A list of definitions and concepts for a first Comparative Anatomy test.
What is comparative vertebrate anatomy?
The study of the functional morphology of the vertebrates
Compares body form & functionof various strucutres
Compares the similarities & differences in morphology among organism
Interprets similarities & differences in form within the contexts of ancestry, function, & evolution
What is the adaption paradigm?
An organism adapt to its environment with limitations from its ancestors.
Changes in gene frequency of a population through time
Change in the character states of organisms through time
Requires genetic variability - difference in the ability to survive and reproduce being linked to differences in heritable genetic variation
Differential reproduction & survival of organisms with certain character states or genotypes.
It is NOT survival of the fittest as the term "fittest" is typically thought of.
How does natural selection occur?
More offspring are produced than can survive each generation.
Population size exceeds the environment's carrying capacity
A critcial resource becomes limiting.
Additive genetic variation in competitive ability exists
Best competitors survive & reproduce
Results in an increase in the frequency of the traits that increased fitness in the next question
If the frequency of a given chracter state changes: It's natural selection in the current generation and evolution in the next generation.
What is adaptation?
Adaptation is a process of population becoming adjusted to a particular environment over many generations.
An adaptive trait is a structure, a physiological mechanism, behavior that increases the probability that an organism will survive to reproduce.
What are the kinds/types of selection?
Natural selection - Differential survival of certain genotypes or phenotypes
Artificial selection - Differential breeding of organisms with certain desirable traits by humans
Sexual selection - Differential mating success
What are the forms of selection?
Directional selection - Selects for an extreme phenotype at one end of the distribution; Mean, Median, & Mode all change; Standard deviation may increase, decrease, or remain the same.
Stabilizing selection - Tends to eliminate individuals at each end of the distribution; Mean, Median & Mode are stationary; Standard deviation decreases
Disruptive selection - Eliminates individuals with the mean character state, and selects for the two extreme forms; Mean may remain the same; Bimodal; Standard deviation increases; Gives rise to speciation
What is the evidence for evolution?
What is a species?
A group of interbreeding or potentially interbreeding organisms that are reproductively isolated from other similar organisms
What is allopatric speciation?
Generating new species in different geographic locations
Barriers arise that separate gene pools
No gene flow between gene pools
Differential selection, genetic dirft, & mutation within the different populations
Two populations come in secondary contact
What is parapatric speciation?
When organisms of the same species are not separated by a physical barrier, but sexual selection basically causes speciation.
What is some characteristics of the phylum Chordata?
Dorsal tubular nerve cord
Pharyngeal gill slits
Ventral Heart or Aorta
Tend to have some degree of cephalization & a post-anal tail
What are some characteristics of the superclass Agnatha?
Have a head with a brain & paired light sensitive organs "eyes"
Large persistent notochord
Two semicircular canals in each ear
Soft skin no scales
Two chambered heart (1 atrium, 1 ventricle)
What are some characteristics of the class Myxini, or the hagfishes?
200 slime glands - slime is used for protection; slime absorbs water and covers the gills of predators
Large tentacles around terminal nasal opening and mouth
No larval stage
5-15 of pouched gills
Poorly-developed cartilaginous skeleton
Multiple contractile vessels
Live in soft mud bottoms 25-600 m in depth, found up to 1000 m
Burrow in the mud
Live in cold water
Eat a variety of foods
Lay 20-30 yolky eggs
Size is 20-70 mm
Six genera & over 60 species
What are some characteristics of the class Cephalaspidomorhl or lamprey?
5 genera & 41 species
Ventral mouth with horny teeth
Poorly developed cartilaginous skeleton but has well developed skull and branchial region
Vertebrae lack centra but have rudimentary neural arches
Dorsal and caudal fins are present by not pectoral and pelvic fins
Lack a lateral septum so the are no epaxial or hypaxial muscles
Gills open into a respiratory tube that ends at the 7th arch
May be more closely related to bony fish than hagfish or sharks
Long larval stage, 5 years
Filter feed as larvae
Two feeding types as adult - parasitic and nonparasitic