milk olli week 6 ho evolution of milkolli.illinois.edu › downloads › courses › 2019...
TRANSCRIPT
10/15/19
Week 6Oct. 14
All About Milk Walt Hurley
Why Milk ?
Evolution of Mammals, Lactation, Milk
I
What are the main components in milk?
• Water• Lactose• Fat (Lipid)• Proteins• Minerals• Vitamins• Others
Bioactive factors
10/15/19
Milk
Reproductive strategy
LactationWhy?
What are some of the differences?
Nature of parental (maternal) investment
Extent of offspring maturity when entering the world
Number of offspring per reproductive cycle, and per lifetime
Live birth vs hatchling
10/15/19
Earth formed4.5 billion
years ago
Life starts3.5 billion
years ago
Big Bang
Our story begins
13.77 billion years
400 million years ago Today
~400 million years
400 mya Today
365 mya
Eggs are still laid in water, fertilization still occurs in water, requires larval stage (think tadpole)
They crawled out of the water
Tetrapods started living part of their life on land
first forests; plants developed more advanced vascular systems and refined reproductive structures
360 mya - first seed-bearing plants
385-360 mya
10/15/19
400 mya
Assembly of supercontinent Pangea
175 mya – Pangea starts to break apart
Shift from large tracts of swampy wetlands to isolated rainforest tracts separated by
arid landscapes
335 mya
Today
Pangea
400 mya
312 mya Synapsids evolve; became dominant species 286-260 mya
Most likely had parchment-shelled eggs
Higher water loss from the egg
Living in drier environments
No fossil record of calcified egg shells, soft shells do not fossilize
Parchment shell can absorb water
Evolve behaviors that ensure eggs develop under moist conditions – to maintain fluid balance of the embryo
Dimetrodon, top-predator synapsid
Permian periodToday
Pangea
10/15/19
400 mya Today
Permian-Triassic extinction event
Loss of biosphere:96% of all marine species70% all terrestrial vertebrate species
57% of all biological families83% of all genera
Causes:3 phases of the extinction
Meteor impact eventsMassive volcanic eruptionsRelease of underwater methane
251 mya
Permian Triassic
Mass extinction
Pangea
400 mya
Moder
n birds e
volve
dDinosaurs evolved within a
single linage of archosaurs
Archaeopteryx
(ancestor of modern birds)
Dinosaur extinction
Permian Triassic
Dinosaurs and Birds
Permian-Triassic extinction event
243-233 mya150 mya ~ 6
0 mya
66 mya
Jurassic Cretaceous Paleogene Neogene
Triassic-Jurassic extinction event
Pangea
251 mya
Early Proto-Mammals
Flowering plants125 mya
10/15/19
From ~230 mya thru 66 myaClade: DinosauriaDominant terrestrial vertebrate after 201 mya
(Triassic-Jurassic extinction event)
Birds are modern feathered dinosaursBirds are the only dinosaur to survive past 66 mya
(Cretaceous-Paleogene extinction event)
Oh, yes we did!
400 mya Today
Permian-Triassic extinction event
Permian Triassic
275 mya Synapsids gave rise to the Therapsids in late Permian
Therapsids included the cynodonts (260 mya)
A cynodont (Oligokyphus)
Gave rise to the mammals in the late Triassic (225 mya)
251 mya
225 mya
Pangea
A therapsid (Instrancevia)
10/15/19
400 mya
C-P extinction
Permian Triassic
P-T extinction
Jurassic Cretaceous Paleogene Neogene
T-J extinction
Pangea
tetrapods
synapsids
therapsids
cynodonts
mammals
reptilesdinosaurs
birds
Didelphodon vorax
dinosaur-hunting (?) marsupial-ancestor
69-66 mya
Oligokyphus 231-113 mya
Massetognathus
235 mya
Kayentatherium201-175 mya
125 mya
(oldest record of a mammal with spines and hair that can be examined on the cellular level)
Spinolestes xenarthrosus
Early Mammals/Proto-Mammals
Morganucodonta
210-140 mya
Eozostrodon210-190 mya
The first true mammal?
400 mya
a
b
c
d
e
f
g
a b cd e f g
Pangea
Permian Triassic Jurassic Cretaceous Paleogene Neogene
10/15/19
Hard-shelled egg (chicken)
Parchment or soft-shelled eggs (reptiles)
What does a soft-shelled egg need that a hard-shelled egg does not need?
protection from:microbial action on the embryo
secretion of a water-based secreta from the mother
drying out, water loss
What do eggs need in order to hatch?
Incubation, warmth Mother (or other?) laying on the eggsnesting behavior
secretion of a water-based secreta from the mother that contains antimicrobial activity
Evolution of skin glands on the ventral surface of the animal
Exocrine glands that secreted a fluid loaded with antimicrobial activities
Components of the secretion of particular nutritional value to the young evolved later
10/15/19
What does this have to do with milk?
Early skin gland (proto-mammary gland) secretions:
Water-based
Rich in antimicrobials
lactoferrin lysozyme antibodies antimicrobial peptides others
Not rich in nutrients at least not initially
Rich in bioactivity
Evolution of Mammary GlandsMonotremes
Marsupials
Hair follicles and sebaceous glands are linked to development of the nipples; hair follicles penetrate the nipple epithelium, are then shed, leaving a duct (galactophore) that connects to the mammary gland to the surface of the nipple
No nipples; the mammary “patch” is comprised of the mammary glands associated with hair follicles and sebaceous glands
Placental mammals
Lost the direct association of hair follicles with the mammary gland Mammary glands are
associated with
10/15/19
Was everything new, or just repurposing existing genes and functionalities?
Prolactin Oxytocin
Lysozyme
a-Lactalbumin
ancestral gene
has wide range of functionsuterine contractions during parturition
milk ejection/letdown
the “love” hormone
a brain neurotransmitter
social bonding, trust, parental carereproductive functions
fluid balance, mineral balance
prolactin and growth hormone evolved from a common ancestral gene 345 mya
ancestral gene evolved 500+ mya
maternal/paternal behaviors in mammals
brooding behaviors in birds
antimicrobial
lactose synthesis
Modern Mammals
10/15/19
Mammals~5,400 species of mammals
We know things about the milk composition on <5%Classification
Kingdom
Phylum
Subphylum
Class
Animalia
Chordata
Vertebrata
Mammalia
Mammals What distinguishes mammals from reptiles and birds?
hair 3 ear bones
mammary glandshigher-order brain functions such as sensory perception, cognition, generation of motor commands, spatial reasoning and language
neocortex
10/15/19
1 ear bone
3 ear bones
Size range from: 1.5 inch
>100 feet
Craseonycteris thonglongyai
Bumblebee bat~5,400 species of mammals
Etruscan shrew
Suncus etruscus
Balaenoptera musculus
Blue whale
10/15/19
Today’s Mammals
Monotremes Marsupials
Placental Mammals
Evolved into Evolved into
Monotremes diverged before the divergence of marsupials and
eutherian (placental) mammals
Echidna may be derived from a platypus-like ancestor
Evolution of Mammals
10/15/19
Evolution of Mammals
Base
d on
Mor
phol
ogy
Base
d on
Gen
etic
Cha
ract
erist
ics
Monotremes
Egg laying mammals
Australia
New Guinea
Duckbilled platypus
Classification
Kingdom
Phylum
Subphylum
Class
Animalia
Chordata
Vertebrata
Mammalia
MonotremataOrder
Ornithorhynchus anatinus
Mammals
Genetic evidence indicates monotremes first evolved 180 – 210 mya
Oldest fossil is from only 120 mya
Platypus and echidna diverged between 19 and 48 mya
Male's spurs deliver a venom
10/15/19
Lays 1-2 eggs in a burrow
Hatch at 12 days
Hair at 7 weeks, eyes open at 9 weeks, suckled for 16 weeks
Duckbilled platypusOrnithorhynchus anatinus
The unusual appearance of this egg-laying, duck-billed, beaver-tailed, otter-footed mammal baffled European naturalists when they first encountered it, and the first scientists to examine a preserved platypus body (in 1799) judged it a fake, made of several animals sewn together. [Wikipedia]
10/15/19
4 species of Echidna(spiny anteater)
Family: Tachyglossidae
Australia
New Guinea
Genus: Tachyglossus
Tachyglossus aculeatus
Genus: Zaglossus
Zaglossus attenboroughiZaglossus bruijniiZaglossus bartoni
Monotremes
Egg laying mammals
Echidna Echidna
half-woman and half-snake,
lived alone in a cave
mother of many monsters of Greek mythology
perceived to have qualities of both mammals and reptiles
10/15/19
Spines and fur of an echidna
TachyglossusThe “Pouch”
Do not have a permanent pouch. Have contracting muscles in the abdomen, which forms a pouch-like
fold.
Both male and female echidnas can form a pouch.
10/15/19
††, the two tufts of hair in the lateral folds of the mammary pouch from which the secretion flows, b.m, Pouch; cl, cloaca; g.m, groups of mammary glands.
TachyglossusThe “Pouch”Lower surface of brooding female
dorsal view of the pouch and mammary glands
TachyglossusExposed mammary gland
After oxytocin injection
10/15/19
Tachyglossus
Newly hatchedMilk ejected onto the skin
Tachyglossus
Newly hatched
Puggles
Lays 1 egg
Lives in mother's pouch for 12 weeks
Hatches in 9 days
Female lays her egg by lying on her back, rolling it down her stomach and enveloping straight into her “pouch”.
10/15/19
Puggles
Tachyglossus
At 12 weeks eyes open, leaves the pouch for a nest burrow
Weaned at 20 weeks
Marsupials
Young born live, but very immatureAustraliaNew Guinea
kangarooswallabyskoalapossumswombatsTasmanian devilothers
Classification
Kingdom
Phylum
Subphylum
Class
Clade
Animalia
Chordata
Vertebrata
Mammalia
Theria
Metatheria
Subclass
Infraclass Marsupialia
South AmericaCentral AmericaNorth America
Nurse in a pouch
334 species:
Mammals
Macropus eugeniiTammar Wallaby
Adult
Marsupials have lactation lengths 5-10 times longer than placental mammals of comparable body weight
10/15/19
Tammar WallabyMammary gland
Note nipples
Tammar Wallaby
70 day old
150 day old
200 day old
Macropus eugenii
Begins to leave the pouch ~200 days
Detaches from the nipple at ~100-125 days, but remains in the pouch
Weaned at about 300-350 days
Newborn
Born at ~28 days
Climbs unaided into the mother’s pouch
Swallows a nipple
10/15/19
Wallaby
35 day old
Nipple suckled by 248 day old
60 day old
Nipple suckled by 260 day old
Nipple suckled by 210 day old Joey at time it first leaves the pouch
Wallaby Milk Composition
Days of Lactation
Perc
ent o
f Sol
ids
Birth Releases from nipple
First leaves the pouch Weaned
10/15/19
100 200 300 400
Age of Young (days)
20
40
60
80
100M
ilk In
take
(mL/
day)
Tammar Wallaby Milk Intake
Releases from nipple
First leaves the pouch
Weaned
MarsupialsVombatus ursinus tasmaniensis
Common Wambat
Tasmanian Devil
Sarcophilus harrisii
Virginia Opossum
Didelphis virginiana
Onychogalea fraenata
Bridled nail-tailed wallaby
Macropus rufus
Red Kangaroo
Common Bushtail Possum
Trichosurus vulpecula
10/15/19
Phascolarctos cinereus
Koala bear
Female koala carries her baby in her pouch for about six months.
Marsupials
Virginia Opossum
Didelphis virginiana
Teaspoon full of newborn opossums
Marsupials
10/15/19
15 day old opossums Marsupials
Placental mammals
Young born more matureEverywhere
Largest orders are:
Classification
Kingdom
Phylum
Subphylum
Class
Clade
Animalia
Chordata
Vertebrata
Mammalia
Theria
Eutheria
Subclass
Infraclass Placentalia
Able to nurse independent of the mother
~95% of all mammalian species
Rodentia (1,500 species)Chiroptera (bats; >1,300 species)Soricomorpha (moles, shrews, solenodons; ~350 species)
Mammals
10/15/19
Southern Short-Tailed Shrew
Blarina carolinensis
Etruscan Pygmy Shrew
Suncus etruscus
European Mole
Talpa europaea
Myodes glareolus
Bank vole
Soricomorpha
Hispaniolan solenodonCuban solenodon
Carnivorous
Nocturnal
Venomous
Dig in the dirt for insects worms, snails, small frogs and reptiles
Uses its teeth as a syringe to inject venom into its target
Venom is not lethal to humans, but wear gloves when you adopt one for a pet
Cuba
Haiti, Dominican Republic
Soricomorpha
10/15/19
Cloven-hoofed, ruminant mammals
Bovidae
bison
African buffalo
water buffalo
antelopes
wildebeest
impala
gazelles
sheep
goats
muskoxen
domestic cattle
Classification
Kingdom
Phylum
Subphylum
Class
Family
Genus
Species
Animalia
Chordata
Vertebrata
Mammalia
Artiodactyla
Bovidae
Bos
Bos taurus
Order
Subfamily Bovinae
Mammals
even-toed ungulates
large mammals with hoofs
Classification
Kingdom
Phylum
Subphylum
Class
Family
Genus
Species
Animalia
Chordata
Vertebrata
Mammalia
Artiodactyla
Bovidae
Bos
Bos taurus
Order
Subfamily Bovinae
10 genera of medium to large-sized ungulates
Bovinae
bison
African buffalo
water buffalo
4-horned antelope
spiral-horned antelope
yak
domestic cattle
Mammals
10/15/19
Subspecies of Bos taurus
Bos taurus supercutieous
Very prevalent in urban areasClassification
Kingdom
Phylum
Subphylum
Class
Family
Genus
Species
Animalia
Chordata
Vertebrata
Mammalia
Artiodactyla
Bovidae
Bos
Bos taurus
Order
Subfamily Bovinae
Mammals
Subspecies
Bos taurus primigeniusaurochs
extinct since 1627
Eurasian aurochs
Indian aurochs
North African aurochs
Classification
Kingdom
Phylum
Subphylum
Class
Family
Genus
Species
Animalia
Chordata
Vertebrata
Mammalia
Artiodactyla
Bovidae
Bos
Bos taurus
Order
Subfamily Bovinae
Mammals
plural: aurochsen
10/15/19
Subspecies
Bos taurus taurus Bos taurus indicus
Bos taurus primigenius
Taurine cattle
aurochs
European cattleIndicine cattleHumped cattle
extinct since 1627
Eurasian aurochs
Indian aurochs
North African aurochs
Classification
Kingdom
Phylum
Subphylum
Class
Family
Genus
Species
Animalia
Chordata
Vertebrata
Mammalia
Artiodactyla
Bovidae
Bos
Bos taurus
Order
Subfamily Bovinae
Mammals
plural: aurochsen
Cattle breeds
Over 1,000 breeds of cattleOver 340 breeds of dogs
Holstein
Angus
Hereford CharolaisGir or Gyr
Kankrej
10/15/19
Dual purpose
Triple purpose
Ayrshire
Guernsey
Jersey
Holstein-Friesian
Shorthorn
Brown Swiss
Thank you for your attention.Any questions?