Bio 123: PP15 Material Flashcards

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1
Q

What are the 4 key characteristics of Chordates?

A

1) There is a presence of notochord
2)The nerve cord runs parallel with the notochord and gut, anterior end develops into the brain
3)Gill slits penetrate the wall of a pharynx (at least at some point in embryological development)
4) Tail extends past the anus (at least at some point of their development)

*** All of these features are present is chordate embryos

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2
Q

Do all vertebrata have vertebrates?

A

NO

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3
Q

What are 2 basic characteristics of Chordates?

A

They are coelomate and demonstrate bilateral symmetry.

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4
Q

What is the Notochord?

A

It is a rod of stiffened, but flexible, tissue that helps support the body.

The notochord also later develops into the vertebral column

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5
Q

What are some characteristics of the bodily systems of chordates?

A

-They have a defined central nervous system
-The pharynx moves from a digestive tract to a respiratory organ

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6
Q

What are the 3 major sub-phyla of chordates?

A

1) Urochordata (invertebrates)
2) Cephalochordata (invertebrates)
3) Vetebrata

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7
Q

What is a distinguishing characteristics of the vetebrata?

A

The vertebral column evolves from primitive notochord, composed on individual vertebral bones and are separated by disks (ligaments)

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8
Q

What is the common name for Urochordata?

A

They are known as sea squirts or tunicates.

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9
Q

What are the characteristics of Urochordata?

A

-Is the most ancestral sub-phylum of chordates.
-They begin as bilateral larvae swimmers
-Adults display evolutionary reversals
-They have a jellylike tunic around the pharynx
-Most are a few centimeters long
-Live in a variety of aquatic habitats
-Are filter feeders and have an incurrent and outcurrent siphon, gill slits
-The pharynx is a respiratory organ as well
-Gas exchange is done through diffusion

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10
Q

What are some reversals that we see in adult Urochordates?

A

-Their tail is reabsorbed
-They take on more of a radial symmetry
-Their nerve cord is absorbed into their body
-They gather oxygen through diffusion
-Have a basic circulatory system

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11
Q

What is the tunicate?

A

The larva form of urochordates

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12
Q

What are the characteristics of Cephalochordata?

A

-Closets relatives to Vertebrata
-Only 3-7 cm long
-Body display all chordate features throughout their life
-Have a head and a simple brains with neurons
-Have segmented muscles
-Are filter feeders
-Nerve cord sits dorsal to the notocord
-Tail is used for balance

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13
Q

What are some major body characteristics of Cephalochordata?

A

-Have an eyespot
-Tentacle like structures around the mouth
-Dorsal tubular nerve cord
-Notocord
-Pharynx with gill slits
-tail extending past anus

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14
Q

What are the myomeres?

A

They are each segmented muslce

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15
Q

What are the characteristics of Vertebrata?

A

-Pharynx completely shifts to gas exchange
-Accessory digestive organs such as the liver and pancreas
-Have chambered hearts
-Have tripartite brain
-Have advanced sensory structures (increased cephalization)
-Have an affinity for oxygen in red blood cells (hemoglobin)
-Have kidneys
-Have an endocrine system

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16
Q

What does tripartite brain mean?

A

That the brain have a forebrain, midbrain, and hindbrain

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17
Q

What is the purpose of the liver in vertebrata?

A

It secretes bile and metabolizes protein, fats, and other substances

18
Q

What is the purpose of the pancreas?

A

It regulates sugar levels in the blood

19
Q

Define emulsification

A

The process in which large lipid globules are broken down into smaller lipid globules.

20
Q

What classes fall under the sub phylum Vertebrata?

A

Myxini (Hagfish)
Petromyzontida (lamprey)

21
Q

What is the ancestral state of hearts?

A

Having 2 chambers

22
Q

What is the derived state of hearts?

A

Having 4 chambers (Birds and mammals have 4 heart chambers)

23
Q

Excretory system

A

Is made of individual units known as nephrons that filter the blood and get rid of waste (bladder and kidneys included)

24
Q

What is a unique characteristics of Myxini?

A

They are the most ancestral class within the vertebrata and their new characteristic is that they have a cranium

25
Q

What is the earliest cranium made out of?

A

Cartilage

26
Q

What are the characteristics of Myxini?

A

-Known as hagfish
-Do not have a true vertebral column
-First group with a cranium
-Cartilage protects their brain (no bone yet)
-Less that a meter long
-Nearly blind
-Finds found through sensory tentacles
-Are relatively sessile and have low metabolic rates
-unique predatory defenses
-Closely related to lamprey and have jawless lineages

27
Q

Define the cranium

A

It is a hardened structure made out of cartilage that protects the brain.

28
Q

What is the defense mechanism of hagfish?

A

They excrete a thick slime into the environment that basically clogs the gills of its predators which causes them to suffocate and die.

29
Q

What is a new characteristic found in Petromyzontida?

A

Their new characteristic is that they have a true vertebral column

30
Q

What are the characteristics of Petromyzontida (lampreys)?

A
  • Become distinct due to the presence of a vertebrate (First true vertebrates)
    -Are jawless
    -Are parasitic
    -Have a small cerebellum
    -Have sensory structures such as eyes well, two-pairs of semicircular canals
    -Well established in great lakes
    -Defined CNS
31
Q

What is the purpose of the cerebellum?

A

Responsible for balance and equillibrium

32
Q

What are ammocoetes?

A

The larvae of petromyzontida (hagfish)

33
Q

What is the life cycle of hagfish?

A

-M/F hagfish seek out riffle areas and create a crescent shaped nests with gravel and small stones
-They place their fertilized eggs among the gravel which hatch a few weeks later
-Larvae emerge from the nests and drift downstream.
-These larvae will burrow into silt and will remain there for 3-5 years until they mature.
-adult parasites will leave silt as sea lampreys and feed on fish.

*** each adult lamprey will spend 12-18 months in the lakes and destroy up to 40 pound of fish.

34
Q

What are the ecological issues with hagfish?

A

Hagfish are a highly invasive species and they are causing a decline in the fish population in great lakes. It has commercial affects because fishing companies cannot take to market fish that have been bitten and there is a decrease in fish population.

35
Q

What are the teeth of hagfish made out of?

A

Keratin

36
Q

Explain the semicircular canals

A

Sensory structures that are the earliest development of ear canals

37
Q

Vertigo

A

Sensation of feeling dizzy

38
Q

Invasive species

A

Any species that moves into a havitat that is not native to them and they over compete against the native species

39
Q

What are some physical features of hagfish?

A

-Eye
-Nostril
-Buccal tunnel
-External gill slits
- Anterior dorsal fin
-Caudal fin
-Tail
-Cloacal aperture

40
Q

Lampricide

A

A pesticide used to try to control sea lamprey populations. This pesticide specifically targets the larval stage of the sea lamprey.