Lecture 2- Vertebrate Origins And Evolution Flashcards
What is ontogeny?
> ontogeny refers to the embryonic development of an organism as well as any development changes that occurs after birth or hatching (I.e., reproductive maturation, aging, etc.)
Summarize Von Baer’s Law.
> features that develop earliest in ontogeny are the oldest phylogenetically
features that develop later in ontogeny are more recent phylogenetic developments
features common to all members of a major taxonomic group develop earlier in ontogeny than do special features that distinguish subdivisions of the group
What is teleology?
> the idea that characteristics develop because they are needed
EXAMPLE: birds are needed to fly, so they developed wings
What are the components of the synthetic theory of evolution?
> organic evolution
genetic diversity
theory of natural selection
Summarize organic evolution
> organisms living today are not necessarily the same as those that lived in the past
organisms living in the past are not necessarily the same as those living today
based primarily on fossil record
Summarize genetic diversity
> all members of a population demonstrate genetic variation (identical twins may be an exception)
sources of genetic variability:
» sexual reproduction:
»» meiosis (independent assortment and crossing-over)
»» recombination (fertilization)
» mutation
The theory of natural selection was co-developed independently by whom?
> Charles Darwin
» published “On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life;” 1859
Alfred Russel Wallace
What are the components of the theory of natural selection?
> genetic variability exists in sexually reproducing populations
> some members of the populationn may be better “fit” for a given environment than others
> these individuals have a better chance of survival and of having fertile offspring
> the genotype a of these individuals will become more frequent in a population over many years
> if the environment does not change, then the population may achieve genetic equilibrium, and evolution may take place very slowly or not at all
What theory was developed by Jean Baptistery Lamarck?
> theory of acquired characteristics
The theory of acquired characteristics was developed by who?
> Jean Baptiste Lamarck
What are the components of the theory of acquired characteristics?
> during its lifetime an organism may develop an atomic changes in response to specific pressures it encounters
these acquired characteristics may then be passed on to its offspring
Summarize analogy, a term relating to origins and comparative anatomy.
> similarity in function in structures in two or more different species
> although the function in similar (I.e., wing of bird and wing of insect), neither the anatomy nor the embryological development is similar
> structures that are similar in function but that do not have a similar anatomical structure and/or embryological development are referred to as being analogous (noun = analogue). Organisms possessing these structures do not derive these structures from a common ancestor
Summarize homology, a term relating to origins and comparative anatomy.
> structural similarity uniquely evolved (due to inheritance) from a common ancestor or developed from a common embryonic a late.
> anatomy and development are similar, but function does not have to be similar
> of greater interest in this course are those structures found in different organisms that are similar in their anatomical structure and embryological development and that may or may not be similar in function
> such structures are referred to as homologous (noun= homologous)
> these structures are derived from an ancestor common to all organisms possessing these structures
> an example to be considered later are the set of middle ear bones in the human ear an certain elements of the upper and lower jaws found in fishes
Define homoplasy.
> structural similarity in different organisms not due directly to inheritance from a common ancestor or development from a common embryonic anlage
Define parallelism
> independent development of similar characteristics in lineages that inherit from a common ancestor a potential for such development but do not directly inherit the similar characteristics
Define convergence
> independent development of similar characters in two or more lineages even though they receive from the common ancestor neither the adaptations involved not characteristics that channel the development of those adaptations
Summarize paedomorphosis.
> larval form does not metamorphose > larval form becomes the adult form > larval form develops gonads and becomes sexually active > example: >>> amphioxus
Summarize neoprene
> type of paedomorphosis
adult form retains one or more larval characteristics
example:
» external gills in salamander such as Necturus (
The earth is thought to be over ________ billion years old?
> four
The appearance of vertebrates in the fossil records began almost _________ hundred million years ago?
> five
What are the geological subdivisions of the earth’s history?
> eons
» Precambrian eon (4.5 billion to 570 million years ago)
»» earliest life forms may have originated about 3.2 billion years ago, but there were no vertebrates during this eon
» Phanerozoic eon (began about 570 million years ago)
subdivisions of eons
» eras
» periods
» epochs
What are the subdivisions of eons?
> eras
periods
epochs
The quaternary and tertiary periods occurred during what era of the Phanerozoic eon?
> Cenozoic era (65 million years in duration)
The Cretaceous, Jurassic, and Triassic periods occurred during what era of the Phanerozoic eon?
> Mesozoic eon (165 million years in duration)
The Permian, Carboniferous, Devonian, Silurian, Ordovician, and Cambrian periods occurred during what era of the Phanerozoic eon?
> Paleozoic era (340 million years in duration)
Name the period and era of the Phanerozoic eon that the Holocene and Pleistocene epochs belong to
> quaternary (period)
> Cenozoic (era)
Name the period and era of the Phanerozoic eon that the pliocene, Miocene, Oligocene, Eocene, and Paleocene epochs belong to
> tertiary (period)
> Cenozoic (era)
What major event occurred during the Cambrian period of the Paleozoic era of the Phanerozoic eon?
> first appearance of vertebrates in the form of armored ostracoderms
What major event occurred during the ordovician period of the Paleozoic era of the Phanerozoic eon?
> ostracoderms only vertebrates, but armor disappearing; fishes became more active swimmers
What major event occurred during the Silurian period of the Paleozoic era of the Phanerozoic eon?
> appearance of primitive jawed fishes
What major event occurred during the Devonian period of the Paleozoic era of the Phanerozoic eon?
> fishes were the dominant vertebrates but amphibians began to appear
What major event occurred during the Carboniferous period of the Paleozoic era of the Phanerozoic eon?
> amphibians are abundant and reptiles began to appear
What major event occurred during the Permian period of the Paleozoic era of the Phanerozoic eon?
> reptiles became the dominant vertebrates
What major event occurred during the Triassic period of the Mesozoic era of the Phanerozoic eon?
> first dinosaurs appeared along with turtles and marine reptiles
What major event occurred during the jurassic period of the Mesozoic era of the Phanerozoic eon?
> reptiles dominant
What major event occurred during the cenozoic era of the Phanerozoic eon?
> all modern families and most modern genera of mammals present by end of era