The History of Evolutionary Thought. Biological definition of a species A group of populations whose...
-
Upload
antonia-york -
Category
Documents
-
view
216 -
download
0
Transcript of The History of Evolutionary Thought. Biological definition of a species A group of populations whose...
The History of Evolutionary Thought
Biological definition of a species
• A group of populations whose members are capable of interbreeding and producing fertile offspring.
Isolating Mechanisms
•Behavioral
•Geographic
•Temporal
THE PROCESS OF SPECIATION
Sciurus aberti kaibabensis Sciurus aberti aberti
Allopatric speciation – Geographic Isolation
Sympatric speciation (not geographically isolated)
These 2 species of toads are similar but are (somewhat) reproductively isolated by different mating seasons.
Fowler’s toad(Bufo fowleri)
American toadBufo americanus
Pre-or postzygotic???
Sympatric Speciation These 2 species of meadowlarks look alike but do not
sing the same song
Eastern Meadowlark(Sturnella magna)
Western Meadowlark (Sturnella neglecta)
Pre- or Postzygotic?
Aristotle (384-322 B.C.)
• Ladder of Life» 2 types of animals –
those w/ blood & those w/o
• Animals classified by their way of life
• Plants by structure
• Observation of various marine life anatomy was remarkably accurate
• Distinguished whales from dolphins
•Linnaeus was classifying organisms based on what they looked like.
•This made it difficult to classify organisms that seemed to share characteristics with both kingdoms that Linnaeus proposed, Plants and Animals.
• For example, fungi including mold and mushrooms do not move (or do they?) so they seem to be plants but, unlike plants…..?????
Lion Cat Dog Man Catbird
Phylum Chordata Chordata Chordata Chordata Chordata
Class Mammalia Mammalia Mammalia Mammalia Aves
Order Carnivora Carnivora Carnivora Primata Passeriformes
Family Felicidae Felicidae Canidae Hominidae Minidae
Genus Felis Felis Canus Homo Dymetella
Species leo domesticus carolinensis sapiens familiaris
Homologous Structures
• Structures that have different mature forms in different organisms but develop from the same embryonic tissues.
BATWHALE
HORSE
CAT
MAN
Analogous Structures
• Structures that have same function in different organisms but the organisms are not closely related and the structures are not closely derived.
Chordate Characteristics
1.Dorsal hollow nerve cord2.Notochord3.Postanal tail4.Pharyngeal pouches (Gill slits)
Plica luminaris
Arrector Pili
coccyx
Human Vestigial Stuctures
Classifying organisms often starts at the cellular level
Cladistics (phylogeny)
A system of classification based on the study of evolutionary relationships/ history of groups of organisms.
legs
internal fertilization
produce milk
placenta
An Example of Cladogram Construction for VertebratesOutgroup(lobed-finned fish)
Trait Turtle Kangaroo Mouse Human
Dorsal Nerve Cord
Yes Yes Yes Yes Yes Yes
Legs NO Yes Yes Yes Yes Yes
Nature of Egg
Requires water
Requires water
Hard shell prevents drying
Develops inside the
mother
Develops inside the
mother
Develops inside the
mother
Nature of development
In egg In egg In egg Marsupial Placental Placental
Hair No No No Yes Yes reduced
Presence of pouch
No No No Yes No No
Bipedal posture
No No No Yes No Yes