Lectures 2-4 Flashcards by John Pate

Ontogeny

EMbryonic development of an organism after birth (reproductive maturation)

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Teleology

Characteristics develop out of need, untestable…birds needed to fly so developed wings.

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Von Baer’s law

Features that develop earliest in ontogeny are the oldest phylogenetically and features that develop later are more recent development. Not exactly true…

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Synthetic theory of evolution [3 components]:

Organic evolution, Genetic diversity, and natural selection….Ernest Meyer

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Organic evolution

Based on fossil record, organisms today aren’t same as prior in Hx. Based on fossil record

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Genetic diversity

All members of population demonstrate genetic variation d/t sexual reproduction (meiosis/recombination) and mutation

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Natural selection

Co-developed by Alfred Wallace and Darwin. Those w/ best chance survival have better chance fertile offspring; thus there genotypes will become more frequent in population over years

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Theory of acquired characteristics and author:

Jean Baptiste Lamarck- AN organism can develop anatomical changes in response to specific pressures it encounters. Ex: blacksmith strength

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Analogy

Similarity in function, but different in anatomy/embryological development. Ex: dolphin and carp have similar functions for limbs…differ in structure though

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Homology

Similarity in structure but different function [d/t inheritance from common ancestor]. Ex: lizard and dolphin limbs similar in structure differ in function-did have common ancestor.

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Homoplasy

Structural similarity in different organisms not d/t inheritance from common ancestor

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Convergence

Gaining similar characteristics by species w/ different ancestors..ex: Dolphin, shark, and icthysaur all have similar body from same ancestor..maybe d/t environment

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Parallelism

Common ancestor and independently gains characteristics…ex: Long feet and bushy tail mice common ancestor and both developed these characteristics

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Paedogenesis and the origin of vertebrates:

The hypothesis is that larval tunicates have the tail intact and became able to reproduce…so the tunicates gave rise to cephalochordates and vertebrates

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First vertebrates appeared in which period, how long ago was this?

Cambrian; 570 million years

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Characteristics of hypothetical common ancestor Echinoderms and chordates?

Most agree chordates have more in common w/ Echinoderms.
Characteristics:
Sessile/semi-sessile
Deuterostomous 
Bilateral symmetry
Ciliated larval form
Lophophorates-can draw in water
Ciliary feeders

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Major anatomical characteristics of Amphioxous

Larval form similar to adults but no gonads.
Lack paired limbs and jaws
No vertebral column
Nerve cord dorsal to notochord but no brain
Lacks cartilage and bone
V shaped muscle segments and used for swimming
Mouth opens to pharynx
Endostyle located in floor pharynx to trap food particles and move them to intestines. Thought to be development of thyroid.

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MAjor characteristics of urochordates

Sessile bag of fluid; w/ 2 hoses [incurrent siphon to pharynx w/ filtration slits & intestine and atriopore to excurrent siphon] CELLULOSE-like polysaccharide-tunicin-unheard of animal kingdom. Dermal epithelium and connective tissue -mantle; use ciliary action to draw water into pharynx through incurrent siphon. MEtamorphosis from tadpole-like larval stage. Larva head adheres to substrate “home” and tail collapses removing notochord and most of nerve cord.

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Adult Urochordata vs. larva

Adult has no notochord or nerve cord…has gonads and ganglion though

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Clade

Monophyletic group made up of an ancestor and all of its descendants

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Cladistics:

The study of clades [monophyletic group made up of common ancestor and all its descendants]

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Synapomorphies:

Derived characters that are shared by several lineages

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Paraphyletic:

Includes a common ancestor and some but not all of its descendants.

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Polyphyletic:

Includes descendants but not the common ancestor

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Cladogram:

A diagram that shows a sequential hypothetical EVO. Branching pattern of a group of clades.

5 classes of fishes and give examples

Agnatha, Acanthodii, placodermii, Chondrichthyes, and Osteichthyes

Agnatha:

W/o jaws and paired appendages- ostracodermi and cyclostomata

Acanthodii

Streamlined body 1st of the jawed fishes- gnathostomes

Placodermi

1st jawed fishes in Gnathostomes: movable joint btw head shield and trunk. Paired pectoral and pelvic fins

Chondrichthyes

Shark, skates, Ray-no bone cartilage only

Osteichthyes

Paired fins, internal fin skeleton...made of bone

Ostracodermi

Oldest known vertebrates (570 my)..all extinct. During the Cambrian period. LAcked paired appendages and jaws. Pharyngeal pumping mechanism to draw in currents of water, dermal armor. Prey not predator

Cyclostomata

Lacked jaws and paired appendages. More predator like..had pineal gland.round mouth.constant water cycle through mouth.

Anadromous

Larval grow in freshwater as filter feeders then move into marine environment becoming predators [lampreys]

3 major development that set gnathostomes apart from earlier fish?

Jaws [development of] Appendages [paired] Buoyancy mechanism [lungs/swim bladder]- allows fish to not swim and remain still. Sharks don't have..

Major anatomical characteristic distinguishing sarcopterygians from actinopterygians?

Internal fin skeleton.. Sarco: cartilage/bone Actin: spines

WHich Paleozoic era did fishes first appear?

Cambrian 570 my

Significance of the 3 major morphological developments in gnathostomes:

Jaws: were hyostylic (gave rise to ours autostylic) Paired appendages: fins turned to feet Buoyancy mechanism: gave rise to lungs for terrestrial states

List the four classes of tetrapods

Amphibia, reptillia, Aves, Mammalia

Early Devonian tetrapods

Labyrinthodonts- placed as amphibian

What group is thought to have gave rise to modern amphibians ?

Temnospondyls during the early Carboniferous

Characters of modern amphibians

Pedicellate teeth, Cylindrical vertebral centra, and 2 auditory ossicles-----salamanders

Characters of devonian Tetrapods

Devonian tetrapods represent transition from fish to land animal....tail w/ fin rays, begin to develop breathing nostrils, lungs well-developed, tougher skin, inner ear for sound in air not sound in water

3 orders of amphibians

Caudates, Anurans, and apodans

Caudates

"Have a tail" includes salamanders

Anurans

"Lacking a tail" frogs/toads

Apodans

"Lacking limbs" caecilians-wormlike

Anapsids:

No arch in the skull: 2 types--- | Cotylosaurs and Chelonia

Which one of the anapsids is stem reptile for all other reptiles?

Cotylosaurs: Resembled seymourian tetrapods, May have been several feet in length, dermal armor, skulls more laterally flattened rather than dorsoventrally as in amphibians

Distinguishing feature btw 2 grps of dinosaurs?

Pelvic girdle: Ornithischians-tetraradiate pelvic girdle (bird hipped) Saurischians- Triradiate (lizard hipped)

3 subgroups of modern lepidosaurs and skull differences:

Diapsid: 2 lateral openings behind orbit---sphenodon Lizards: Lack Lower arch ventral to lower opening. Snakes: lack the bony arch seperating the 2 openings

Why do dinosaurs form paraphyletic group?

It includes the ancestor of birds and dinosaurs but doesn't include the birds

Reptilian characteristics in early birds:

Bony tail; separate fingers w/ claws; teeth

Theory of flight for birds:

Probably evolved from bipedal archosaur- flight may have evolved d/t: Thermal insulation, Insect-catching, better pursuit of prey/escape, allowed to roost in trees

Earliest group of synapsids

Pelycosaurs

Characteristics shared by mammals and advanced therapsids:

``` Secondary palate, Enlarged Dentary bone, Teeth and rib differentiation, Legs pulled in, illium extends forward, Elongated sacrum, feet well-developed,mandible jaw articulation ```

Mammal characteristics:

``` Live birth, Endothermy, Resp. Diaphragm, 4 chamber heart, Neocortex, Double occipital condyle, Mandible single bone, Bony secondary palate Loss of interclavicle Hair.fur Mammary glands ```

Earliest mammals:

Morganucodonts

Morganucodonts dentition:

Heterodont dentition w/ tricodont molars

3 groups of Modern mammals

Monotremes: egg-laying mammals Marsupials: possum Placentals: placenta

List and describe requirements for terrestrialism:

Dessication control: not drying out-pituitary; Resistance to gravity: vertebra bony; Changes in organs-special senses: lateral line system-> hearing/eyes; Nitrogenous waste excretion; reproductive changes