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Modern Theory of Evolution
Change in genetic composition (gene pool) of populations over time (generations)
List Darwin’s Postulates of Evolution
1. Individuals vary within a population
2. Some variation can be passed from parents to offspring
3. In every generation, more offspring are produced than will ultimately survive to reproduce
4. Survival is not random, and those offspring that survive to reproduce are those with favorable variation
Systematics
The study of the diversity of organisms andtheir evolutionary relationships
Phylogenetics
the science of reconstructing evolutionary relationships
Taxonomy
the science of biological nomenclature and classification
Node
A split within a lineage resulting in separate diverging lineages
Root
Common ancestor of all organisms within a phylogenetic tree
characters
the traits which can be compared
character states
the various conditions of a character
Homoplasy (Homoplastic Characters)
Similarity of structures in function or external appearance but not in essential structure or origin
- characteristics that are overtly similar but which are not evolutionarily the same
- were not present in the most recent common ancestor
- are generally the result of adaptation to similar environments and indicative of convergent evolution
Describe a monophyletic group
Includes a most recent common ancestor plus all of its descendants. Also referred to as a clade - a natural group
Describe a paraphyletic group
includes a most recent common ancestor plus only some of its descendants. Also referred to as a grade - not a natural group
Synapomorphies
Define monophyletic groups and are the most important character in a cladistic analysis, which allows us to identify sister group relationships
How old is earth?
4.5 BYO
How old is life on earth?
3.9 BYO
Animals originate when (approximately)?
565 MYA
Name the three germ layers that characterize Bilateria
Ectoderm (outer layer - integument)
Endoderm (inner layer - lining gut)
Mesoderm (middle layer - forming muscle layers and numerous organs)
Into what two categories are bilateria divided into?
Bilaterally symmetrical animals are divided into two major groups based on the presence of a coelom
Schizocoelous
Characteristic of protostome animals (Protostomata)
- Blastopore forms mouth
- Anus forms from opening that develops
later
Enterocoelous
Characteristic of deuterostome animals (Deuterostomata)
- Blastopore forms anus
- Mouth forms from opening that develops later
Deuterostomes
Phylum Xenoturbellida
Ambulocraria
-Phylum Echinodermata
-Phylum Hemichordata
Phylum Chordata
-Subphylum Cephalochordata
-Subphylum Urochordata
-Subphylum Vertebrata
The five chordate characters that must be present at some stage during development.
1. Notochord
2. Dorsal Hollow Nerve Chord
3. Pharyngeal Slits/Pouches
4. Postanal Tail
5. Endostyle
Paedomorphosis
Neoteny - the retention of larval
characteristics in an adult form
Progenesis - attainment of sexual
maturity in a larval form
What is the scientific name of the Dogfish? (the fish disected in lab)
Squalus acanthias
What group does Squalus acanthias belong to?
Chondrichthyes
What are the little pores that can be found on dogfish? They will exude a “jelly” substance when squeezed.
Ampullae of Lorenzini
How might one tell the difference between adductor and abductor muscles?
Adductors add to the center line of the body while abductors abstract (subtract) from the center line
What are the names of the earliest known vertebrates found in China
Haikouella and Haikouichthys
What group are lampreys in?
Petromyzontiformes
Cenzoic era is commonly reffered to as the “Age of ________”
Mammals
The Devonian period is commonly referred to as the “Age of _________”
Fishes
What kind of group are Lizards? Monophyletic, paraphyletic, or polyphyletic?
Paraphyletic
What kind of group are snakes? Monophyletic, paraphyletic, or polyphyletic?
Monophyletic
The Jurassic and Cretaceous periods are known as what?
“Age of Dinosaurs”
What does Dinosaur mean?
Terrible Lizard
What three groups are in Dinosauria
Ornithischia, Saurischia, Aves
What is the difference between Ornithischia and Saurischia?
Ornithiscia are Bird hipped, pubis is parrel to the ischium; Saurishcia are lizard hipped, the pubis is perpendicular to the ischium
Which of the following is not considered to belong to the group “Rhipidistia”:
Eustenopteron
Panderichthyes
Acanthostega
Tiktaalik
Acanthostega
Tetrapoda are characterized by…
Muscular limbs with digits
the term “ammocete” refers to the larval stage of which group?
Petromyzontiformes
What are the modified sweat glands? And their function?
Ceruminous glands—lining of the external ear canal; secrete cerumen (earwax)
Mammary glands – secrete milk to feed the young
What are the four chromatapores?
Melanophores, Xanthophores, Erythrophores, Iridiophores
Melanophores purpose
brown and black pigment, Provide protection from UV radiation, Found in most vertebrates
Xanthophores color
Yellow pigment
Erythrophores color
Orange/Red pigment
Iridiophores
Possess guanine crystals, Iridescent colors through light scattering, Provides Blue/Green Coloration
Which germ layer is the epidermis derived from?
Ectoderm
Which germ layer is the dermis derived from?
Mesoderm
What are the major stages of embryological
development?
1. Zygote
2. Morula
3. Blastula
4. Gastrula
5. Neurula
Provide 2 synapomorphies of Osteichthyes.
Bony skeleton
Lungs or swim bladder (gas filled bladder)
What is the plesiomorphic condition of the
integument in vertebrates
a layered structure with scales or dermal armor.
What are the 3 subphyla of chordates and what is
our current understanding of their evolutionary
relationships.
the three subphyla are Cephalochordata, Urochordata, and Vertebrata, which exhibit a hierarchical evolutionary relationship, suggesting that vertebrates evolved from a common ancestor shared with the other subphyla.
Von Baer’s law
A general principle of embryology stating that the development of a species proceeds from more general to more specific forms, indicating that early embryos of different species exhibit similarities.
Biogenetic law
The principle that the development of an embryo follows the same progression as the evolutionary history of the species, often summarized by "ontogeny recapitulates phylogeny."
Provide two characters that Myxiniformes and
Petromyzontiformes share in common and one
difference between them.
Both Myxiniformes and Petromyzontiformes are jawless fish that possess a notochord and have a similar larval stage, but Myxiniformes are characterized by their lack of eyes and the presence of slime glands, whereas Petromyzontiformes have well-developed eyes.
What type of characters can inform us about
phylogenetic relationships.
Synapomorphies, or derived characteristics, can inform us about phylogenetic relationships by highlighting traits that are unique to specific lineages.
Provide the three
extraembryonic membranes found only in the eggs
of amniotes and their function.
The three extraembryonic membranes are the amnion (which protects the embryo), chorion (involved in gas exchange), and allantois (which stores waste products and aids in respiration).
What fossil group of fishes is the earliest group to
possess jaws? What are vertebrates which possess
jaws referred to as (e.g., classification)?
The earliest group of fishes that possessed jaws is the placoderms. Vertebrates with jaws are referred to as gnathostomes.