zoology

characteristics of vertebrates

• integument layers- epidermis and dermis

• distinctive cartilage or bone (endoskeleton w/vertebrae)

• cranium

• circulatory system consisting of ventral heart

• myomeres

“nothing in biology makes sense except in the light of evolutoin”

• believes change through time

Theodosius Dobzhansky

Concepts of animals changing through time dates back to

Anaximander

Darwin proposed what?

a model to explain the process of evolution

where did Darwin get the idea from?

from reverend thomas malthus who an essay about it

Malthus’ observation

• human population grows geometrically

• food supply doesn’t (it grows exponentially)

• more ppl are born than there is food for, not everyone is going to survive

Conclusions of Malthus - concluded by______

• Darwin!

  • concluded that only the fittest survive

fittest

ability to survived and reproduce

• success is determined by the number of offspring and the age

Non-amniotes vs amniotes

non amniotes lay their eggs in aquatic environments

-Non-amniotes lack the amnion, a feature of amniotes that protects the embryo from environmental fluctuations. Because of this, amniotes can reproduce on dry land by laying eggs or carrying fertilized eggs within the female.

animals that are amniotes

• synapsids (land animals)

  • mammals

• sauropsids (Reptilia)

  • aves

  • crocodilia

  • testudinia

non amniots

• hagfish

• lamprys

• chrondrichthyes

  • sharks, rays, ratfish

• osteichthyes (bony fish)

  • sarcopterygians

  • actinopterygians

phylogenetic tree

• biological classification reflect evolution

shows relationships of groups we are looking at over time

schools of classfication

numerical taxonomy (phenetics)

evolutionary taxonomy (ecletic system)

phylogenetic systematics (cladistics)

which classification do we use

phylogenetic systematics

who is the phylogenetic systematics developed by

willi henning

how does the PS classify organisms

based on derived characteristics, by evolutionary lineages

clade

evolutionary lineage or branches

apomorphy

new evolved trait

plesiomorphy

old

symplesiomorphy

shared old straight that evolved a long time ago

• aka apomorphy shared by different groups

parsimony

criteria used by scientists to determine the fewest steps in the phylogenetic tree

outgroup

a group of organisms not belonging to the group whose evolutionary relationships are being investigated.

ingroup

a group of organisms belonging to the group whose evolutionary relationships are being investigated.

polarity

- The states of characters used in a cladistic analysis, either original or derived.

parsimony

the principle that, out of all possible explanations for a phenomenon, the simplest of the set is most likely to be correct.

homolohgous traits are defined by

common underlying structure and position

Homoplasy

a rare evolutionary event that occurs when the same trait is independently acquired by unrelated organisms

convergence

separate evolution of similar structures in lineages that do not share common ancestry

• ex. endothermy in mammals and birds

• simple eye in octopus and vertebrae

taxon

naturally evolved group that has a name

ex. aves, primates, mammalia

monophyletic taxon

a group of organisms including a single common ancestor and all the decedents of that ancestor

paraphyletic taxon

a group that includes the common ancestor, and some descendants, but not all

polyphyletic taxon

a group that does not include the common ancestry or that includes descendant of more than one ancestry

gnathosomes

jawed vertebrates

agnatha

jawless fish

mobility difference in cephalochordates to vertebrates?

muscles changed from V shaped (primitive) to w shaped in vertabraes (derived)

the coloem is developed by the

mesoderm

the coelom is divided into to 2 to 3 sub cavities, what are they?

1. pleuroperitoneal

2. pericardial

3. pleural

(all 3 in mammals)

what is a deuterostome?

their anus forming before the mouth during embryonic development.

are vertebrae deuterostomes?

yes

what are the 3 germinal (triploblastic) layers in vertebrates

1. ectoderm (forms CNS)

2. mesoderm

3. endoderm

what does the mesoderm form

connective tissue, bones, circulatory system, muscles, urinary, and dermis

what does the endoderm form

part of the digestive system and the endocrine system

types of tissue

• epithelial

• connective (bone, cartilage, blood)

• nervous

• muscular

what does the notochord form?

it forms the vertebral column that attaches the axial muscles

axial muscles are composed of?

myomers

horizontal septum does what?

separates myomeres into epaxial (dorsal) and hypaxial (ventral) in jawed vertebrates

types of blood cells?

• red blood cells,

• white blood cells

• platelets/thrombocytes (for stoppage of bleeding) derived from megakarocytes

simple blood circulation/ simple cardiovascular system passage

• passes through the heart just one time

• blood-sinus venous-atrium-ventricle-conus arteriosum-gills (gas exchange) -body - Starts over again

In what animal does simple blood circulation occur?

in aquatic vertabraes

Double circulation passage

• passes through the hear 2x

• has 2 circuits: Pulmonary & Systematics

body- vena cava-right atrium-right ventricle- lungs- left atrium- left ventricle-aorta- body

what animals do double circulation happen?

terrestrial vertebrates

How many chambers does a heart with a simple circulation have?

Double circulation?

2

4

why is a fish heart more structurally simple than terrestrial vertebrates?

bc of gravity. fish are considered weightless. there were mustations bc of gravity and the weight that comes with it

excretory system

osmoregulation

a way to maintain body fluids concentration, is developed by the kidneys

why are kidneys different from agnatha to fishes and terrestrials vertebrates

terrestrial vertebrates would lose water and need to prevent it

nervous system includes what systems

central and peripheral systems

what are neurons on the PNS encased in….

the fatty coat, the myelin sheath

What is the PNS composed of

the somatic (voluntary) and visceral (involuntary)

Autonomic Nervous System (ANS) includes

sympathetic nervous system - pump much more blood

parasympathetic nervous system- slows down heart

CNS includes

brain and spinal cord

How does CNS develop? what is the process called?

it developed from an enlargment of the anterior portion of the nerve cord

called cephalization

Why is heat important

every chemical reaction needs a certain range of temperature in order for the body to work

• mainly due to enzymes

ectotherm

source of heat is external to the body

endothermy

source of energy is internal to the body

earliest vertebrates are the

ostracoderms and haikouichthys

hagfishes characteristics

• elongated body

• no dorsal fins

• many pharyngeal pouches> 16

• marine

• filter feeding behavior

• direct development, no larval stage

• diecious, some monoecious

lamprey characteristics

• elongated body

• anterior and posterior dorsal fins

• freshwater and marine

• separated sexes- dioescious

• parasites

• larval stage, ammocoete

• pharyngeal pouches

ostracoderms characteristics

• intermediate between jawless and jawed

• are jawless but are more derived than lampreys

what makes ostracoderms more derived than lampreys and hagfishes?

• dermal bone, aka carapace, a feature in jawed vertebraes

• moveable mouth plates, no jaws

• true pectoral plates but no jaws

• more developed eyes

what is more derived- gnathostomes or agnathans?

gnathostomes

what do developed jaws allow aquatic animals to do?

• have a variety of feeding behaviors, food optimization

• grasp objects to build nests, mates, and juveniles during parental care

• cut food with teeth

• explore other feeding behavior (ex. herbivory and carnivory)

• evolution of jaws was more efficient for gill ventilation rather than predation

• defense

what is the serial theory

first and second branchial arches gave rise to the mandibular arch. The third brachial arch gave rise to the hyoid arch and the rest of the branchial arches to the branchial arches of gnathostomes.

what is the composite theory

• 10 branchial arches were present in primitive species gave rise to the mandibular arch. All arches were used to make the mandibular arch

• the jaws origin was more complex involving the fusion and losses of branchial arches that came together and formed jaws

2 ways to obtain oxygen from water

• buccal pumping

• ram ventilation

• some can have both

what is buccal pumping

creates positive pressure by slowly opening and closing mouth

what is ram ventilation

some open their mouth permanently to gather water(sharks, swordfish)

gill anatomy includes

• gill arch

• primary lamellae

• afferent arteriole

• efferent arteriole

operculum what does it do and what is its purpose?

creates pressure so that the pressure inside the mouth is higher than the outside.

• forces gas to separate from the water

Countercurrent exchange

a mechanism that occurs when fluids flowing in opposite directions exchange heat or chemicals through a permeable barrier.

what are the air respiratory structures fishes use in water with low oxygen content?

• lungs

• enlarged lips

• vascularized chambers at the rear of the head

what did lungs appear/develop in fishes as

outpockets of the pharyngeal region of the digestive tract

what are the 2 possible locations of the lungs

• ventral surface of the gut (lungfishes tetra pods)

• dorsal surface of the gut (derived bony fishes)

do lungs require a large surface area?

yes

How do most fishes change buoyancy?

by holding air inside their body

• via lungs (teleost fishes) , swim bladder(teleost fishes) , or altering their air volume in their lungs (marine mammals)

how do teleost regulate swim bladder volume?

• secreting gas into the swim bladder when going down

• removing gas from swim bladder when going to surface

why do teleost regulate swim bladder volume?

to counteract external pressure

Swim bladder can be connected by the ____________ to the ______________

Swim bladder can be connected by the pneumatic duct aka physostomus to the intestines

what is it called when the swim bladder is not connected to the intestine?

physoclistous

how do Chondrichthyes’ preform buoyancy?

sharks do not have swim bladder but preform buoyancy by the liver

• liver makes up 25% body mass

what contribute to positive buoyancy in Chondrichthyes

• urea

• trimethylamine oxide

• chlorine ions

• nitrogenous compounds

what is the body internal environment determined by

ion concentration and temperature

what problem do freshwater fishes face to maintain their internal environment? marine water?

they have the tendance to gain water

• marine have the opposite problem

What organ maintains the internal body environment what do they regulate?

• kidney

  • they regulate ion concentrations

  • amounts of water

what is the process of maintaining the internal body environment called?

osmoregulation

Kidney functional and structural unit?

nephron

the nephron of the marine teleost is larger/smaller than the freshwater?

smaller

isosmolal fish

same salt concentration in the fish and the environment

hyposmolal fish

less salt in the fish than the environment