Biology Exam #2
Card Set Information
Biology Exam #2
2014 2nd semester
Group of embryonic cells near the dorsal margins of the closing neural tube.
New adaptations are usually modifications of?
Pre-existing genes and structures
: Paired fins and jaws
Paired fins permits?
Increased accuracy in maneuverability
Hinged jaws permits?
Gripping and slicing of food items
Who were...Earliest Gnathostome Vertebrates?
Placoderm ancestor...given rise to?
Other gill slits were?
Modifications of skeletal rods supporting anterior gill slits
Modifications for respiratory
Age of fishes
Subphylum Urochordata are?
Subphylum Cephalochordata are?
Mother lays external fertilized eggs
Fertilized eggs develop internally-no food or nutriends given to child-just growing
"Live Birth"(no maternal support)
Maternal nutrition & live birth
3 "subclasses: of fish... What are they?
1. Subclass Actinopterygii
Members of this phylum exhibit secondary...derived radial symmetry?
Class Amphibia are (animals)?
Protostome with chitinous exoskeleton?
Class Amphibia are?
1st terrestrial vertebrates (tetrapods)
What's the only other successful animal colonizer of land?
What was selective pressure for the amphibians?
Climate cycles of the Devonian
Amphibians, adaptive radiation: Why?
Lack of competition
Carboniferous Period called?
"Age of the Amphibians"
Amphibians remain tied to water through?
Their physiology & meramorphosis
3 extant orders of Amphibia?
("tailed ones") salamanders
Mostly Northern Hemisphere
Largely temperate in distribution
("tail-less ones") frogs & toads
More specialized than urodelans
Many adaptations for survival
("legless ones") caecilians
Nearly blind, burrowers
Major Evolutionary Breakthrough?
Amniotic Egg Permits...
Full terrestrial existence
Shelled eggs and membranes permits...
Retention of water
Examples of amniotes
Closest living relative?
3 orders of Reptilia...
Order Squamata are...
Lizards and Snakes
Order Crocodilia are...
Crocodiles and Alligators
Order Chelonia (testudines) are...
Turtles and Tortoises
In what taxon did flight first evolve?
Modified scales (keratin) with multiple functions.
Flight permits exploitations (4)...
Was aerial reconnaissance
Access to nutritious food
During early Jurassic (~200 mya)
What extinction opened many niches for class Mammalia?
3 Major lineages of Mammalia that emerged during Mesozoic
Dorsal hollow nerve cord?
Developmental infolding of an ectodermal plate
Phylum Chordata is divided into 3 subphylas...
What are they?
1. Subphylum Urochordata
2. Subphylum Cephalochordata
3. Subphylum Vertebrata
Sister group to chordates?
Recent shared derived traits
Phyla Chordata have 4 synapomorphies... What are they?
2. Dorsal, hollow nerve cord
3. Pharyngeal slits
4. Muscular post-anal tail
Deuterostome embryonic cleavage difference
Radial and Indeterminate
Grow on top of each other
Can have identical twins
Protostome embryonic cleavage difference
Sprial and determinate
Deuterostome blastopore fate
anus develops from blastopore
Protostome blastopore fate
Mouth develops from blastopore
Eucoelom forms by outpocketing of the archenteron (enterocoelom)
Eucoelom forms by splitting of mesoderm (schizocoelom)
2 types of Eucoeloms
Eucoelomates divide into 2 clades based on..
Formation of eucoelom
Fate of blastopore
Type of cleavage
Body cavity is completely lined with mesoderm
Body cavity is
completely lined with mesoderm
2 types of coeloms
Characteristics of coeloms
Permits longer size
And greater complexity
Cushion suspended organs
Characteristics of animals that have
Dorsal, ventral, anterior, posterior
of sense organs,
Directional locomotion, avoidance, food-getting
Characteristics of animals that have
Meet environment from all sides
Sessile or planktonic
Of the remaining animal phyla...
Cnidarians show primitive radial symmetry
Other phyla are primitively bilaterally symmetrical
Phylum Porifera lack
An aggregation of similarly specialized cells united in performance of particular function.
4 branching points on Animalia
1. Parazoa/Eumetazoa Split
2. Radiata/Bilateria Split
3. Acoelomate/Coelomate Split
4. Protostome/Deuterostome Split
Ontogeny Recapitulates Phylogeny
Theory that stages in organism's embryonic development correspond to stages of its evolutionary history.
Produces testable hypothesis of genealogical relationships only from
recent shared derived characteristics
Employs all measurable similarities and differences in phenotypic characteristics without consideration of convergence
Names of 2 schools of Phylogeny
Category of classification
What is Phylogeny?
The evolutionary history of a species or group of species.
The study of the diversity of life (includes taxonomy & phylogeny)
What are Animals?
Multicellular, hererotrophic, eukaryotes with tissues that develop from embryonic layers
Lack cell walls
Structural proteins (e.g. collagen) hold bodies together
Unique→ nervous and muscle tissues
Most with sexual reproduction
Diploid stage usually dominant
Zygote undergoes cleavage→ Blastula→ gastrula embryonic germ layers
Only animals have HOX genes that regulate development of body form
What does HOX genes do?
Control the development of different parts
How is phylogeny determined?
By assigning a set of characteristics derived from multiple sources
Comparative molecular biology
Vertebrae phylogeny derived from...
Who is Ernst Haeckel?
He made the Biogenic Law
The animal kingdom is...
Other words, all animal phyla share common ancestor
There are over 30 animal phyla
Kingdom Animalia may evolved from...
A colonial flagellated protistan ancestor (choanoflagellate)
Endoderm forms during...
Gastrulation via inward growth