Exam One Flashcards
what is a clade?
- an evolutionary lineage
- a monophyletic group
In cladistics, groups are created based on…
derived characters
derived means
different from the ancestral condition
an apomorphy is a
derived trait
Clades are grouped on the basis of shared, derived characters, or
synapomorphies
Pleisiomorphies are…
ancestral characters – characters inherited unchanged from their ancestors
symplesiomorphies are…
shared, ancestral characters
pleisiomorphies and symplesiomorphies DONT show us…
degrees of relatedness
Crown vs Stem groups
- Stem lineages: are made up 100% of extinct species
- Crown lineages: there are still at least one species still alive
Sister taxon
the group that is most closely related but not in the group
more than half of vertebrates are..
fish!
phylogenetic trees show us…
evolutionary history
nodes represent…
hypothetical common ancestors
what is a taxon?
a group name only applied to monophyletic groups
Describe the relationship between systematics and taxonomy
A name is only applied to a monophyletic group and if it does not, then it is considered a bad name
On phylogenetic trees, time is…
relative, moving towards most recent events
fossils allow us to…
- Allows us to create more accurate phylogenies
- The field continues to advance
what are the mammalian synapomorphies?
- Produce milk with mammary glands
2. Real keratinized hair
synapomorphies
characteristics unique to a specific group
Apomorphy
different from the ancestral condition (derived traits!)
Synapomorphies need to be made to…
make trees more accurate
plesiomorphies
characteristics inherited unchanged from their ancestors
Why are plesiomorphies unhelpful for creating accurate trees?
Just because they are true for the group doesn’t mean it diserns them for others. For example, all mammals have four limbs but so do most vertebrates. As a result, it does not define mammals as a group
evolution does not have…
a goal
what is a morphology?
a character that can be measured
are most animals deuterostomes or protostomes?
protostomes
all metazoans are…
- Multicellular heterotrophs
- Motile (capable of movement) for at least some part of their life cycle
What was the cambian explosian and how did it happen?
the sudden diversifications of metazoans fueled by the predator and prey relationship
we are in phylum…
chordata
the sister taxa to phylum chordata is…
Ambulacraria
Phylum Chordata has three subphyla which are…
- Cephalochordata (lancelets)
- Urochordata (tunicates)
- Vertebrata
* * 1 and 2 are the “invertebrate chordates”
Phylum Chordata has three subphyla which are…
- Cephalochordata (lancelets)
- Urochordata (tunicates)
- Vertebrata
* * 1 and 2 are the “invertebrate chordates”
What are the characters of chordates?
- notochord
- dorsal hollow nerve chord
- segmented, muscular, postanal tail
- end-style
- larynx containing gill slits
What is the function of the notochord?
it provides structural support and something for muscles to contract against
what does the endostyle do?
secretes mucus secretion to assist with suspension feeding
our endostyle is
the thyroid
Why is the pharynx containing gill slits beneficial?
for suspension feeding!
why did gill slits not originally need to be used for breathing?
Because our ancestors were small and not very active, they could survive though surface area gas exchange through diffusion
what is diffusion?
Diffusion is an inactive process in which particles move from high concentrations to low
the opposite of extinct is…
extant
buccal cirri
generate mini current to pull water in, which passes over the pharynx for suspension feeding. Water comes out of atriopore and food waste comes out of anus
what do vertebrates display that non-vert chordates do not?
- Increased body size
- Increased activity
- Specialized organ systems
- Active use of gills for respiration
- Predaceous, made possible by vertebrate head
What is the relationship between bilateral symmetry and directionality?
We are able to move more calculated
what is development?
the process from zygote to adulthood/reproductive maturity
what is development?
the process from zygote to adulthood/reproductive maturity
When does the neural crest form?
as the neural tube develops
the neural crease in unique to…
vertebrates
What do migratory neural crest cells become?
they move to different parts of the body and become:
- some bones and muscles of anterior head
- almost all of the PNS
- adrenal glands
Basic vertebrate adult tissue types:
- Epithelial
- Connective
- Muscular
- Nervous
What allows me to hold a kidney (or any organ) without having a goop on the floor/why does it have a specific shape?
collagen: a protein that creates a matrix that holds cells in shape
what gives plants their shape?
structural polysaccharides
what gives animals with exoskeletons their shape?
the polysaccharide CHITIN
cartilage is formed by…
chondrocytes
chon-
cartilage
why is some cartilage hard?
it is mineralized
pros and cons of mineralized carbon vs. bone?
lighter and more flexible, but it is more prone to damage because it does not contain blood vessels
Why might a ray have mineralized cartilage towards the center but not on the outer pectoral fin?
Helps to resist exertive pressure of the muscles, which are located towards the center, and allows the organism to swim
Mineralized tissues, in vertebrates, are formed by
hydroxyapatite
in mineralized tissue, phosphate ions are important because…
they protect hydroxyapatite from dissolving due to lactic acid buildup
true bone is unique to…
vertebrates
bone is formed by…
osteocyte
bone replaces ________ during ____________.
bone replaces cartilage during development
bone is a matrix of ______ and ___________. Why is this beneficial?
bone is a matrix of collagen and hydroxyapatite .
Beneficial because:
1. The collagen allows for a little bit of bend but no break
2. The mineral (hydroxyapatite) allows it to take force
identical twins can have different bone mass based on lifestyle (gamer vs. lifter). this shows us that…
blood vessels also allow bones to acclimate to different stressors
two types of bone
- dermal
2. endochondral
two types of bone
- dermal
2. endochondral
where is the dermal bone formed?
in the skin
what type of bone was the first to evolve?
dermal bone
what does dermal bone become in our bodies?
our skull and our teeth
true teeth form over…
dermal bone
endochondral bone is formed in…
the cartilage
endochondrial bone is unique to…
bony fish and tetrapods
how is the endoskeleton formed?
osteocytes replace cartilage during development
where is the chondrocranium and what type of bone does it come from in vertebrates?
- surrounds the brain
- endochondral bone in higher vertebrates
what does the chondrocranium allow for?
structures to attach, such as extrinsic eye muscles
Interacts with splanchnocranium
what does the splanchnocranium form?
gill support
where does the dermatocranium form?
in the skin during development as outer cover
dermatocranium is made from…
dermal bone
what does the lateral line system do?
makes fish extremely sensitive to “water sound”
Chenosylia
Most similarly resembles our inner ear
How do schools of bait fish move in unison when a predator comes in?
lateral line system
can the lateral line system be felt from far distances?
yes
how is the Internal anatomy inside of ampullae different than lateral line system
Unlike the LLS the pores are concentrated at their snout, which allows them to located minute electrical fields that are close rather than movements that can be far distances away
how is the Internal anatomy inside of ampullae different than lateral line system
Unlike the LLS the pores are concentrated at their snout, which allows them to located minute electrical fields that are close rather than movements that can be far distances away
increased surface area allows for more _________. Why?
Directionality because there is more space between the lateral line system and ampullae
in the modern day, only __________ have paired fins
gnathostomes
paired fins allow for…
control of the body
ostracoderms are…
heavily armored
what is adaptive radiation?
an event of rapid diversification
what is a stem lineage?
a lineage in which every member is not extinct
fossils only form from…
minerals
the derived traits of ______ and ______ help sharks switch direction
short radials and small basals
distinctive characters of sharks
- cartilaginous skeleton
- jaw suspension
- high blood urea concentrations
why is the holistic jaw advantageous?
Allows sharks to have a subterminal mouth when advantageous. The snout makes sharks more dynamic (subterminal is advantageous) but when they want to eat they are able to make their mouth terminal when eating.
without their massive _______, nonbenthic rays/sharks would sink
livers
how do sharks change direction?
by tilting their pectoral fins
why are high blood urea concentrations important for sharks?
otherwise they would have to use active transport, which uses ATP
why are adaptions that conserve energy important in sharks?
- Food in the ocean is distributed PATCHILY
- They have to go long times without eating and need these adaptations to survive
how do most skates reproduce?
egg laying species
how do rays reproduce?
most give birth to live young
what is the sister taxon to Phylum Chordata?
Phylum Ambulacraria
what distinguishes a vertebrate?
Chordate with a cranium and a segmented axial skeleton or Associated embryonic
structures
The vertebrate head allowed organisms to
- participate in suction feeding
- larger brain (telencephalon)
- more complex sensory organs
The vertebrate head allowed organisms to
- participate in suction feeding
- larger brain (telencephalon)
- more complex sensory organs
What are the germ layers, from out to in?
- ectoderm
- endoderm
- mesoderm
- neural crest “germ layer”
what are the types of mineralized tissues?
- dentin
- enamel
- enameloid
- cementum
- mineralized cartilage
- bone
what were the three radiations of Elasmobranchii?
- Paleozoic
- Early Mesozoic
- Mid Mesozoic
distinctive characters of chondrichthyes
- cartilaginous skeleton
- skin
- lipid filled liver
- high blood urea
what is unique about the sharks cartilaginous skeleton?
- its an ancestral trait for most, but a derived trait in sharks
- Retain dentine, enameloid, and traces of bone in their teeth and placoid scales
- they retain mineralized (calcified) cartilage
what is unique about the sharks skin?
tough layer of collagen under skin that connects to the vertebral column via
collagen septa
perichondrial ossification
save
in non-benthic sharks and rays, what percent of their body mass is from the liver?
25-30%
a sharks liver is filled with…
low-density lipids and hydrocarbons
sharks livers make them…
naturally buoyant
which side of the sharks liver is bigger?
the right lobe
what is unique about sharks high blood urea concetration?
their high blood urea concentrations make them hyperosmolal to seawater, which eliminates the risk of cellular water loss due to osmosis and keeps them from spending as much energy osmoregulating.
General Characters of Modern Chondrichthyans
- vision
- chemoreception
- electroreception
- mechanoreception
describe the modern sharks vision.
their retinas are rod rich and they have tapetum lucidum, which allows them to see quite well in low light environments
modern sharks are able to respond to chemical concentration gradients as low as…
1 part per billion
the modern sharks have electroreception due to…
ampullae of lorenzini
what is the mechanism which modern sharks use for mechanoreception?
the lateral line system
lecithotrophy
the yolk supplies most nourishment
matrotrophy
the reproductive tract of female supplies nourishment
oviparity species…
all utilize lecithotrophy
vivparity species…
range from lecithotrophic to matrotrophic species
sarcopterygiians have scales that are coated by ______, derived from _______.
cosmine derived from dentine
actinopterygiians have scales coated by ________, derived from __________
ganoine derived from enamel
what are the types of mineralized tissues?
- dentin
- enamel
- enameloid
- cementum
- mineralized cartilage
- bone
in primative vertebrates, dermal bone formed…
dermal armor
the notochord is accompanied or replaced by…
vertabrae
what are the basic vertebrate structures?
- bone
- cranial skeleton
- axial skeleton
- vertebrae
- axial muscles
axial muscles are comprised of…
myomeres
what are myomeres?
overlapping sequential muscle segments
