Who are the Vertebrates?
http://www.emc.maricopa.edu/faculty/farabee/biobk/cladogram_1.gif
Where did Vertebrates come from?
://www.intechope
om/books/theygdala-a-discretetitaskingnager/amygdala-emotionalning-inebrates-amparativespective
How did they
get there?
Geologc Time
542MYA
A critical component to understanding
evolution, biodiversity, the structure and
biology of organisms, and ecological
interrelationships is:
TIME
It’s hard to grasp how much time has passed
since the earth was formed. A good analogy is
to make a movie of the entire history of the
earth. This movie will run for 30 days. You
can eat a lot of popcorn during the first 25
days, but don’t blink during the last few
minutes!
1
1 “day”
~ 150
MY
6
13
2
3
H A DE A N
4
5
E O N
First life?
7
8
Prokaryotic A
fossils
14
15
9
10
R C H E A N
16
17
11
12
E O N
18
19
PROTEROZOIC
20
27
21
22
Eukaryotic
fossils
23
28
30
29
24
EON
25
26
Multicellular
fossils
27
28
29
30
PALEOZOIC ERA
Aquatic
life and
invertebrates
dominate
Terrestrial
plants,
Aquatic
vertebrates,
amphibians
MESOZOIC
ERA
Coal
forests,
Insects
Birds,
flowering
plants
MESOZOIC
ERA
CENOZOIC
ERA
Reptiles
dominant,
mammals
Mammals
dominant,
humans: last
10 minutes
Event: Cambrian Explosion of Biodiversity
Age: ~ 540 mya
Time in Movie: Day 27
What is the Cambrian Explosion?
Variation Among Verterbrates
http://www.emc.maricopa.edu/faculty/farabee/biobk/cladogram_1.gif
Partitioning Phenotypic Variance
Phenotypic Variance (VP) = Genetic Effects (VE) +
Environmental Effects (VE) + V(GxE) + Verror
(Scheiner and Goodnight 1984; Via and Lande 1986)
Why are there different vertebrates?
http://www.whale.to/vaccine/wallace/1.html
Two young, British naturalists independently read Malthus’
essay in 1838
“Human population grew geometrically, at a rate faster than the rate of
increase in resource (food) availability, only the fittest (to compete for
the limited food supply) would survive.”
Charles Darwin (1809-1882)
http://www.calacademy.org
http://sandraoles.com
More Facts About
Darwin
▪Educated in Cambridge
▪ Naturalist on HMS Beagle in 1831
▪ collected, studied, stored
biological specimens
throughout South America
and South Pacific
▪ published “On the Origin of
Species by Natural
Selection” in 1859
HMS Beagle
Galapagos Islands
After the voyage
• Found that individuals struggled for existence
– Competition for:
• Food
• Space
• Predators
• shelter
Food
Shelter
Space
Finding mates
Predators
Descent with modification
• Every species – living or extinct – must
have descended by reproduction from
preexisting species
• That species in turn must be able to
change over time
Natural Selection
Plausible Processes Leading to
Descent with Modification
(Theory of Natural Selection)
• Overproduction
– More offspring produced than can survive
• Genetic Variation
– Within populations, individuals have different traits
• Struggle to survive
– Must compete for existence
• Differential reproduction
– Those with best adaptations are most likely to
survive and reproduce
Alfred.R. Wallace (1823-1913)
http://www.whale.to/vaccine/wallace/1.html
Evolution by natural selection (1858), independent of Darwin;
based on Malthus’ essay (1838)
“Human population grew geometrically, at a rate faster than the rate of
increase in resource (food) availability, only the fittest (to compete for
the limited food supply) would survive.”
Carl von Linne (1707-1778)
Linnaean classification:
Kingdom
Phylum
Class
Order
Family
Genus
species
http://www.encyclopedia.com
Binomial Nomenclature:
Carolus Linnaeus
Linnaean classification = this system groups organisms into ever smaller
and smaller groups (like a series of boxes within boxes, called a
nested hierarchy)
Animalia
(animals)
Plantae
(plants)
Fungi
(funguses)
Chordata
(vertebrates)
Mollusca
(snails, clams,
etc.)
Arthropoda
Coelenterata
(insects, spiders, (corals, jellyfish)
etc.)
Annelida
(segmented
worms)
Mammalia
(mammals)
Reptilia
(reptiles)
Aves
(birds)
Amphibia
(amphibians)
Agnatha etc.
(fish)
Primates
(primates)
Carnivora
(dogs, cats, and
seals)
Rodentia
(mice, rats,
squirrels, etc.)
Marsupialia
(opossums,
kangaroos, etc.)
Cetacea
Approximately 13
(whales, dolphins, others…
and porpoises)
Family
Hominidae
(humans and
apes)
Pongidae
(orangutans)
Hylobatidae
(gibbons)
Cebidae
(monkeys)
Lemuridae
(lemurs)
Genus
Homo
(humans)
Pan
(chimpanzees)
Gorilla
(gorillas)
Australopithecine
(extinct)
Species
sapiens
(100,000 BC)
neanderthalensis “archaic” sapiens erectus
(200,000 BC)
(400,000 BC)
(1.8 million BC)
Kingdom
Phylum
Class
Order
Protista
(protozoans)
Monera
(bacteria)
Approximately 16
others…
7 others…
habilis
(2.4 million BC)
http://members.cox.net/kdrum/Taxonomy.htm
Jean-Baptiste de Lamarck (1744-1829)
(National Museum of Natural History)
Evolution through
inheritance of
acquired
characteristics
http://picsdigger.com
http://rosshoneywill.com/2008/06/12/lamarcks-evolution
Lamarckian Evolution
http://vagitup.com/2011/06/15/arnies-kid/
http://www.popcrunch.com/68-celebrities-before-they-were-stars/
http://www.bodybuildbid.com/articles/mr
olympia/arnold-schwarzenegger.html
Richard Owen (1804-1892) – “Archetype” (biological blueprint)
http://www.taxidermy4cash.com/owen.html
His concept of the archetype
provided some explanation
for homologies.
Who are the Vertebrates?
Vertebrates belong to
the Phylum Chordata…
http://www.emc.maricopa.edu/faculty/farabee/biobk/cladogram_1.gif
What are Chordates?
The Chordate Body Plan
Endostyle or Thyroid?
Who are the chordates?
Dorsal = Chordin
Ventral = BMP
Dorsal = BMP (Bone Morphogenetic Protein)
Ventral = Chordin
Who are the Vertebrates?
Vertebrates belong to
the Phylum Chordata…
http://www.emc.maricopa.edu/faculty/farabee/biobk/cladogram_1.gif
EVOLUTION AS REMODELING
PREADAPTATION OR PROTOADAPTATION OR EXAPTATION
The form and function of a phenotype (i.e., structure, behavior, physiology) exists
before the biological role arises. Does change (evolution) in the trait
happen in anticipation of a biological role?
How similar are vertebrates?
Ancestry (Homology)
Function (Analogy)
Appearance (Homoplasy)
Homology
HOMOLOGOUS CHARACTERS = characters in different
organisms that are similar because they were inherited
from a common ancestor that also had that character.
Richard Owen (1804-1892) – “Archetype” (biological blueprint)
http://www.taxidermy4cash.com/owen.html
His concept of the archetype
provided some explanation
for homologies.
Analogy
ANALOGOUS CHARACTERS = characters that are
superficially similar because they evolved to serve the
same function, BUT, they have separate evolutionary
origins. Convergent Evolution.
Homoplasy
https://en.wikipedia.org/wiki/Diversity_of_fish
http://stevestonecoralreeffoundation.org/reefs/reefstoday7.html
Convergence of Design
(Analogy?)
Who are the Vertebrates?
Vertebrates belong to
the Phylum Chordata…
http://www.emc.maricopa.edu/faculty/farabee/biobk/cladogram_1.gif
What are Chordates?
The Chordate Body Plan
Endostyle or Thyroid?
The Animalia
SCHIZOCOELIC
ENTEROCOELIC
What are Chordates?
The Chordate Body Plan
Endostyle or Thyroid?
Who are the Vertebrates?
Vertebrates belong to
the Phylum Chordata…
http://www.emc.maricopa.edu/faculty/farabee/biobk/cladogram_1.gif
What are Chordates?
The Chordate Body Plan
Endostyle or Thyroid?
The Animalia
SCHIZOCOELIC
ENTEROCOELIC
What are Chordates?
The Chordate Body Plan
Endostyle or Thyroid?
The Notochord
Notochord = a slender rod
that develops from the
mesoderm in all chordates;
prevents collapse of the body,
and muscle contractions on
alternating sides efficiently
flex the body in swimming
strokes.
Dorsal Tubular Nerve Cord
Phylogenetic Relationships Within the “Protochordates”
Hemichordata, generalized acorn worm.
Hemichordates (hemi=half chordates) are marine worms with
apparent links to chordates and echinoderms.
Synapomorphy with chordates: pharyngeal slits.
Synapomorphy with echinoderms: tornaria larva of hemichordate
similar to dipleura larva of echinoderms; deuterostome embryology
Cephalochordata.
Branchiostoma lanceolatum
(amphioxus)
http://www.usm.maine.edu/bio/courses/bio2
05/amphioxus.jpg
The notochord extends to the rostral tip of the body, hence the name cephalochordate (head-notochord).
amphioxus
Body Size: ca 8 cm
Habitat: shallow sandy bottoms in
major oceans
Food Habits: filter diatoms and
other plankton via cilia to mouth
and pharynx and out through
atriopore; mucus is produced by
endostyle (functions in iodine
uptake; homologous to thyroid
gland)
Reproduction: males and females
swim up to the water column to
spawn in early summer
Life cycle: larvae planktonic for 2-5
months, then metamorphose; very
abundant (1000/m3); larvae and
juveniles undergo vertical
migrations; sexually mature in 2-3
years, benthic; adults live for 1-4
years.
Urochordata.
http://kentsimmons.uwinnipeg.ca/16cm05/1116/chordate.htm
http://www.oceanwideimages.com/images/7544/large/24M120509-strawberry-tunicate.jpg
Origin of the Chordates?
1. Chordate from Annelid and Arthropod Hypothesis
(Geoffroy Sint-Hillaire, 1822)
2. Chordates from Echinoderms Hypothesis
(Garstang’s Hypothesis)
Chordate from Annelid and Arthropod
Hypothesis; Geoffroy Sint-Hillaire, 1822)
http://image.tutorvista.com/content/animal-kingdom/phylum-annelida.jpeg
Chordate origins?
Molecular phylogeny of some animal clades, including the
vertebrates. Validity of the upside down arthropod /
annelid hypothesis ???
Chordates from Echinoderms Hypothesis. -Garstang’s Hypothesis.
http://www.bio.miami.edu/dana/pix/echinoderm_collage.jpg
Chordate origins?
Who are the chordates?
Dorsal = Chordin
Ventral = BMP
Dorsal = BMP (Bone Morphogenetic Protein)
Ventral = Chordin
So, who are the vertebrates?
The Vertebrata include all
animals with a segmented
vertebral column, a head
skeleton, tripartite brain, and
ectodermal placodes. Notice that
all of these have something to do
with advances in locomotion
(ectodermal placodes develop
into special sensory organs such
as equilibrium, hearing,
taste/smell, vision which
facilitate moving forward to find
things and not bump into things.
The development of the brain
allows for increased processing
of this sensory input. The head
skeleton provides a protective
shell for the sensory organs).
Innovations of the Vertebrates
(1) VERTEBRAL COLUMN
•http://www.nlm.nih.gov/MEDLINEPLUS/ency/imagepages/19469.htm
http://www.spineuniverse.com/displayarticle.php/article265.html
Innovations of the Vertebrates
(2) HEAD
http://www.human-anatomy.com/human-anatomy/sh202.htm
Innovations of the Vertebrates
(3) NEURAL CREST CELLS and EPIDERMAL
PLACODES: unique in vertebrates!
These special neural crest cells and placodes are the source of
adult structures that distinguish vertebrates from other
chordates!
cephalochordates
urochordates
hagfish
lamprey
gnathostomes
Who are the vertebrates?
Development of Vertebrates Proceeds from General to Specific:
Conservatism or Preservationism in Ontogeny
During early development, there is
considerable similarity among
vertebrate embryos followed by
increasing differentiation toward adult
stages; an interesting trend from
general to specific!
Some Functions of the Integument?
1.Resistance to mechanical injury
2.Barrier against pathogens
3.Maintains shape of an organism
4.Osmotic regulation
5.Gas and ion exchange
6.Thermoregulation
7.Holds sensory receptors
8.Holds feathers, hair, horns
9.Skin pigments
Early Development of the Vertebrate Integument
Gastrulatio
n
1. MORULA = a solid mass of cells formed
after several cell division (cleavage)
2. BLASTULA = a spherical mass formed by
blastomeres moving toward the periphery of
the mass, organizing into a layer of cells
surrounding a fluid-filled cavity called the
BLASTOCOEL
3. GASTRULA = marked by the formation of
the BLASTOPORE and ARCHENTERON (or
GASTROCOEL) during GASTRULATION
4. NEURULA = formation of the
ECTODERMAL TUBE, the NEURAL TUBE
(CNS forerunner!) and the enclosed cavity
called the NEUROCOEL during
NEURULATION
Neurulatio
n
Embryonic Development of the Skin (Neurulation)
1. Single-layered ectoderm produces
multilayered epidermis
2. Stratum basale (stratum
germinativum) rests upon the
basement membrane; replaces the
outer layer of cells called the
periderm
3. Dermis arises principally from the
dermatome
4. Stratum compactum = connective
tissue and ordered layer of collagen
fibers
5. Neural crest contribute to bony
armor and chromatophores
6. Nerves and blood vessels invade
the integument to round out its
structural composition
General Features of the Vertebrate Integument
Terrestrial Vertebrates: keratinized or cornified
layer (stratum corneum)
Keratinocytes → Keratinization → Keratin (protein)
hair, hooves, horn,
sheathes, callus or other
cornified structures
Specializations of the Vertebrate Integument
Skin Glands
Skin Derivatives in Vertebrates
Variation in Integument Functional Anatomy Among Vertebrates
Ostracoderms and Placoderms
(The First and Early Vertebrates)
Features:
1. Bony plates of dermal armor act as exoskeleton; Large, cranial
dermal bones form head shields; Dermal bones become smaller
posteriorly to form dermal scales.
2. Tubercles, made up of enamel and enamel-like substance over an
inner layer of dentin form the surface of these scales.
Hagfishes and Lampreys
Features:
1. Dermal bone is lost; scale-less skin.
2. Epidermis has lots of living epidermal cells, along
with unicellular glands (granular and club cells).
3. Dermis has layers of fibrous connective tissue and
pigment cells
4. Hagfish- skin has thread cells that release mucus and
multicellular slime glands that release slime to the
skin surface.
Chondrichthyes
Features:
1. Dermal bone is absent, but skin is covered with denticles (placoid
scales)
2. Secretory and epidermal cells are present in the epidermis
3. Dermis is made up of fibrous connective tissue, especially elastic
and collagen fibers
4. Placoid scale develops in the dermis but projects through the
epidermis
5. Chromatophores in lower epidermis and upper dermis
Osteichthyes (Bony Fishes)
Features:
1. Dermis = loose connective tissue
(upper layer) and dense fibrous
connective tissue (deeper layer)
2. Chromatophores found within the
dermis.
3. Scale is the most important
structural product of the dermis
4. Dermal scales do not pierce the
epidermis
5. Epidermis has basal and
epidermal layers of cells
(secretory and club cells). These
produce mucous cuticle, or
surface “slime.”
Types of Bony Fish Scales
Cosmoid scale (sarcopterygians)
= thick, layer of dentin (cosmine)
beneath a thin layer of enamel
resides upon two layers of bone
(vascular and lamellar)
Ganoid scale (primitive
acinopterygians, gars) = thick
surface coat of enamel (ganoin);
no dentin above dermal bone
Teleost scale is made of only
lamellar bone, acellular and
mostly noncalcified:
(1) Cycloid scale has concentric
rings, or circuli.
(2) Ctenoid scale has a fringe of
projections along its posterior
margin.
Amphibian Integument
Features:
1. Skin is involved in gas exchange
(Cutaneous Respiration) = capillary beds
in the lower epidermis and deeper dermis
2. Leydig cells in skin of larvae secrete
antibacterial and antivirus substances
3. Adults have no Leydig cells, but have
regionalized skin: strata basale,
spinosum, granulosum, and corneum
4. Two types of multicellular glands:
mucous (smaller) and poison glands
(granular glands; bigger) develop in the
dermis but empty into the surface via
ducts
Reptilian Integument
Features:
1. Keratinization more extensive and
less skin glands than amphibians
2. Epidermal scale (Scute) = fold in the
epidermis; no contribution from
dermis
3. Hinge = junction between scales
4. Gastralia = dermal bones in the
abdominal area
5. 3 regions of the epidermis: stratum
basale, stratum granulosum, and
stratum corneum
6. Molting / Ecdysis = removal of
extensive sections of superficial
epidermis: duplication of the deeper
layers of granulosum and corneum
occurs before this event
Integument in Birds
Features:
1. Feathers = nonvascular and
nonnervous products of
the epidermis and the
keratinizing system
2. Pterylae = distinctive tracts
of feathers
3. Uropygial Gland = skin
gland at the base of the tail
that secretes lipid and
protein products
4. Salt Gland = skin gland in
the head of some birds,
especially marine birds that
excrete excess salt
Mammalian Integument
Features:
1. Epidermis is differentiated into
distinct layers; chromatophores
prominent (secrete melanin)
2. Skin color results from a
combination of the yellow stratum
corneum, the red underlying blood
vessels, and the dark pigment
granules (melanin)
3. Dermis = 2 layers: outer papillary
layer pushes fingerlike projections
(dermal papillae) into the epidermis;
deeper reticular layer has fibrous
connective tissue; blood vessels,
nerves, and smooth muscle occupy
the dermis but do not reach the
epidermis
4. Dermal bones contribute to the skull
and pectoral girdle
5. Glands = sebaceous and sweat
glands (scent and mammary glands)
Who are the chordates?
Dorsal = Chordin
Ventral = BMP
Dorsal = BMP (Bone Morphogenetic Protein)
Ventral = Chordin
So, who are the vertebrates?
The Vertebrata include all
animals with a segmented
vertebral column, a head
skeleton, tripartite brain, and
ectodermal placodes. Notice that
all of these have something to do
with advances in locomotion
(ectodermal placodes develop
into special sensory organs such
as equilibrium, hearing,
taste/smell, vision which
facilitate moving forward to find
things and not bump into things.
The development of the brain
allows for increased processing
of this sensory input. The head
skeleton provides a protective
shell for the sensory organs).
cephalochordates
urochordates
hagfish
lamprey
gnathostomes
Who are the vertebrates?
But… “Where are the Defining Traits
of Vertebrates?”
http://www.emc.maricopa.edu/faculty/farabee/biobk/cladogram_1.gif
We Have to Consider the Life History of a Vertebrate…
Development of Vertebrates Proceeds from General to Specific:
Conservatism or Preservationism in Ontogeny
During early development, there is
considerable similarity among
vertebrate embryos followed by
increasing differentiation toward adult
stages; an interesting trend from
general to specific!
Stages of Early Development in Vertebrates
Gastrulation
BLASTOMERE = cell produced during cleavage
EARLY DEVELOPMENTAL STAGES:
1. MORULA = a solid mass of cells formed after
several cell division (cleavage)
2. BLASTULA = a spherical mass formed by
blastomeres moving toward the periphery of the
mass, organizing into a layer of cells surrounding a
fluid-filled cavity called the BLASTOCOEL
3. GASTRULA = marked by the formation of the
BLASTOPORE and ARCHENTERON (or
GASTROCOEL) during GASTRULATION
4. NEURULA = formation of the ECTODERMAL
TUBE, the NEURAL TUBE (CNS forerunner!) and the
enclosed cavity called the NEUROCOEL during
NEURULATION
Neurulation
Gastrulation and Neurulation
http://www.palaeos.com/Vertebrates/Lists/Glossary/Images/
Endoderm.gif
Gastrulation and Neurulation
Primary
Germ Layers:
How do cells move during differentiation???
cavity enclosed within the mesoderm
EPIBOLY = cells spread across the outer surface
as a unit
INVOLUTION = cells may turn inward and then
spread over the internal surface
INVAGINATION = cells form a wall and then
indent or fold inward
DELAMINATION = cells form sheets and split into
parallel layers
INGRESSION = individual surface cells migrate to
the interior of the embryo
Variation in the Process of Neurulation…
PRIMARY NEURULATION
SECONDARY NEURULATION
(tetrapods, sharks, lungfishes)
(lamprey and teleost fishes)
1. At the dorsal and along the anterior-posterior body axis,
the ectoderm thickens into a strip of tissue, NEURAL
1.
PLATE.
2.
The thickened neural plate sinks inward from
the surface along the dorsal midline, forming a
solid rod of ectodermal cells, the NEURAL
KEEL.
The NEUROCOEL appears via cavitation within
the previously solid neural keel.
2. The neural plate grows inward into parallel ridges, the NEURAL FOLDS.
3. The neural folds eventually meet and fuse at the midline, forming the NEURAL TUBE that encloses the NEUROCOEL.
How Do Neural Crest Cells Form???
As the the neural
plate folds during
primary neurulation,
some cells within the
ectodermal folds
separate out and
establish a distinct
population of
NEURAL CREST
cells.
https://people.creighton.edu/
~idc24708/Genes/Behavioral
%20Genetics/3step%20neurulation.png
REMEMBER: “The neural crest cells
and ectodermal placodes are embryonic
structures found solely in vertebrates
and nowhere else in the animal
kingdom, not even among the other
chordates outside the vertebrates.”
(Kardong et al. 2012)
Table 5.2
The Ectodermal Placodes
“Ectodermal Placodes
are anatomically
distinct from neural
crest cells, although
both may arise by
common
developmental
interactions. “ (Kardong
2012)
Examples:
1. The nasal and otic placodes in teleosts behave like the neural keel; they
form as solid buds, which then secondarily cavitate.
2. In other vertebrates, all placodes form as thickenings of the surface
ectoderm that sink inward to form specific sensory receptors.
Life History of a Vertebrate
Major reorganization of the embryo
at the end of neurulation:
1.Polarity based on animal-vegetal
pole is followed by bilateral
symmetry based on an anteriorposterior axis of the developing
embryonic body.
2.The 3 primary germ layers have
been delineated (ectoderm,
endoderm, and mesoderm).
3.The 3 germ layers become
strategically positioned next to
one another so that they can
mutually interact during
ORGANOGENESIS
Vertebrate Organogenesis
Histogenesis
4 primary categories of adult tissues: EPITHELIUM, CONNECTIVE TISSUE,
MUSCLE TISSUE, and NERVOUS TISSUE.
Histogenesis
The Coelom and its Compartments
Please answer all questions all questions have 2-3 parts so please focus and answers all questions.
1. Discuss the theory of EVOLUTION. Who are the leading scientists and
philosophers who influenced our views about the theory evolution? What are
their scientific and/or philosophical contributions that led to the formulation of the
concept of natural selection as a mechanism for the evolution of vertebrates?
2. Compare and contrast Homology and Analogy. Use examples (of characters or
traits) to support your discussion of these concepts. How does each of these
concepts advance your understanding of the evolution of vertebrates
3. Discuss the evolution of the vertebrates. In your discussion, include a critique of
each of the theories about the evolution of the vertebrates. What are the key
traits that are considered vertebrate innovations?
4. Identify two of your most favorite evolutionary biologists (e.g., Darwin, Owen) and
discuss how each impacted your understanding of the evolution of vertebrates.
Include an example of their pivotal work that has contributed to your
understanding of vertebrate evolution
Purchase answer to see full
attachment
http://www.emc.maricopa.edu/faculty/farabee/biobk/cladogram_1.gif
Where did Vertebrates come from?
://www.intechope
om/books/theygdala-a-discretetitaskingnager/amygdala-emotionalning-inebrates-amparativespective
How did they
get there?
Geologc Time
542MYA
A critical component to understanding
evolution, biodiversity, the structure and
biology of organisms, and ecological
interrelationships is:
TIME
It’s hard to grasp how much time has passed
since the earth was formed. A good analogy is
to make a movie of the entire history of the
earth. This movie will run for 30 days. You
can eat a lot of popcorn during the first 25
days, but don’t blink during the last few
minutes!
1
1 “day”
~ 150
MY
6
13
2
3
H A DE A N
4
5
E O N
First life?
7
8
Prokaryotic A
fossils
14
15
9
10
R C H E A N
16
17
11
12
E O N
18
19
PROTEROZOIC
20
27
21
22
Eukaryotic
fossils
23
28
30
29
24
EON
25
26
Multicellular
fossils
27
28
29
30
PALEOZOIC ERA
Aquatic
life and
invertebrates
dominate
Terrestrial
plants,
Aquatic
vertebrates,
amphibians
MESOZOIC
ERA
Coal
forests,
Insects
Birds,
flowering
plants
MESOZOIC
ERA
CENOZOIC
ERA
Reptiles
dominant,
mammals
Mammals
dominant,
humans: last
10 minutes
Event: Cambrian Explosion of Biodiversity
Age: ~ 540 mya
Time in Movie: Day 27
What is the Cambrian Explosion?
Variation Among Verterbrates
http://www.emc.maricopa.edu/faculty/farabee/biobk/cladogram_1.gif
Partitioning Phenotypic Variance
Phenotypic Variance (VP) = Genetic Effects (VE) +
Environmental Effects (VE) + V(GxE) + Verror
(Scheiner and Goodnight 1984; Via and Lande 1986)
Why are there different vertebrates?
http://www.whale.to/vaccine/wallace/1.html
Two young, British naturalists independently read Malthus’
essay in 1838
“Human population grew geometrically, at a rate faster than the rate of
increase in resource (food) availability, only the fittest (to compete for
the limited food supply) would survive.”
Charles Darwin (1809-1882)
http://www.calacademy.org
http://sandraoles.com
More Facts About
Darwin
▪Educated in Cambridge
▪ Naturalist on HMS Beagle in 1831
▪ collected, studied, stored
biological specimens
throughout South America
and South Pacific
▪ published “On the Origin of
Species by Natural
Selection” in 1859
HMS Beagle
Galapagos Islands
After the voyage
• Found that individuals struggled for existence
– Competition for:
• Food
• Space
• Predators
• shelter
Food
Shelter
Space
Finding mates
Predators
Descent with modification
• Every species – living or extinct – must
have descended by reproduction from
preexisting species
• That species in turn must be able to
change over time
Natural Selection
Plausible Processes Leading to
Descent with Modification
(Theory of Natural Selection)
• Overproduction
– More offspring produced than can survive
• Genetic Variation
– Within populations, individuals have different traits
• Struggle to survive
– Must compete for existence
• Differential reproduction
– Those with best adaptations are most likely to
survive and reproduce
Alfred.R. Wallace (1823-1913)
http://www.whale.to/vaccine/wallace/1.html
Evolution by natural selection (1858), independent of Darwin;
based on Malthus’ essay (1838)
“Human population grew geometrically, at a rate faster than the rate of
increase in resource (food) availability, only the fittest (to compete for
the limited food supply) would survive.”
Carl von Linne (1707-1778)
Linnaean classification:
Kingdom
Phylum
Class
Order
Family
Genus
species
http://www.encyclopedia.com
Binomial Nomenclature:
Carolus Linnaeus
Linnaean classification = this system groups organisms into ever smaller
and smaller groups (like a series of boxes within boxes, called a
nested hierarchy)
Animalia
(animals)
Plantae
(plants)
Fungi
(funguses)
Chordata
(vertebrates)
Mollusca
(snails, clams,
etc.)
Arthropoda
Coelenterata
(insects, spiders, (corals, jellyfish)
etc.)
Annelida
(segmented
worms)
Mammalia
(mammals)
Reptilia
(reptiles)
Aves
(birds)
Amphibia
(amphibians)
Agnatha etc.
(fish)
Primates
(primates)
Carnivora
(dogs, cats, and
seals)
Rodentia
(mice, rats,
squirrels, etc.)
Marsupialia
(opossums,
kangaroos, etc.)
Cetacea
Approximately 13
(whales, dolphins, others…
and porpoises)
Family
Hominidae
(humans and
apes)
Pongidae
(orangutans)
Hylobatidae
(gibbons)
Cebidae
(monkeys)
Lemuridae
(lemurs)
Genus
Homo
(humans)
Pan
(chimpanzees)
Gorilla
(gorillas)
Australopithecine
(extinct)
Species
sapiens
(100,000 BC)
neanderthalensis “archaic” sapiens erectus
(200,000 BC)
(400,000 BC)
(1.8 million BC)
Kingdom
Phylum
Class
Order
Protista
(protozoans)
Monera
(bacteria)
Approximately 16
others…
7 others…
habilis
(2.4 million BC)
http://members.cox.net/kdrum/Taxonomy.htm
Jean-Baptiste de Lamarck (1744-1829)
(National Museum of Natural History)
Evolution through
inheritance of
acquired
characteristics
http://picsdigger.com
http://rosshoneywill.com/2008/06/12/lamarcks-evolution
Lamarckian Evolution
http://vagitup.com/2011/06/15/arnies-kid/
http://www.popcrunch.com/68-celebrities-before-they-were-stars/
http://www.bodybuildbid.com/articles/mr
olympia/arnold-schwarzenegger.html
Richard Owen (1804-1892) – “Archetype” (biological blueprint)
http://www.taxidermy4cash.com/owen.html
His concept of the archetype
provided some explanation
for homologies.
Who are the Vertebrates?
Vertebrates belong to
the Phylum Chordata…
http://www.emc.maricopa.edu/faculty/farabee/biobk/cladogram_1.gif
What are Chordates?
The Chordate Body Plan
Endostyle or Thyroid?
Who are the chordates?
Dorsal = Chordin
Ventral = BMP
Dorsal = BMP (Bone Morphogenetic Protein)
Ventral = Chordin
Who are the Vertebrates?
Vertebrates belong to
the Phylum Chordata…
http://www.emc.maricopa.edu/faculty/farabee/biobk/cladogram_1.gif
EVOLUTION AS REMODELING
PREADAPTATION OR PROTOADAPTATION OR EXAPTATION
The form and function of a phenotype (i.e., structure, behavior, physiology) exists
before the biological role arises. Does change (evolution) in the trait
happen in anticipation of a biological role?
How similar are vertebrates?
Ancestry (Homology)
Function (Analogy)
Appearance (Homoplasy)
Homology
HOMOLOGOUS CHARACTERS = characters in different
organisms that are similar because they were inherited
from a common ancestor that also had that character.
Richard Owen (1804-1892) – “Archetype” (biological blueprint)
http://www.taxidermy4cash.com/owen.html
His concept of the archetype
provided some explanation
for homologies.
Analogy
ANALOGOUS CHARACTERS = characters that are
superficially similar because they evolved to serve the
same function, BUT, they have separate evolutionary
origins. Convergent Evolution.
Homoplasy
https://en.wikipedia.org/wiki/Diversity_of_fish
http://stevestonecoralreeffoundation.org/reefs/reefstoday7.html
Convergence of Design
(Analogy?)
Who are the Vertebrates?
Vertebrates belong to
the Phylum Chordata…
http://www.emc.maricopa.edu/faculty/farabee/biobk/cladogram_1.gif
What are Chordates?
The Chordate Body Plan
Endostyle or Thyroid?
The Animalia
SCHIZOCOELIC
ENTEROCOELIC
What are Chordates?
The Chordate Body Plan
Endostyle or Thyroid?
Who are the Vertebrates?
Vertebrates belong to
the Phylum Chordata…
http://www.emc.maricopa.edu/faculty/farabee/biobk/cladogram_1.gif
What are Chordates?
The Chordate Body Plan
Endostyle or Thyroid?
The Animalia
SCHIZOCOELIC
ENTEROCOELIC
What are Chordates?
The Chordate Body Plan
Endostyle or Thyroid?
The Notochord
Notochord = a slender rod
that develops from the
mesoderm in all chordates;
prevents collapse of the body,
and muscle contractions on
alternating sides efficiently
flex the body in swimming
strokes.
Dorsal Tubular Nerve Cord
Phylogenetic Relationships Within the “Protochordates”
Hemichordata, generalized acorn worm.
Hemichordates (hemi=half chordates) are marine worms with
apparent links to chordates and echinoderms.
Synapomorphy with chordates: pharyngeal slits.
Synapomorphy with echinoderms: tornaria larva of hemichordate
similar to dipleura larva of echinoderms; deuterostome embryology
Cephalochordata.
Branchiostoma lanceolatum
(amphioxus)
http://www.usm.maine.edu/bio/courses/bio2
05/amphioxus.jpg
The notochord extends to the rostral tip of the body, hence the name cephalochordate (head-notochord).
amphioxus
Body Size: ca 8 cm
Habitat: shallow sandy bottoms in
major oceans
Food Habits: filter diatoms and
other plankton via cilia to mouth
and pharynx and out through
atriopore; mucus is produced by
endostyle (functions in iodine
uptake; homologous to thyroid
gland)
Reproduction: males and females
swim up to the water column to
spawn in early summer
Life cycle: larvae planktonic for 2-5
months, then metamorphose; very
abundant (1000/m3); larvae and
juveniles undergo vertical
migrations; sexually mature in 2-3
years, benthic; adults live for 1-4
years.
Urochordata.
http://kentsimmons.uwinnipeg.ca/16cm05/1116/chordate.htm
http://www.oceanwideimages.com/images/7544/large/24M120509-strawberry-tunicate.jpg
Origin of the Chordates?
1. Chordate from Annelid and Arthropod Hypothesis
(Geoffroy Sint-Hillaire, 1822)
2. Chordates from Echinoderms Hypothesis
(Garstang’s Hypothesis)
Chordate from Annelid and Arthropod
Hypothesis; Geoffroy Sint-Hillaire, 1822)
http://image.tutorvista.com/content/animal-kingdom/phylum-annelida.jpeg
Chordate origins?
Molecular phylogeny of some animal clades, including the
vertebrates. Validity of the upside down arthropod /
annelid hypothesis ???
Chordates from Echinoderms Hypothesis. -Garstang’s Hypothesis.
http://www.bio.miami.edu/dana/pix/echinoderm_collage.jpg
Chordate origins?
Who are the chordates?
Dorsal = Chordin
Ventral = BMP
Dorsal = BMP (Bone Morphogenetic Protein)
Ventral = Chordin
So, who are the vertebrates?
The Vertebrata include all
animals with a segmented
vertebral column, a head
skeleton, tripartite brain, and
ectodermal placodes. Notice that
all of these have something to do
with advances in locomotion
(ectodermal placodes develop
into special sensory organs such
as equilibrium, hearing,
taste/smell, vision which
facilitate moving forward to find
things and not bump into things.
The development of the brain
allows for increased processing
of this sensory input. The head
skeleton provides a protective
shell for the sensory organs).
Innovations of the Vertebrates
(1) VERTEBRAL COLUMN
•http://www.nlm.nih.gov/MEDLINEPLUS/ency/imagepages/19469.htm
http://www.spineuniverse.com/displayarticle.php/article265.html
Innovations of the Vertebrates
(2) HEAD
http://www.human-anatomy.com/human-anatomy/sh202.htm
Innovations of the Vertebrates
(3) NEURAL CREST CELLS and EPIDERMAL
PLACODES: unique in vertebrates!
These special neural crest cells and placodes are the source of
adult structures that distinguish vertebrates from other
chordates!
cephalochordates
urochordates
hagfish
lamprey
gnathostomes
Who are the vertebrates?
Development of Vertebrates Proceeds from General to Specific:
Conservatism or Preservationism in Ontogeny
During early development, there is
considerable similarity among
vertebrate embryos followed by
increasing differentiation toward adult
stages; an interesting trend from
general to specific!
Some Functions of the Integument?
1.Resistance to mechanical injury
2.Barrier against pathogens
3.Maintains shape of an organism
4.Osmotic regulation
5.Gas and ion exchange
6.Thermoregulation
7.Holds sensory receptors
8.Holds feathers, hair, horns
9.Skin pigments
Early Development of the Vertebrate Integument
Gastrulatio
n
1. MORULA = a solid mass of cells formed
after several cell division (cleavage)
2. BLASTULA = a spherical mass formed by
blastomeres moving toward the periphery of
the mass, organizing into a layer of cells
surrounding a fluid-filled cavity called the
BLASTOCOEL
3. GASTRULA = marked by the formation of
the BLASTOPORE and ARCHENTERON (or
GASTROCOEL) during GASTRULATION
4. NEURULA = formation of the
ECTODERMAL TUBE, the NEURAL TUBE
(CNS forerunner!) and the enclosed cavity
called the NEUROCOEL during
NEURULATION
Neurulatio
n
Embryonic Development of the Skin (Neurulation)
1. Single-layered ectoderm produces
multilayered epidermis
2. Stratum basale (stratum
germinativum) rests upon the
basement membrane; replaces the
outer layer of cells called the
periderm
3. Dermis arises principally from the
dermatome
4. Stratum compactum = connective
tissue and ordered layer of collagen
fibers
5. Neural crest contribute to bony
armor and chromatophores
6. Nerves and blood vessels invade
the integument to round out its
structural composition
General Features of the Vertebrate Integument
Terrestrial Vertebrates: keratinized or cornified
layer (stratum corneum)
Keratinocytes → Keratinization → Keratin (protein)
hair, hooves, horn,
sheathes, callus or other
cornified structures
Specializations of the Vertebrate Integument
Skin Glands
Skin Derivatives in Vertebrates
Variation in Integument Functional Anatomy Among Vertebrates
Ostracoderms and Placoderms
(The First and Early Vertebrates)
Features:
1. Bony plates of dermal armor act as exoskeleton; Large, cranial
dermal bones form head shields; Dermal bones become smaller
posteriorly to form dermal scales.
2. Tubercles, made up of enamel and enamel-like substance over an
inner layer of dentin form the surface of these scales.
Hagfishes and Lampreys
Features:
1. Dermal bone is lost; scale-less skin.
2. Epidermis has lots of living epidermal cells, along
with unicellular glands (granular and club cells).
3. Dermis has layers of fibrous connective tissue and
pigment cells
4. Hagfish- skin has thread cells that release mucus and
multicellular slime glands that release slime to the
skin surface.
Chondrichthyes
Features:
1. Dermal bone is absent, but skin is covered with denticles (placoid
scales)
2. Secretory and epidermal cells are present in the epidermis
3. Dermis is made up of fibrous connective tissue, especially elastic
and collagen fibers
4. Placoid scale develops in the dermis but projects through the
epidermis
5. Chromatophores in lower epidermis and upper dermis
Osteichthyes (Bony Fishes)
Features:
1. Dermis = loose connective tissue
(upper layer) and dense fibrous
connective tissue (deeper layer)
2. Chromatophores found within the
dermis.
3. Scale is the most important
structural product of the dermis
4. Dermal scales do not pierce the
epidermis
5. Epidermis has basal and
epidermal layers of cells
(secretory and club cells). These
produce mucous cuticle, or
surface “slime.”
Types of Bony Fish Scales
Cosmoid scale (sarcopterygians)
= thick, layer of dentin (cosmine)
beneath a thin layer of enamel
resides upon two layers of bone
(vascular and lamellar)
Ganoid scale (primitive
acinopterygians, gars) = thick
surface coat of enamel (ganoin);
no dentin above dermal bone
Teleost scale is made of only
lamellar bone, acellular and
mostly noncalcified:
(1) Cycloid scale has concentric
rings, or circuli.
(2) Ctenoid scale has a fringe of
projections along its posterior
margin.
Amphibian Integument
Features:
1. Skin is involved in gas exchange
(Cutaneous Respiration) = capillary beds
in the lower epidermis and deeper dermis
2. Leydig cells in skin of larvae secrete
antibacterial and antivirus substances
3. Adults have no Leydig cells, but have
regionalized skin: strata basale,
spinosum, granulosum, and corneum
4. Two types of multicellular glands:
mucous (smaller) and poison glands
(granular glands; bigger) develop in the
dermis but empty into the surface via
ducts
Reptilian Integument
Features:
1. Keratinization more extensive and
less skin glands than amphibians
2. Epidermal scale (Scute) = fold in the
epidermis; no contribution from
dermis
3. Hinge = junction between scales
4. Gastralia = dermal bones in the
abdominal area
5. 3 regions of the epidermis: stratum
basale, stratum granulosum, and
stratum corneum
6. Molting / Ecdysis = removal of
extensive sections of superficial
epidermis: duplication of the deeper
layers of granulosum and corneum
occurs before this event
Integument in Birds
Features:
1. Feathers = nonvascular and
nonnervous products of
the epidermis and the
keratinizing system
2. Pterylae = distinctive tracts
of feathers
3. Uropygial Gland = skin
gland at the base of the tail
that secretes lipid and
protein products
4. Salt Gland = skin gland in
the head of some birds,
especially marine birds that
excrete excess salt
Mammalian Integument
Features:
1. Epidermis is differentiated into
distinct layers; chromatophores
prominent (secrete melanin)
2. Skin color results from a
combination of the yellow stratum
corneum, the red underlying blood
vessels, and the dark pigment
granules (melanin)
3. Dermis = 2 layers: outer papillary
layer pushes fingerlike projections
(dermal papillae) into the epidermis;
deeper reticular layer has fibrous
connective tissue; blood vessels,
nerves, and smooth muscle occupy
the dermis but do not reach the
epidermis
4. Dermal bones contribute to the skull
and pectoral girdle
5. Glands = sebaceous and sweat
glands (scent and mammary glands)
Who are the chordates?
Dorsal = Chordin
Ventral = BMP
Dorsal = BMP (Bone Morphogenetic Protein)
Ventral = Chordin
So, who are the vertebrates?
The Vertebrata include all
animals with a segmented
vertebral column, a head
skeleton, tripartite brain, and
ectodermal placodes. Notice that
all of these have something to do
with advances in locomotion
(ectodermal placodes develop
into special sensory organs such
as equilibrium, hearing,
taste/smell, vision which
facilitate moving forward to find
things and not bump into things.
The development of the brain
allows for increased processing
of this sensory input. The head
skeleton provides a protective
shell for the sensory organs).
cephalochordates
urochordates
hagfish
lamprey
gnathostomes
Who are the vertebrates?
But… “Where are the Defining Traits
of Vertebrates?”
http://www.emc.maricopa.edu/faculty/farabee/biobk/cladogram_1.gif
We Have to Consider the Life History of a Vertebrate…
Development of Vertebrates Proceeds from General to Specific:
Conservatism or Preservationism in Ontogeny
During early development, there is
considerable similarity among
vertebrate embryos followed by
increasing differentiation toward adult
stages; an interesting trend from
general to specific!
Stages of Early Development in Vertebrates
Gastrulation
BLASTOMERE = cell produced during cleavage
EARLY DEVELOPMENTAL STAGES:
1. MORULA = a solid mass of cells formed after
several cell division (cleavage)
2. BLASTULA = a spherical mass formed by
blastomeres moving toward the periphery of the
mass, organizing into a layer of cells surrounding a
fluid-filled cavity called the BLASTOCOEL
3. GASTRULA = marked by the formation of the
BLASTOPORE and ARCHENTERON (or
GASTROCOEL) during GASTRULATION
4. NEURULA = formation of the ECTODERMAL
TUBE, the NEURAL TUBE (CNS forerunner!) and the
enclosed cavity called the NEUROCOEL during
NEURULATION
Neurulation
Gastrulation and Neurulation
http://www.palaeos.com/Vertebrates/Lists/Glossary/Images/
Endoderm.gif
Gastrulation and Neurulation
Primary
Germ Layers:
How do cells move during differentiation???
cavity enclosed within the mesoderm
EPIBOLY = cells spread across the outer surface
as a unit
INVOLUTION = cells may turn inward and then
spread over the internal surface
INVAGINATION = cells form a wall and then
indent or fold inward
DELAMINATION = cells form sheets and split into
parallel layers
INGRESSION = individual surface cells migrate to
the interior of the embryo
Variation in the Process of Neurulation…
PRIMARY NEURULATION
SECONDARY NEURULATION
(tetrapods, sharks, lungfishes)
(lamprey and teleost fishes)
1. At the dorsal and along the anterior-posterior body axis,
the ectoderm thickens into a strip of tissue, NEURAL
1.
PLATE.
2.
The thickened neural plate sinks inward from
the surface along the dorsal midline, forming a
solid rod of ectodermal cells, the NEURAL
KEEL.
The NEUROCOEL appears via cavitation within
the previously solid neural keel.
2. The neural plate grows inward into parallel ridges, the NEURAL FOLDS.
3. The neural folds eventually meet and fuse at the midline, forming the NEURAL TUBE that encloses the NEUROCOEL.
How Do Neural Crest Cells Form???
As the the neural
plate folds during
primary neurulation,
some cells within the
ectodermal folds
separate out and
establish a distinct
population of
NEURAL CREST
cells.
https://people.creighton.edu/
~idc24708/Genes/Behavioral
%20Genetics/3step%20neurulation.png
REMEMBER: “The neural crest cells
and ectodermal placodes are embryonic
structures found solely in vertebrates
and nowhere else in the animal
kingdom, not even among the other
chordates outside the vertebrates.”
(Kardong et al. 2012)
Table 5.2
The Ectodermal Placodes
“Ectodermal Placodes
are anatomically
distinct from neural
crest cells, although
both may arise by
common
developmental
interactions. “ (Kardong
2012)
Examples:
1. The nasal and otic placodes in teleosts behave like the neural keel; they
form as solid buds, which then secondarily cavitate.
2. In other vertebrates, all placodes form as thickenings of the surface
ectoderm that sink inward to form specific sensory receptors.
Life History of a Vertebrate
Major reorganization of the embryo
at the end of neurulation:
1.Polarity based on animal-vegetal
pole is followed by bilateral
symmetry based on an anteriorposterior axis of the developing
embryonic body.
2.The 3 primary germ layers have
been delineated (ectoderm,
endoderm, and mesoderm).
3.The 3 germ layers become
strategically positioned next to
one another so that they can
mutually interact during
ORGANOGENESIS
Vertebrate Organogenesis
Histogenesis
4 primary categories of adult tissues: EPITHELIUM, CONNECTIVE TISSUE,
MUSCLE TISSUE, and NERVOUS TISSUE.
Histogenesis
The Coelom and its Compartments
Please answer all questions all questions have 2-3 parts so please focus and answers all questions.
1. Discuss the theory of EVOLUTION. Who are the leading scientists and
philosophers who influenced our views about the theory evolution? What are
their scientific and/or philosophical contributions that led to the formulation of the
concept of natural selection as a mechanism for the evolution of vertebrates?
2. Compare and contrast Homology and Analogy. Use examples (of characters or
traits) to support your discussion of these concepts. How does each of these
concepts advance your understanding of the evolution of vertebrates
3. Discuss the evolution of the vertebrates. In your discussion, include a critique of
each of the theories about the evolution of the vertebrates. What are the key
traits that are considered vertebrate innovations?
4. Identify two of your most favorite evolutionary biologists (e.g., Darwin, Owen) and
discuss how each impacted your understanding of the evolution of vertebrates.
Include an example of their pivotal work that has contributed to your
understanding of vertebrate evolution
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