Lecture 1-4 (Quiz 1) Flashcards
What is a taxon?
Any group of animals that is recognized in a classification
Define phenotype.
Physical characteristics
What does genotype refer to?
Genetic make up
What is phylogenetics?
The study of evolutionary history of life on Earth
What is the goal of phylogenetic trees?
To represent how we believe organisms evolved and are related to each other
What are cladograms?
Branching patterns that represent evolutionary relationships
What is the purpose of cladeograms?
To organize organisms according to their ancestors
Define homoplasies.
Superficially homologous traits independently acquired due to reasons other than common ancestry
What are homologies?
Structures derived from a recent common ancestor; inherited traits indicating relatedness
What are pleisiomorphic characteristics?
Characteristics that are present in the ancestor and still present; shared ancestral characteristics
Define synapomorphic characteristics.
Characteristics that are unique to the group of interest
What is Phenetics?
Numerical taxonomy that arranges organisms based on the highest number of similarities
Took off in the 1980s with the advent of computers but is considered outdated due to its limitations.
What is a downside of Phenetics?
Includes homoplasies, which can misrepresent true relationships
Homoplasies refer to traits that are similar due to convergent evolution rather than shared ancestry.
What is Cladistics?
A method of arranging organisms with an emphasis on genealogy to reduce the occurrence of homoplasies
Cladistics looks backward at the evolutionary history of organisms.
Provide an example of Cladistics.
Class Birds in Reptiles
What is Evolutionary Systematics?
The study of the diversity of organisms and the evolutionary processes that underlie it, focusing on more than genealogy
It prioritizes the extent of divergence among species.
Provide an example of Evolutionary Systematics.
Class Birds
What does Parsimony refer to in biological classification?
The simplest explanation or option
In taxonomy, parsimony seeks to reduce the number of evolutionary changes.
How many extant mammal species are currently recognized?
6,640 extant mammals
What is the only fixed unit in classification systems?
Species
Everything above species is subject to rejection or modification.
True or False: In classification systems, everything above species is fixed.
False
What is the Naming system?
Bionomial nomenclature system
Who developed the bionomial nomenclature system and in what year?
Linnaeus in 1758
What are the three parts of the bionomial nomenclature?
Genus, specific epithet, and authority
What does ‘authority’ refer to in the context of bionomial nomenclature?
The person that described the species
Provide an example of bionomial nomenclature.
Homo sapiens Linnaeus 1758
What does the notation ‘Homo sapiens (Linnaeus 1758)’ imply?
Linnaeus originally described the species but the name may have been changed by someone else
Why is Latin used for scientific names?
Because it is a universal and dead language
What is the ICZN?
International Commission on Zoological Nomenclature
What is the purpose of the ICZN?
To create, provide, and regulate rules on naming
What are the rules for naming under the ICZN?
- It must be Latinized
- Description
- Type - example holotype
4.Geographic Range - Differential Diagnosis
- Measurements
- Remarks section
- List of specimens examined
- Distinguishing characteristics
- Not anonymous
- It can’t be a synonym or a homonym
What is a holotype?
A single specimen, designated by the author, upon which a description of a new species is based.
What are syntypes?
A series of specimens, designated by the author, upon which a description of a new species is based. (=COTYPES)
What is a neotype?
A substitute ‘type’ specimen designated by the original author or someone else if the original holotype or syntypes are lost or destroyed.
What is a lectotype?
A single specimen, picked from the original series of syntypes by the author or someone else, and used as the representative ‘type’ specimen.
What are paratypes?
The additional specimens collected at the ‘type’ location when the holotype was collected and examined by the author when the holotype was selected.
What are topotypes?
Any specimens collected at a later date at the ‘type locality’ (the location where the holotype or syntypes were collected).
What does Bergmann’s Rule state?
Geographic races of endotherms tend to possess smaller body sizes in warmer portions of their range and larger body sizes in cooler climates.
What is the corollary to Bergmann’s Rule?
Geographic races of ectotherms tend to possess larger body sizes in the warmer portions of their range and smaller body sizes in cooler climates.
What does Allen’s Rule state?
The extremities of endotherms tend to be longer in warmer areas and shorter in cooler areas.
What does Gloger’s Rule state?
Geographic races of endotherms tend to be darker in warm or humid areas and lighter in cooler areas.
What does Jordan’s Rule state?
Fish living in warmer waters tend to be smaller and have fewer vertebrae than fish living in cooler water.
What does the ‘clutch-size’ rule state?
Geographic races of birds in warmer areas tend to have fewer eggs per clutch than races in cooler areas.
What are the two extant families of monotremes?
- Ornithorhynchidae
- Tachyglossidae
Are monotremes oviparous or viviparous?
Oviparous
Are monotremes ancestral to therians?
No
What type of valve do monotremes possess?
Incomplete right atrioventricular valve
What is lacking in monotremes that is important for complex thought?
Corpus callosum
What type of pectoral girdle do monotremes have?
Reptilian-like pectoral girdle
What is the name of the common opening for excretory and reproductive systems in monotremes?
Cloaca
How is sperm in monotremes described?
Reptile-like
How is the homothermic development in monotremes characterized?
Imperfectly developed
What type of chromosomes do monotremes possess?
Combination of macro and micro chromosomes
What unique skeletal feature do monotremes have?
Epipubic bones
What is the dental characteristic of adult monotremes?
No teeth (edentate)
What do male monotremes have on their rear ankle?
Horny-like spurs
What unique feature does the duck-billed platypus have?
Venom gland on spur
Which side of the reproductive tract is functional in monotremes?
Left side
What is a Protective shelled egg called
Cleidoic egg
What type of yolk placement do monotremes exhibit?
Meroblastic - placement of yolk to side
What type of young do platypuses have?
Altricial
Altricial young are born blind and underdeveloped.
What characterizes precocial young?
Well developed
Precocial young are more developed at birth compared to altricial young.
Define nitifugous.
Not tied much to natal site
Nitifugous species tend to leave their birthplace shortly after birth.
What does nidicolous mean?
Tied to nest for prolonged time
Nidicolous species remain in their nest for an extended period.
What term describes young platypuses?
Nidicolous
Young platypuses are tied to their nest for a prolonged time.
How many abdominal mammary glands do platypuses have?
Two
Platypuses have two abdominal mammary glands but lack nipples.
What is a unique feature of platypus nursing?
Pseudo nipple
The fur forms a tuft that acts as a pseudo nipple for young to nurse from.
How much higher is the iron content in milk from a platypus or echidna compared to other mammals?
60% higher
The milk from these species is significantly richer in iron.
What family do echidnas belong to?
Tachyglossidae
Tachyglossidae is the family name for echidnas.
What is the diet of Tachyglossidae species?
Myrmecophagus
Myrmecophagus species primarily feed on ants and termites or colonial insects.
What type of eater is a platypus?
Semi-aquatic omnivore
Platypuses have a diverse diet that includes both aquatic and terrestrial food.
Where did marsupials evolve before migrating to Australia?
South America
Marsupials migrated across Antarctica to reach Australia.
What percentage of marsupials are found in Australia?
Over 50%
However, Australia only makes up 6% of the world’s land area.
True or False: All marsupials have a pouch.
False
Not all marsupials have a pouch.
What is the typical direction that a marsupial pouch opens?
Front
In some species, such as wombats, the pouch opens to the back.
Fill in the blank: The marsupial dentition formula is _______.
5/4, 1/1, 3/3, 4/4 = 50
This indicates a larger dentition formula compared to Eutherians.
How do marsupial reproductive stages differ from Eutherians?
Marsupials have dynamic alternative reproductive stages
The longest pregnancy in marsupials is only a few weeks.
What is a significant aspect of marsupial development?
Long development occurs mostly in lactation
Eutherians spend a significant amount of time in gestation.
How many different age class offspring can marsupials have at one time?
Three
Eutherians typically have only one age class offspring at a time.
What is the maximum weight of a marsupial at birth relative to its mother’s weight?
Less than 1% of mother’s weight
This highlights the small size of marsupial offspring at birth.
What is the primary reason for the limited adaptability of marsupials compared to eutherians?
The need for claws and arms to access the pouch limits structural diversity and size.
This structural limitation affects how marsupials can adapt to different environments.
How many orders of magnitude do marsupials span?
4 orders of magnitude.
How many orders of magnitude do eutherians span?
7 orders of magnitude.
What is a unique skeletal characteristic of all mammals?
All mammals have a singular lower jawbone, known as the dentary bone.
In other groups, the jawbones are stitched and fused together.
What unique feature do mammals have regarding their skull?
2 articulating occipital condyles on the skull.
How many ossicles are found in the middle ear of mammals?
3 ossicles: malleus, incus, stapes.
What is a unique soft anatomical feature of all mammals?
All mammals have hair at some point in their life.
What type of heart do mammals have?
A 4-chambered heart with a left aortic arch.
What characteristic do enucleate erythrocytes have?
They lack a nucleus, allowing them to carry more oxygen.
What unique muscular structure do all mammals possess?
Muscular diaphragm.
What is heterodont dentition?
Possessing teeth of different types
Examples include incisors, canines, premolars, and molars which have different structures and functions.
What is the first tooth seen in early mammals?
Tribosphenic molar
This type of molar is characterized by having 3 points.
What is a quadritubercular molar?
A modern day tooth with 4 points
Represents an advancement in molar structure.
What defines a zalambdont tooth?
A tooth where a ridge forms a v-shape
This shape is distinct among different tooth types.
What is a dilambdant tooth?
A tooth with a w-shape
This is another variation in tooth morphology.
What does diphyodont mean?
Two sets of teeth in your life
This is typical for most mammals.
What is the definition of polyphyodont?
Multiple sets of teeth in your life
Found in some species that continuously replace teeth.
What is a hypsodont tooth?
High crowned tooth, common in herbivores
Adaptation to wear from grinding plant material.
What characterizes a brachydont tooth?
Low crowned tooth, typical in meat eaters
Suited for a diet that requires less grinding.
What is a bunodont tooth?
Rounded crushing tooth, found in omnivores
This type of tooth is versatile for varied diets.
What defines a lophodont tooth?
Cusps form ridges, characteristic of herbivores
Helps in grinding tough plant materials.
What is a selonodont tooth?
Cusps form crescent shapes, found in deer and herbivores
Adapted for effective grazing.
What is sectorial dentition?
Carnassial dentition involving the 4th upper premolar and the first lower molar, scissor-like structure
This type of dentition is characteristic of carnivores.
What is the dental formula for marsupials?
5/4, 1/1, 3/3, 4/4 = 50
The numbers represent the types and counts of teeth in marsupials.
What is the dental formula for eutherians?
3/3, 1/1, 4/4, 3/3 = 44
This formula outlines the teeth structure in eutherian mammals.
What is hair primarily made of?
Keratin
Hair is a dead material composed mainly of the protein keratin.
What are the three layers of hair?
- Medulla
- Cortex
- Cuticle
Each layer has distinct properties: medulla can be hollow or solid, cortex is densely packed cells, and cuticle has a scale-like outer covering.
What is the function of the pelage?
Insulation
Pelage refers to the entire coat of hair on mammals, which serves primarily for insulation.
What are the two color groups of pigments in hair?
- Melanins
- Xanthophylls
Melanins are responsible for blacks or browns, while xanthophylls contribute reds or yellows.
Fill in the blank: Blubber is an insulating material found in _______.
whales
Blubber serves as a thick layer of fat that provides insulation in marine mammals.
How do large mammals use fat for insulation?
By increasing body size
Larger body size in mammals helps retain heat and provides insulation.
What are some examples of protective coloration?
• Camouflage
• Defense
• Countershading
• Alert or warning
What is camouflage?
A method that allows an organism to blend into its environment.
What is countershading?
A type of coloration where the upper parts of an animal are darker than the lower parts.
What is alert coloration?
A warning coloration that signals danger or toxicity to potential predators.
What is albinism?
A genetic condition resulting in the complete loss of pigment.
What is melanism?
A genetic condition characterized by an overabundance of melanin pigments, resulting in a near black or all black appearance.
What is leucism?
A genetic condition that leads to a reduction of pigments in all or part of the body.
What are the two basic types of hair?
- Vibrissae
- Body hairs
What are vibrissae?
Specialized hairs with follicles that contain erectile tissue, primarily used for sensing.
What is the primary function of body hairs?
Protection and insulation.
What are the two basic categories of body hairs?
- Guard hairs
- Under hairs
What are guard hairs?
- Spines
- Bristles (e.g., mane of horse)
- Awns (over fur)
What are under hairs?
- Wool
- Fur (short fine)
- Velli (embryonic hair)
