vertebrate evolution where did we really come from? miss augulewicz
TRANSCRIPT
Vertebrate EvolutionWhere did we really come from?
Miss Augulewicz
Vertebrate Innovations Vertebral Column
Series of separate bones firmly joined as a backbone that defines the major body axis
Vertebrate Innovations Cranium
Supports and protects the sensory organs (eyes, ears, nose, mouth) and your brain
Step 1: Pre-vertebratesLancelet performed suspension feeding using
cilia and mucus
Mouth gets bigger Muscular pump forms that
can open and close Water & food are taken
in and pumped out
Reinforced by cartilage
Step 2: Agnathans-Jawless fish evolve
Feed using their muscular pharynx, not cilia and mucus
Lampreys, hagfish
Step 3: Gnathostomes- Jawed fish
The jaw evolves! Mouth opens, pressure
sucks large food in, jaw closes
No longer need pharyngeal slits to eat
Our ancestors were jawed fish: gnathostomes
Chondrichthyes (Sharks and stingrays) evolved in one direction they had bone then lost it
and are mostly cartilage
Osteichthyes (bony fish) evolved in another direction Kept the bone Ancestors to all present
day bony fish & vertebrates= SUCCESSFUL!
Half a billion years summed up in a few minutes…
http://www.youtube.com/watch?v=kgZRZmEc9j4
Your Inner FishSO….Looking back MUCH further than the chimpanzees, humans haves some other pretty old and interesting ancestors....
FISH!
How did we get on land?Meet the lungfish
LungfishLived in shallow fresh water that would
sometimes dry upBreathe using primitive lungs if no waterBreathe using gills if in water
Eventually fish evolved to come out of water…..
How did we learn this?
We look at the fossil record.
Tiktaalik
Tiktaalik lost some fish characteristics and gained lungs, arms & legs, primitive ears
Finding tiktaalik!http://www.youtube.com/watch?v=yvDQCa7rleI
What evolved next?
So they made it to land...but they aren’t fish anymore, what are they??
AmphibiansEvolution of lungs from the gut
Strengthening of limbs
Need to stay near water to lay eggs
Reptiles Can reproduce on land by
laying eggs
Get stronger limbs, use muscle and less energy to move
A new egg! Amniotic egg
Doesn’t need to be laid in water
Our ancestors can move to dry land!
From 2 different groups of reptiles we got....
Birds!
Mammals!
First mammals..Evolved from a reptile-mammal ancestor group called Therapsids.
Sort of look like rodents! Or weird dogs!
Oligokyphus
Inostrancevia
Mammalian characteristics Mammary glands: To
feed milk to our young
Fur or hair
Endothermic: maintains temperature from metabolic heat
There are three types of mammals based on their mode of reproduction
Monotremes lay eggs.
Marsupials have young that develop in the uterus for a short term. At birth, marsupial young crawl through mother's fur and into a pouch on the female's body to feed on mother's milk.
Placental mammals like humans develop through advanced stages in the uterus and receive maternal nutrients across the placenta.
Life of Mammalshttp://www.youtube.com/watch?v=2lCKc8tURtc&
list=PLD941E65FBD70DB46
Birds (Aves)Birds came from the dinosaurs!
This fossil, Archaeopteryx was once a dino with feathers!!
I can’t really talk too much about birds because they are my favorite and it would become a bird class.
Remember all the came before us!