Week 1 Objectives Flashcards
What are the 3 subphylum of the phylum Chordata?
1) Cephalochordata
2) Urochordata
3) Vertebrata
What are the major classes of subphylum Vertebrata?
1) Pisces
2) Tetrapods
Major characteristics of Pisces (one of the major classes of subphylum Vertebrata)
All fish extinct and alive
Characteristics of Amphibia (a class of tetrapods)
Amphibians and modern frogs, toads, salamanders, and caecilians
Characteristics of Reptilia (a class of tetrapods)
Reptiles
Characteristics of Aves (a class of tetrapods)
All birds -> This class is characterized by its feathers
Characteristics of Mammalia ( a class of tetrapods)
All mammals _> classified by hair and mammary glands
Characteristics of phylum Chordata that may be shared with members of the invertebrate phyla
Cephalization Complete digestive tract Bilateral symmetry Metamerism Triple lastly Eucoelomate body cavity Closed circulatory system Deuterostomy
Chordate membership requirements:
Dorsal hollow nerve chord
Pharyngeal “gill” slits, arches, and pouches
A notochord
Post anal tail (optional)
Major characteristics of vertebrates
Head
Trunk
Tail
Appendages
Characteristics of Cephalochordata ( a subphylum of phylum Chordata)
Notochord from tip of tail to tip of head
Ex. Amphioxus
Characteristics of Urochordata ( a subphylum of phylum Chordata)
Notochord only in tail
Ex. Sea squirts
Characteristics of Vertebrata ( a subphylum of phyum Chordata)
Notochord goes to the middle of the head
Contains vertebral column
Axes and panes used to subdivide the body of an organism displaying bilateral symmetry:
1) Cranal/Caudal
2) Dorsal/Ventral
3) Left/Right
3 types of planes:
1) Sagittal plane
2) Frontal (coronal) plane
3) Transverse (cross-sectional) plane
What is a frontal (coronal) plane?
Cranial/caudal & left/right
What is a transverse (cross-sectional) plane?
Dorsal/ventral & left/right
5 types of body movements:
1) Flexion
2) Extension
3) Abduction
4) Adduction
5) Rotation
Explain Flexion:
Takes place in a Sagittal plane around left/right axis
Brings 2 parts closer together
Explain Extension:
Sagittal plane around a left/right axis
Results in a straightening of a bent part
Explain Abduction:
Frontal plane around a Sagittal axis
Movement away from midline
Explain Adduction:
Frontal plane around a Sagittal axis
Movement toward a midline
Explain Rotation:
Movement of body part around its long axis (cranial/caudal) in a transverse plane
Characteristics of Acoelomates:
Lack a body cavity separating the somatic tube from the visceral tube
Doesn’t have true body cavity
3 types of organisms that can be recognized based on type of coelom or lack of coelom
1) Acoelomates
2) Pseudocoelomates
3) Eucoelomates
Characteristics of Pseudocoelomates:
Possess a cavity but is only partly derived from embryonic mesoderm
Have body cavity but not completely derived from embryonic mesoderm which is required to be a true coelom ate
Characteristics of Eucoelomates
Include most animals, including chordates
They possess a body cavity that is completely lend with derivatives of mesoderm
The only ones that have a true coelom
What is a mesentery?
Transition points where the visceral and parietal peritoneum join to form double layers
What are the linings associated with the splanchnic tube called?
Splanchnic or visceral peritoneum, visceral pleural, or viscera pericardium
What are the linings associated with the somatic tube called?
Somatic or parietal peritoneum, parietal pleural, or parietal pericardium
Characteristics of the somatic tube:
Outer tube interacts with external environment and consists of skin and skeletal musculature
Allows organism to detect changes in its external environment and to respond to those changes
Characteristics of the splanchnic tube:
Inner tube involved in metabolic functions
Includes gut tube and its derivatives such as the liver and pancreas
Responsible for nutrients brought into its lumen (cavity) from external sources and making the energy and building blocks (AA’s, fatty acids, monosaccharides, etc) derived from these nutrients available for anabolic and catabolic metabolism
How many pairs of appendages do all modern vertebrates have?
2
Define pectoral appendages
Appendages toward cranial end of body
Define pelvic appendages:
Appendages closer to the caudal end of the body
Define mesoderm:
1 of 3 embryonic germ layers
Gives rise to skeletal framework
Who has an internal mesoderm skeleton?
Only vertebrates… This is what makes them unique from invertebrates. Invertebrates only contain an external skeleton (exoskeleton)
Define myomeres:
Segmentally arranged blocks of skeletal muscle
In mammals, what partitions off pleural cavities from other cavities?
A muscular diaphragm
What separates the pericardial cavity from the pleuroperitoneal cavities in fish, amphibians, and some reptiles?
Fibrous transverse septum
What separates the pericardial cavity from the pleuroperitoneal cavities in some reptiles and birds?
A tendinous oblique septum
Collectively, mesodermal linings of cavities are known as what?
Serous membranes
Define dorsal mesentery:
Suspends gut tube from dorsal roof of coelom
Define ventral mesentery:
Connects gut tube to ventral floor of coelom
Defense Metamerism:
Refers to segmentation
Describes subdivision of body into repeating anatomical units on either side of the midline extending from cranial to caudal end
Define Tripoblasty:
Embryonic term referring to origin of the body plan from 3 embryonic germ layers (ectoderm, endoderm, mesoderm)
Name the 3 embryonic germ layers
1) Ectoderm
2) Endoderm
3) Mesoderm
Define the germ layer: ectoderm
The outermost layer, gets rose to outer layer of integumentary and nervous systems
Define the embryonic germ layer: endoderm
Innermost layer, gives rise to gut tube and derivatives
Define the embryonic germ layer: mesoderm
Middle Ayer, givers rise to connective tissues, cartilage, bone, muscle and other related structures and tissues
Define Deuterostomy
Not unique to chordates
Origin of oral opening in relation to anal opening during embryonic development
In deuterostomes, the original embryonic opening (the blastopore) becomes the anus, and the mouth develops as a secondary opening
Define Cephalication:
Not unique to chordates
Development of definite head characterized by an accumulation of sense organs
Define ontogeny
Embryonic development of an organism as well as any developmental changes that occur after birth or hatching
Define Teleology:
Idea that characteristics develop bc they are needed
Ex. Birds needed to fly so they developed wings
Define Baer’s Law
Features that develop earliest in ontogeny are oldest phylogenetically
Features that develop later in ontogeny are more recent in phylogenic development
Features common to all members of a major taxonomic group develop earlier in ontogeny than do subdivisions of the group
Define organic evolution (a component of the synthetic theory of evolution)
Based on fossil records, organisms today aren’t the same as those from the past and vice versa
Define genetic diversity (a component of the synthetic theory of evolution)
All members of a population exhibit genetic variation (except identical twins)
What are sources of variability for genetic diversity?
Sexual reproduction (independent assortment and crossing over), recombination (fertilization), mutation
What are the components of the theory of natural selection (a component of the synthetic theory of evolution)
Genetic variability exists in sexually reproducing populations
Some members of a population are more fit for the environments than others -> these individuals have a better chance of survival and having fertile offspring (survival of the fittest) -> These genotype so will become more frequent in the population over many years
If the environment stays the same, the population achieves genetic equilibrium and evolution slows down or stops
Who published the theory of natural selection?
Charles Darwin and Alfred Wallace
Who is the author of acquired characteristics?
Jean Baptistery Lamarck
What are the components of acquired characteristics?
An organism may develop an atomic changes in response to specific pressures it encounters at any point during its life
These acquired characteristics may be passed on to offspring
Define Analogy
Similarity in function in structures in 2 or more species
Neither the anatomy nor the embryo logical development is similar
Ex. Wing of bird and wing of insect
Define analogous
Structures similar in function but different in anatomical structure
Not derived from common ancestors
Define Homology
Structural similarity uniquely evolved due to inheritance from a common ancestor or developed from a common embryonic
Function doesn’t have to be similar
Define Homologous
Structures found in different organisms that are similar anatomically and in embryo development and may or may not be similar n function
Derived from common ancestor
Major differences between analogy and Homology
Analogy is not derived from common ancestor and Homology is
Analogy requires similarity in function and Homology does not
Homology requires similar structures and analogy does not
Define Homoplasy
Structural similarity between different organisms not due to inheritance from common ancestor
Define Parallelism
Independent development of similar characteristics in lineages that inherit from a common ancestor a potential for the trait but don’t directly inherit them
Ex. Gerbil-rat and kangaroo come from common ancestor -> both jump and have bushy tail for balance
Define Convergence
Independent development of similar characteristics n 2 or more lineages even though they don’t receive from the adaptations from a common ancestor
Ex. Dolphin and shark -> environment causes similarity
Define Paedomorphosis
Larval form does not metamorphose, larval form becomes the adult form and develops gonads and sexually mature
Ex. Amphioxus
Define Neoteny
A type of Paedomorphosis adult form retains 1 or more larval characteristic
Ex. External gills in salamanders
Explain how Paedomorphosis might be used to explain origin of vertebrates
Larval tunicate forms gave rise to cephalochordates and vertebrates (example of paedogenesis)
What geological period did vertebrates first appear?
Cambrian
What axis make up the sagittal plane?
The cranial/caudal & anterior/posterior
How does a pseudocoelomate differ from a eucoelomate?
Both posses body cavity but pseudocoelomates is only partly derived from embryonic mesoderm
What is a coelom?
Space separating somatic tube from splanchnic tube, lined by mesodermal derivatives associated with the 2 tubes
What is hypoxia like musculature?
Layers of skeletal muscle that form walls of body cavity as well as fish fins & tetrapod limbs
Vertebrate coeloms are divided into 2 subdivisions & mammals are divided into 3, what are these called?
Vertebrates: pericardial, pleuroperitoneal
Mammals: pericardial, pleura, peritoneal
What are the 3 main components of the synthetic theory of evolution?
- Organic evolution (organisms living today are not the same that lived in the past & vice versa)
- Genetic diversity (all members of a population demonstrate genetic variation)
- theory of natural selection (co-developed by Darwin & Wallace)
Which theory, authored by Lamarck, states that during its lifetime, an organism may develop anatomical changes in response to pressures it encounters & these traits may be passed to offspring?
Theory of acquired characteristics
Common ancestor of echinoderm and chordates were probably…
Sessile or semisessile Deuterostomous Coelomate Bilaterally symmetric Ciliated larval form Lophophorate
What are the major anatomical characteristics of amphioxus?
Lacks cartilage and bone, has myomeres used for movements, cranial end consists of conspicuous tubular pharynx w/ pharyngeal slits on both sides. Mouth opens isn’t pharynx & has an endostyle on floor of pharynx that secretes mucous which covers the inside of gill slits and traps food particles to bring to intestine.
Define a Clade:
Monophyletic group made up of an ancestor and all of its descendants
Define a paraphyletic group
Includes a common ancestor and some but not all of its descendents
Define a polyphyletic group
Includes descendants but not the common ancestor
Define synapomorphies
Derived characters that are shared by several lineages
Define a cladogram
A diagram that shows a sequential hypothetical evolutionary branching pattern of a group of Clare’s
Define apomorphy
Derived character (a derived character is different from the ancestral condition)
List major characteristics of urochordates and compare the adult and larval forms.
(I.e. Tunicates/sea squirt)
- Adults- sessile bag of fluid, lack notochord and dorsal hollow nerve cord, but have well developed pharynx with gill slits. Has 2 short hoses (siphons).
- Larva-have all 3 chordate characteristics
List the 5 classes of fish
- Agnatha
- Acanthodii
- Placodermi
- Chondrichthyes
- Osteichthyes
Give examples and characteristics of of the class Agnatha
- Lamprey & hagfish
- Lacks jaws and paired appendages
- Oldest known vertebrates
- All extinct
- Devonian period
- 10 pairs of cranial nerves (we have 12)
- Dermal armor (possibly used for protection and phosphate storage but we don’t know for sure)
Give examples and characteristics of of the class Acanthodii
- Climatius
- streamlines body, large scales, most are freshwater
Give examples and characteristics of of the class Placdermi
- Coccosteus
- Some are very large, they have a moveable head between head and trunk to be able to open mouth wider
Give examples and characteristics of of the class Chondrichthyes
- Sharks/rays
- Cartilaginous, lack ability to form bone, large eggs, paired double nostrils
Give examples and characteristics of of the class Osteichthyes
- Lungfish/sturgeon/common fish
- Can form bone
Compare the characteristics of the subclass ostracodermi with subclass cyclostomata
- Both lack jaws & paired appendages
- Ostracodermi have muscular pumping mechanisms, nasal openings and a pineal organ (photoreceptor) and dermal armor
- Cyclostomata has round mouth -> includes lamprey and hagfish
List 3 major developments that set gnathostomes apart from earlier fishes
- Development of jaws -> ingestion of food and presented of food allows for food storage
- paired appendages -> improved ability to pursue or escape
- buoyancy mechanisms (lungs/swimbladders) -> fish could control depth in water without having to swim continuously but sharks must swim to control depth and lack swim bladders!
List the major anatomical characteristic that distinguishes sarcopterygians from actinopterygians
-Fin anatomy: Sarcopterygians have lobe paired fins and Actinopterygians have ray fins
During which Paleozoic era did fishes appear?
Cambrian
Describe the significance of the major morhological development in the gnathostomes: development of jaws
can bite food into pieces, presence of stomach allows for food storage
List the 4 classes of tetrapods
- Amphibia
- reptilia
- Aves
- mammals
List an example and characteristics for Amphibians
- salamanders/frogs/toads
- have pedicellate teeth, cyclindrical vertebral centra, 2 auditory ossicles
List an example and characteristics for Reptilians
- Lizards/crocs/turtles/dinos
- classification depends on holes (fenestrae) & intervening bony arches on back sides of skulls: anapsids, synapsids, diapsids, euryapsid
List an example and characteristics for Aves
- common bird
- “feathered dinosaurs”
- replaced bony tail with feathers, have reduces digits without claws, lack teeth
List an example and characteristics for Mammals
- humans/dogs,kangaroos
- live birth, endothermy, hair/fur, mammary glands, 4 chambered hearts
What is the group of Devonian tetrapods presumed to have given rise to modern amphibians?
Temnospondyls
List the orders of moderns amphibians and their major characteristics
- caudates (urodeles): they have a tail
- anurans (frogs & toads): lack a tail
- apodans (caecilians): lack limbs
What are the 2 groups of anapsids? List the characteristics for the one that is considered the stem reptile for all other reptiles.
- Cotylosaurs: stem reptile-may have been several feet in length, had dermal armor, skulls laterally flattened, not skull openings behind orbits.
- Chelonia
What are the distinguishing features between the 2 groups of dinosaurs?
The pelvic girdle
- ornithischians: bird hipped
- saurischians: lizard hipped
What are the 3 sub groups of modern lepidosaurs & what is their skull type with regard to lateral, post orbital openings?
- sphenodon: true diapsid skull
- snakes- diapsid but lost both bars
- lizards- diapsid but lost lower bars
Why do dinosaurs form a paraphyletic group?
Because it includes the ancestor of birds and dinosaurs but doesn’t include the actual birds
List reptilian characteristics found in early birds such as Archaeopteryx
- bony tail
- separate fingers with claws
- teeth
What are some theories on the origin of flight in birds?
- as a means of thermal insulation
- insect-catching net
- allowed for better pursuit of prey or escape from predation
- may have allowed early archosaurs to roost in trees at night
What was the earliest group of synapsids?
Pelycosaurs
What are the characteristics shared by mammals & advanced therapsids?
- Secondary palate of premaxillary, maxillary, & palatine bones
- pterygoid bones fused to brain case
- enlarged dentary bone
- differentiation of teeth
- considerable regional differentiation of ribs and vertebrae
- jaw articulation pattern
- legs pulled in
- ilium extended forward
- elongated sacrum
- feet well developed
What some mammalian characteristics
- live birth
- endothermy
- respiratory diaphragm
- four chambered heart with completely divided ventricle
- neocortex
- double occipital condyle
- mandible consisting of a singe bone
- bony secondary palate
- loss of interclavicle (except in egg laying)
- hair/fur
- possess mammary glands
What are the 3 groups of modern mammals and what separates them?
- monotremes-egg laying
- marsupials- pouched mammals
- placentals- placental births
Identify the earliest group of mammals & describe their dentition
Morganucodonts- heterodont with triconodont molars
Birds are now thought to be most closely related to which of the following groups of reptiles? A) Pelycosaurs B) Pterosaurs C) Dinosaurs D) Cotylosaurs
C) Dinosaurs
Which component of the synthetic theory of evolution was proposed jointly by Darwin and Wallace? A) Organic evolution B) Genetic Diversity C)Paedogenesis D) Natural Selection
D) Natural Selection
Which of the following characteristics s unique to chordates? A) Coelom B) Triploblasty C) Deuterostomous D) Dorsal hollow nerve cord
D) Dorsal hollow nerve cord
All other animals are found in most other animals so they aren’t unique to chordates
The similar body shapes in the shark and the dolphin represent an evolutionary phenomenon referred to by which of the following terms? A) Parallelism B) Convergence C) Paedogenesis D) Neoteny
B) Convergence
The agnathans are the earliest known vertebrates. Which of the following would NOT be characteristic of agnathans?
A) Armor plates covering much of the body
B) Lack of jaws
C) Pineal opening
D) Paired fins
D) Paired fins
List the requirements for terrestrialism
- Dessication control
- Resistance to gravity
- Changes in organs for special senses
- Excretion of nitrogenous waste
- Changes in reproduction
Describe Dessication control (a requirement for terrestrialism):
- Amphibians are subject to Dessication when out of water for a long time and require aquatic environment for reproduction
- Amphibians depend on their skin for gas exchange so skin must be kept moist to allow diffusion of respiratory gasses and must be thin and well vascularized
- When deprived of water, the pituitary changes to secrete vasopressin affecting permeability of certain tissues and allows water that would otherwise be lost to enter tissue spaces and be retained
Explain resistance to gravity (a requirement for terrestrialism):
- Requires anatomical adaptations that resist the pull of gravity and provide the body with support
- These adaptations include more dorsal positioning of vertebral column, considerable development of the pectoral and pelvic girdles and limbs, attachment of pelvic girdle to vertebral column, reduction in axial musculature in favor of an increased mass and complexity of the limb musculature
- During evolution, vertebrae became interlocking bones and less flexible
List the organs that have been changed for special senses (a requirement of terrestrialism):
- Lateral line system
- Ear
- Eye
Describe the changes made to the lateral line system (part of a requirement for terrestrialism)
Well developed in most aquatic organisms and allows organisms to detect electromagnetic waves n the water and is used extensively to find pray (all organisms send out electromagnetic waves)
Describe the changes made to the ear (part of a requirement for terrestrialism):
The ear changed and became able to conduct sound waves in air rather than water
- Lagnea formed the cochlea
Describe the changes made to the eye (part of a requirement for terrestrialism):
Evolution of the cornea allowed for coarse adjustments, while the lens allowed for fine adjustment
Name the 3 classifications of eggs
- Microlecithal
- Mesolecithal
- Macrolecithal
List the 2 types of egg distribution:
- Isolecithal
- Telolecithal
Describe Microlecithal eggs:
Eggs containing a very small amount of yolk
Ex. Mammalian eggs (except egg-laying mammals)
Describe Mesolecithal eggs:
Contain a moderate amount of yolk
Ex. Amphibian eggs
Describe Macrolecithal eggs:
Contain a large amount of yolk
Ex. Bird and reptilian eggs
Describe Isolecithal eggs:
Small amount of yolk distributed evenly throughout
Only microlecithal eggs
Describe Telolecithal eggs:
Yolk is concentrated toward one pole of the egg
- The end of the egg with yolk concentration is the vegetal pole
- The opposite end of the egg with yolk free cytoplasm is the animal pole
- *Mesolecithal or Macrolecithal eggs
List the steps in development of a frog embryo from 1st cleavage through gastrulation:
1) 1st cleavage
2) 2nd cleavage
3) 3rd cleavage
4) Blastulation
5) Gastrulation
Describe the 1st cleavage in the development of a frog embryo:
- Begins in animal pole and sows in vegetal pole
- Mitotic activity not accompanied by growth
- Subsequent growth will result in formation of embryonic germ layers and beginning formation of specialized tissues and organs
- Produces 2 daughter cells (blastomeres)