FINAL TERM Flashcards
are different in
appearance and perform different
functions but are built on the same basic
pattern and have a common origin
(same source)
Homologous organs
the similarity in the basic structure of
organs of different animal groups based
on common ancestry or origin from
some common structural patterns
Homology
Similarity in the DNA sequences found in
different species
Existence of universal genetic code, the same 64 codons specify the same amino acids from
bacteria to man
Similarity in the structure of plasma membrane
Similarity in the mechanism of transcription and translation via same RNA polymerase
Use of ATP as energy currency
Similarity in the mechanism of DNA replication via DNA polymerase
Genetic homology
- is seen in the overall
process of development, form of the embryos of different groups and fate of particular embryonic tissues or organs.
Developmental homology
are similarities in adult
morphology in organisms of different groups and are the results of homologous genes .
Structural homology
Levels of homology in species
Genetic, developmental, and structural homology
Types of homology
Phylogenetic, Sexual, Serial, and Molecular homology
is similarity among animals or
among plants of different species. Ex: homology in the
hand of man and forelimbs of horse and bat)
Phylogenetic homology
is parallelism in the male and female
reproductive organs of the same species.
Sexual homology
has been observed among
invertebrates .
Serial homology
is similarity in the biomolecules,
such as DNA, the genetic material found from viruses to man.
Molecular homology
when the ancestral individuals of the same group migrate to different habitats, their organs undergo adaptive modifications in different environments and become different in form and/or function.
Divergent evolution
have almost similar appearance and perform the same function but they develop independently in totally different groups through parallel evolution and are not inherited from a common ancestor
Analogous or homoplasious organs
is the superficial similarity in appearance between organs of different animal groups because they carry out the same function.
Analogy
Organisms of the same or closely related groups when occupy different habitats, they assume different appearances and their homologous structures exhibit great divergence in the form and function.
Adaptive divergence
Organisms of distantly related or totally
unrelated groups are found to develop similar
adaptations, while living in the same or similar
habitat. Their analogous structures, though
apparently similar are constructed on different
basic plans
Adaptive convergence
Used the term “vestiges” and “Rudiments”
Jean Baptiste Lamarck
Used the term Rudimentary Organs
Charles Darwin
Popularized the term “Vestiges”
Robert Wiedersheim
Group 1 Presentation Title
Vestigial Structure in Postcranial Skeletons of Extant Mammals
Group 2 Presentation Title
Vestigial organs as opportunities for functional innovation the example of the penstemon staminode
structures that persist within a species but have lost their function
Vestigial structures
They are usually smaller than their homologues
in other species, and are sometimes described as
Atrophied
often modifies the androecium, resulting in either stamen loss or transformation of stamen
function from pollen production and
presentation to alternate functions
Floral evolution
stamens that have lost their primary
function of pollen production
“abortive stamen”
relatively uncommon, but widely
distributed taxonomically
32.5% of angiosperm families and 54.4%
of angiosperm genera.
Staminode
arise as intermediate structures during
reductive processes in the androecium.
decreases in stamen number typically
involve progressive suppression of
stamen development during
morphogenesis
Nonfunctional staminodes
commonly implicated staminode roles
include pollinator attraction through
visual conspicuousness and/or provision
of attractants and rewards, avoidance of
selfpollination, and facilitation of pollen
removal and receipt through various
trigger mechanisms
Functional staminodes
occurs when stamens initially serve
purposes in addition to pollen
production and presentation (e.g.,
pollinator attraction)
functional constraints should favor
‘‘division of labor’’
Direct evolution
the nonfunctional phase preceding
adoption of a new function allows
staminodes to assume novel functions
not expected of stamens
Indirect evolution
Beardtongue in English
the largest genus of flowering plants
endemic to North America (250 species;
Holmgren 1993)
Penstemon (Scrophularicaeae)
staminode hinders pollinator access to
nectar, increasing visit duration and
contact with sexual organs, thereby
increasing pollen receipt by stigmas and
controlling pollen removal from anthers.
the staminode acts as a lever that
enhances stigma contact with the
pollinator, so that staminode removal
reduced pollen receipt, but did not
affect pollinator attraction, visit
duration, or pollen removal.
Bee-pollinated
staminode removal from hummingbird pollinated species did not affect any measured aspect of pollination,
indicating that the staminode serves no
function in this derived pollination
system
Hummingbird- pollinate
Group 3 Presentation Title
VESTIGES OF THE NATURAL HISTORY OF
DEVELOPMENT - HISTORICAL HOLDOVERS REVEAL THE DYNAMIC INTERACTION BETWEEN ONTOGENY AND PHYLOGENY
evolution of biological
systems’ two main stages:
Evolutionary and Developmental change
Vestiges come from the Latin word “vestigium” which means
Footprint
what are the human vestiges
Vermiform appendix
tail bone (coccyx)
Wisdom tooth
He published “Vestiges of the Natural History of Creation”
Robert Chambers
is present in humans but in much-reduced form relative to other mammals. It is series of
physiological changes that take place in
the body in response to a mammal
holding its breath while submerged in
water
Mammalian dive
are a vestigial motor reflex pattern (of
glottal closure during inhalation, so that
the vocal folds slam shut) left over from
early tetrapod vertebrates, specifically
the tadpole larvae of amphibians
Hiccups
This bird is endemic to Fernandina and
Isabela Islands of the Galápagos
Archipelago, provides an excellent
example of vestigial attributes due ot its
noticeably stumpy, stubby wings that
are much too small to allow it to fly
flightless cormorant (Phalacrocorax harrisi)
reflex vestige of human babies
from ancestral primates, where offspring
needed a firm grasp of their mothers’ fur as they were carried
Palmar gasp
