Introduction chap. 1 Flashcards
Anatomy
The study of the structure of organisms (means to cut up)
Comparative anatomy
the study of similarities and differences in the anatomy of different species
Functional morphology
the relationship between the form and the function of tissues, organs, or organ systems within organisms
In terms of functional morphology, form is coupled with ______ and ______ _______.
Function , biological role
What are the 4 reasons to study comparative anatomy?
- provides a deeper understanding of our human anatomy
- helps to resolve evolutionary relationships through phylogenetic trees
- provides insights into modern vertebrate species’ origins, evolution, and design
- anatomy of modern species helps infer biological processes in extinct species
primitive
The original condition of that trait in the common ancestor
derived
indicates a notable change from the original condition (modification of a primitive trait)
what is an example of a primitive trait?
vertebral column, body hair, three-part brain
If the primitive trait is hair, what could be the derived trait?
quills, feathers, coloration in hair, hair texture
T/F: mammals can look similar without being closely related to one another
True. Mammals can look similar due to environmental conditions.
homologous structure
structure found in two or more organisms that are derived from a common ancestor (shared)
In a homologous structure, can it have a similar anatomical position but not serve the same function?
YES
T/F: homologous structures are used to investigate phylogenic relationships and construct trees
TRUE
analogous structure
structure found in two or more organisms that look similar and is used for the same function, but have evolved independently
an analogous structure is produced through _______ ________?
convergent evolution
convergent evolution
Unrelated species independently evolve similar traits via adaptation to similar environments with similar selective pressures
exaptation (preadaptation)
a pre-existing structure that is inherited from an ancestor but is used for an unrelated function.
what is an example of an exaptation?
feathers were originally evolved for thermoregulation, but are now used for flight.
what is the phrase that describes evolutionary change involving continuous modification of ancestral structures?
descent with modification
systematics
the scientific study of the kinds and diversity of organisms and of any relationships among them
systematic includes both __________ and __________
taxonomy, phylogenetics
taxonomy
discovering, describing, and naming organisms
phylogenetics
determining the evolutionary relationships among organisms
binomial nomenclature
system of nomenclature in which 2 terms are used to denote an extant and extinct species
what do the first and second terms indicate in binomial nomenclature?
the genus and the specific epithet
phylogeny
the study of evolutionary relatedness among past and present taxonomic groups (relationships among living things through time)
what is phylogeny visualized as?
evolutionary trees
taxon
a named unit at any level of the hierarchy
T/F: at each level/rank, a taxon is placed into a more inclusive group
True
cladistics
a system of biological classification in which organisms are categorized based on SHARED DERIVED CHARACTERISTICS that can be traced to a group’s most recent common ancestor.
synapomorphies
shared derived trait found in two or more taxa that are used to infer a phylogenic relationship
who proposed the idea of cladistics?
entomologist Willi Hennig
character
heritable attribute used for recognizing, differentiating or classifying taxon
symplesiomorphy
a shared primitive trait that is relatively unchanged from the ancestral form (not informative about relatedness)
autapomorphy
a derived trait that is unique to only one group (not informative, tells ys nothing about relatedness)
homoplasy
a derived trait found in two or more taxa that did not arise from a common ancestor
T/F: Primitive traits are NOT informative
TRUE!
T/F: derived traits ARE informative
True
cladogram
branching diagram showing the evolutionary relationship between taxa
clade
natural evolutionary lineage that includes the most recent common ancestor and all and only its descendants
a clade forms a _______
monophyly
monophyly
a complete clade that consists of the most recent common ancestor and ALL of its descendants
paraphyly
an incomplete clade that includes the most recent common ancestor but NOT all of its descendants
what is an example of paraphyly?
“fishes”
sarcopterygian fishes gave rise to tetrapods(amphibians, reptiles, mammals, and birds
polyphyly
an artificial clade composed of unrelated organisms descended from more than one ancestor (containing misleading convergent or homoplastic traits)
sister taxa:
groups of organisms that share an immediate common ancestor and hence are each other’s closest relatives
crown group
includes the most recent common ancestor of all living taxa of a particular group(plus any extinct descendants)
stem group
includes extinct taxa related to but not part of the crown group
total group
includes both the crown group and the stem groups
stem mammals
those taxa in lineages leading to but derived before the mammalian crown group (includes pelycosaurs, gorgonopsids, and cynodonts)
protomammals
Went extinct but gave rise to all living mammals today
isometric growth
All structures of an organism have the same rate of growth so that its shape is consistent throughout ontogeny
allometric growth
certain structures of an organism have differential rate of growth in an individual throughout history
as a species increases in size, its ______ and ______ _____ do not increase at the same rate.
volume, surface area
T/F: volume and amass increase faster than the surface area with an increase in overall size, thus supportive bone must become more robust
TRUE
Because volume and mass increase disproportionately with surface area, larger organisms must have _______ _________ to allow for adequate ________ _________.
morphological specializations, physiological exchange
heterochrony
evolutionary change in the timing or rate of developmental events in the descendent species when compared to ancestral condition, leads to changes in size and shape
paedomorphosis
juvenile characters of ancestors appear in adults of descendants
progenesis
acceleration of reproductive development relative to somatic development when compared to ancestral condition
neoteny
slowing down of somatic development relative to reproductive development when compared to the ancestral condition
peramorphosis
adult somatic characters of descendants are exaggerated in shape when compared to that of ancestors
acceleration
rate of development of a somatic structure increased compared to the ancestral condition
hypermorphysis
offset in the developing somatic structure is delayed compared to the ancestral condition
