Animal Physiology

1
Animal Physiology
2
By the end of this class you should understand

• The system and mechanics of determining how
  organisms are related
• How to arrange animals on a phylogenetic tree
• The purpose and importance of the major
  physiological systems of animals
• The physiological differences between different
  groups of animals
• Why we must pee in a cup to get a job

3
Kingdom Animalia

• The first animals (similar to modern sponges)
  evolved around 1 billion years ago
• Probably the first multicellular organisms
• Like all modern animals, they had to eat food to
  grow and had no cell wall
• Animal diversity was limited until the Cambrian
  Explosion

4
Why the Cambrian Explosion?

• The supercontinent Pannotia (before Pangaea)
  broke up, restricting gene flow and creating new
  environments
• Homeotic genes were now evolved that controlled
  body plan
• Oxygen content in the atmosphere and ocean may
  have been rising
• Animal cells all have mitochondria so this would
  have benefitted them

5
Cambrian Explosion
6
Morphology and Phylogeny

• Quick Question Who do you think is most closely
  related of these three organisms?
• Seagull
• Fruit Bat
• Common Rat
• Can you place them into this phylogenetic tree?

7
Possible Arrangements
8
Common Ancestry

• We know the rat and bat are more closely related
  because they are both part of class mammalia
• If you were paying attention yesterday
• What this means is that they had a common
  ancestor with characteristics that they both have
  that the other animals dont have
• These predictions can be made by looking at cell
  structures and embryos as well as bones

9
Prediction of Ancestry

• The common ancestor of all eukaryotes
• Had membrane-bound organelles like nuclei and
  mitochondria
• The common ancestor of all animals
• Was multicellular, ate food and had no cell wall
• The common ancestor of the bilateria group
• Had three layers of tissue as an embryo and had
  bilateral symmetry

10
What about Echinoderms?

• Its true that echinoderms are part of bilateria
  and yet they are radially symmetrical instead of
  bilaterally symmetrical
• The embryo of the echinoderm is bilaterally
  symmetrical and its opening becomes its anus
• Evidence suggests that embryo structure changes
  more slowly than symmetry, so it is more likely
  that echinoderms are closely related to chordates
  and lost their symmetry
• The chance that they are closely related to
  jellyfish but their embryos also develop like
  chordate embryos is considered very unlikely

11
Compare These Trees

• If this tree is correct, flying evolved twice,
  but having fur and making milk for babies evolved
  only once

• If this tree is correct, flying only evolved
  once, but having fur and making milk for babies
  evolved twice

12
Certainty

• Recall that in science nothing is every 100
  certain, all we have is evidence
• The theory of evolution matches all data, and the
  tree of life is the best possible fit for all the
  probabilities
• New fossils are still being discovered and they
  often rewrite the tree of life
• The missing link between humans and chimpanzees
  was sought for a long time

13
Circulation

• The most important system in animal homeostasis
  is the circulatory system
• Bring nutrients and oxygen to all cells
• Removes wastes from all cells
• Nutrients are put in by the digestive system
• Circulatory system must be cleaned by the
  excretory system (or renal system)

14
Circulation in Sponges

• The simplest circulatory system is in sponges
• Probably similar to the first circulatory system
  in our common ancestor
• Seawater is pumped through the body of the sponge
  by cells with flagella
• The cells of the sponge are filter feeders that
  grab food out of the seawater and eat it
  themselves
• Essentially a colony of animal cells cooperating

15
Circulation in Bilateria

• In the most basic marine animals, ocean water is
  used as the circulatory system to allow things to
  move to all cells
• This is inefficient, since ocean water doesnt
  carry as much oxygen
• In addition to being bilaterally symmetrical, all
  bilateria have circulatory organs that move a
  liquid through the body
• Can keep oxygen-transporting materials in this
  fluid
• Can keep this fluid clean and free of bacteria

16
Circulation in Mollusca

• Mollusks have a large diversity in their
  circulatory systems
• Gastropods (snails) and Bivalves (clams) have an
  open circulatory system
• A heart pumps fluid through their body but it is
  not contained in vessels and is called hemolymph
• Cephalopods have a closed circulatory system for
  more efficient delivery of nutrients
• Nutrients leave the blood when it goes through
  capillaries

17
Circulation in Arthropoda

• Arthropods all have an open circulatory system
• Their exoskeleton is made of chitin, which is a
  dense carbohydrate that makes their bodies
  impermeable to water
• Their organs are bathed in hemolymph which
  nourishes their cells
• Their circulation is poor since their heart is
  just stirring their fluids through their body

18
Circulation in Echinodermata

• Echinoderms are similar to early chordates but
  have developed radial symmetry
• Like sponges and unlike more advanced
  invertebrates, they use seawater as their
  circulatory system
• They use a water vascular system to nourish their
  body
• They also use the water vascular system to move
  by pumping water through tubes in their arms to
  make themselves move

19
Circulation in Fish

• Fish and other vertebrates all have a closed
  circulatory system
• Fish have a two-chambered heart which pumps blood
  over their gills and through their body in one
  big squeeze from the ventricle
• Advantage blood is always oxygenated when it
  enters the body
• Disadvantage blood flow through body is slower
  since it has already lost a lot of its pressure
  on the gills

20
Circulation in Amphibians and Reptiles

• Amphibians and most reptiles have a
  three-chambered heart
• Blood collects in two collecting chambers, one
  from the lungs or gills and the other from the
  body, then pumped by the well-muscled ventricle
  into tubes that lead back to both
• Advantage better circulation in body
• Disadvantage some blood is not oxygenated

21
Circulation in Birds and Mammals

• Crocodiles, birds and mammals have a
  four-chambered heart, which is the most advanced
  heart system for maximum efficiency
• Blood from the body is pumped to the lungs, blood
  from the lungs is pumped to the body
• Advantage best oxygen delivery and best
  circulation
• Disadvantage requires a higher metabolism

22
(No Transcript)
23
Excretory System Needs

• All organisms must remove waste chemicals in some
  way
• The 1 waste to remove is ammonia, which is
  produced when protein is metabolized to sugar or
  fat
• Marine organisms can simply secrete the ammonia
  into the water around them
• Land animals cannot do this because it wastes too
  much water

24
Behold the Kidney!

• The kidney is an organ that collects and stores
  wastes like ammonia (can be turned into urea to
  save water)
• Can usually also secrete water or salt to keep
  the salt/water balance in the blood safe
• Blood or hemolymph filtrate is called urine and
  is essentially all the wastes from blood
• Human kidneys are very effective since they must
  also balance water and salt levels

25
Advanced Excretory System

• The more an animal must go without water, the
  better its excretory system must be
• Human kidneys are very good but no match for
  desert animals!
• A better excretory system is also needed when an
  animal eats a lot of protein for energy
• This is part of why the Atkins diet can mess up
  your kidneys
• Cats often develop kidney problems as they age,
  since most other carnivores they are related to
  eat plants as well as meat

26
Why Pee In A Cup?

• When we take chemicals into our body that do not
  belong, they are broken down by the liver
• These drug by-products collect in the kidney and
  are removed by urination
• Drug tests are basically a test for these drug
  metabolites in the urine
• These tests can be fooled by drinking a crapload
  of vitamins and minerals, but that is super bad
  for your kidneys and theyll know you did that
  anyway

27
See you in lab!

• More plants in lab today!