are found Pelage = coat of haiand pelage is:
• Insulation is its original function Blubber are found in whales for pelage Large fatsize with Protective coloration - camouflage Defense also is protection: Barbs (hedgehog and porcupines) Plates (anteaters) Creates consistent colorin the Belly by using Countershading
• Alert coloration:"Warning" for skunks
• Albino (Genetic)
  • Melanocortin 1 receptor defects Leucism (Lacking pigment)
  • Not quite albino
• Contains Hairs that have Vibissaes Tactile for Active & passive Protection and insulation Body hair Hair on neck standing up and can have erectile tissue

Guard hairs

• Spines (porcupine)
• Bristles (mane of lion or horse) Awns - overfur Underhairs include
• Wool, the shor & fine (underfur),Velli - embryonic hair
• Molts = shedding of hair
  • Seasonal molt

Bats

• 1000 species, the 2 most successful groups
• Distributed worldwidebut are Absent in polar regions, isolated islands, and mountaintop regions
• Group of things that do similar things in similar ways - not based on relatedness. Guilds are ecological roles.
• Bats are taxonomicMess and genus and species mostly sorted out

Taxonomy

- Upper taxonomy is often debated.
- Early biologist classification was on physical characteristics.

-Original taxonomy

• Order: Chiroptera andLiterally means hand wing and has 2 suborders Megachiroptera and areOld world fruitbats example, flying foxes Microchiroptera Changed to Yangchiroptera and Yingchiroptera. Changed again Old world fruit bats are pteropiformes Significant convergent evolution Different diets: Carnivorous Bats: Frogs, birds, lizards, other bats diets Insectivores: Control insect populations Bats in Texas save that saves farmers 3 billion in pesticides Mosquitos, corn ear worm, spotted cucumber beetles Nectar & Pollen: Dip tongue into feeder while flying by which hitrun method Long bristles tongues Tequila farms relies on Bats Fruit bats: Plants evolved fruit for target species Bats better than birds at seed disposal Seeds will pass and get deposited Bird digestive system very quickly

Bat

• Diets for fish Catching methods fits catching frog or lizard different method Echolocation does not penetrate water, Because of water tension, where fish are causes a rise in the water. Only 3 species of fish bats Massive feetclaws. Tiny Vampire bats: Only 3 species 2 species feed on mammal blood,one that feeds on birds Angled incisors are what bats use to draw blood Very small Nips at animals to draw blood. Licks the wound. Saliva has properties that prevent wounds from congealing ,but they aint a big deal to bats

Bats Physiology

• The High level of nitrogenous wastes in blood
• Turn water with diet Lean structure of the body to stay the same in structure

Hibernation

• Lots of nitrogenous wastes due to a heavy diet that is made of proteins.
• When processing kidneys will will work in conservation mode Lots of water in the body.VERY concentrated urine, it consist from - Few carbohydrates and fats
• Lean of the body structure Ozempic bats, therefore that consist from 3 traits
• Bats cannot tollerate below 68 at very low temps

Migration

• Eye of bats lack cones so they depend on the rods and is the vision is as is the same as normal eye but just the difference that can only see Black/ white
• Bat is the only in the mammal zone

Echolocation

• Is Not Unique to Bats such Dolphins
• The Sense is based off call that comes back as an eho which depends on the Loudness, and different oreintation

1793

• Spallanzani Discovered echolocation
• Binds bats Poked eyes,
  • Used wax to hear
• In 1930's Donald Griffen figured out echolocation

Echolocation traits

• Bats can prevent by growing 3 traits
  • Freqeuncy of a bat ranges 10-200 hz
• Can come down to 20hz Bats are whispering so for that to hear the call that create the sound that creates the same intensity

Bats inner ear

• • Bat Listen for where insects fly they speed it up or drop it

The inner ear of the bat

• Bats Can make a call that cannot be process quickly
  • Constant of calls bounce up
  • If high or Low they depend on the Frequency

Temperates

• Temperate are difficult to find in animal habitats so they may create new ones like hibernation

• Temperature obstacles ranges from is 60celcius to -60

• They can Survive from (32F to 106F)

• Is very important in known is that the bodies are warm

• Bats go hibernating in Summer

Mammal that hibranate

Rodents, bats, monotremes, hedgehogs, and marsupials are homeothermic