Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

General Biology: OrganismL Biology and Evolution - Set 1 > Vertebrates evolution > Flashcards

Vertebrates evolution Flashcards

1
Q

What are the roots of the Chordata phylum?

A

530 MYA
- Chordate-like fossils in Canada & China are ancestral “missing links” between invertebrates & vertebrates
- Similar to lancelets but appeared to have a
larger brain and eyes, no cranium
- Present but rare in Burgess Shale
- Segmented body & tentacles 1.5 inches long

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the four main features of chordates anatomy?

A
  • Notochord
  • Dorsal, hollow nerve cord
  • Pharyngeal slits
  • Muscular, post-anal tail
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a notochord?

A

The notochord is a longitudinal, flexible rod between the digestive tube and nerve cord
- It provides skeletal support throughout most of
the length of a chordate
- In most vertebrates, a more complex, joined
skeleton develops, and the adult retains only
remnants of the embryonic notochord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are dorsal hollow nerve cords?

A

The nerve cord of a chordate embryo develops from a plate of ectoderm that rolls into a tube dorsal to the notochord
- The nerve cord develops into the central
nervous system: the brain and the spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the muscular post-anal tail?

A

In many species, the tail is greatly reduced during embryonic development
- Chordates have a tail posterior to the anus
- The tail contains skeletal elements and muscle
blocks
- It provides propelling force in many aquatic
species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the pharyngeal clefts/slits?

A

In most chordates, grooves in the pharynx called pharyngeal clefts develop into slits that open to the outside of the body
- Functions of the pharyngeal slits:
- Suspension-feeding structures in many
invertebrate chordates
- Gas exchange in aquatic vertebrates
- Tetrapods have pharyngeal pouches that develop into parts of the ear, head, and neck (eustachian tube, middle ear, tonsils, parathyroid, and thymus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What do Hox genes control?

A

They control morphology

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How did Lewis discover hox genes?

A
  • Found a cluster of homeotic (Hox) genes in the
    chromosome
  • Saw colinearity in time and space
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What did the gene order in the cluster Lewis found mimic?

A

The order of expression of genes and their function along the anterior-posterior (A-P) body axis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does exhibiting temporal colinearity look like?

A

Having the anterior genes expressed first during development and posterior later

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are Hox genes?

A

Transcription factors
- Proteins that bind to specific sequences of DNA
(the Cis-regulatory elements) to control the
transcription of genetic information from DNA to
RNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do HOX genes orchestrate the construction of body parts?

A
  • DNA is wound up like a spool of yarn. As the
    spool is unwound the emerging genes become
    active
  • A new gene comes out of the spool every ninety
    minutes, which corresponds to the time needed
    for a new layer of the embryo to be built
  • It takes two days for the strand to completely
    unwind, the same time that’s needed for all the
    layers of the embryo to be completed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What organisms make up the subphylum Urochordata?

A

Also known as Tunicata, tunicates or sea squirts
- Two siphons
- Filter-feeding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are tunicates?

A

Adult animals without backbones, a Chordate-like larva

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does appearance of self-recognization affect?

A

Whether tissue transplants graft or are rejected
- Fusion/rejection based on sharing same allele
for FuHC gene (Fusion Histocompatibility
Complex)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What makes the vertebrates phylum special?

A
  • A skeletal system and complex nervous system
    that allows vertebrates efficiency at two essential
    tasks
    • Capturing food
    • Evading predators
  • Vertebrae enclosed the spinal chord and
    replaced notochord
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How many sets of Hox genes do vertebrates have?

A

2 sets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What do vertebrates possess that is involved in the formation of the cranium?

A

A neural crest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the neural crest and what does it form?

A
  • The neural crest is a group of embryonic cells
    that form near the dorsal margins of the closing
    neural tube
  • They form certain craniofacial structures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are craniates?

A

Chordates that have a head
- A distinct skull contains a brain at the anterior
end of the dorsal nerve cord, eyes and other
sensory organs
- Enables chordates to coordinate more complex
movement and feeding behaviors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the main differences between chordates and craniates?

A

Chordates
- One hox gene cluster
- Less active
- No muscles lining the digestive tract
- Tubular heart
- No kidneys

Craniates
- Two hox gene clusters
- More active + higher metabolic rate
- Muscular lining of digestive tract
- 2-chambered heart
- Kidneys
- Hemoglobin & Red blood cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What organism belongs to the myxini family?

A

Hagfish (~30 species)
- Marine scavengers
- Cartilaginous skeleton & notochord
- No jaws and very reduced vertebrae
- Fossil evidence date them at ~300 MYA
- Glands along body produce copious amounts of
slime

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What organism belongs to the Petromyzontida family?

A

Lampreys
- Represent the oldest living lineage of vertebrates
- Cartilaginous skeleton
- The notochord has cartilaginous projections that
enclose the nerve cord
- Jawless mouth
- External parasites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are conodonts?

A

Extinct jawless vertebrates with mineralized elements

25
What are ostracoderms?
Extinct jawless vertebrate with mineralized teeth and armor from ~450-375 MYA - Used muscular pharynx to suck in food
26
What hypothesis about mineralization was formed after the discovery of the ostracoderms?
Mineralization was initiated in teeth, then spread to armor, and later still to the endoskeleton
27
What are gnathostomes?
Vertebrates that have jaws and paired fins
28
What is the advantage of having jaws & paired fins?
Jaws & paired fins enabled many fish species to be active predators, allowing for diversification of lifestyles & nutrient sources
29
What is the current hypothesis about how vertebrates jaws evolved?
Vertebrate jaws evolved by modification of skeletal rods that previously supported anterior pharyngeal slits - Remaining gill slits remain as sites of respiration
30
What characteristic are common to gnathostomes?
- Genome duplication, including duplication of Hox genes - An enlarged forebrain associated with enhanced senses of smell and vision - The lateral line system, rows of organs sensitive to vibrations that are located along each side of the body of aquatic gnathostomes
31
What did the Silurian and early Devonian periods see a dramatic increase in?
Jawed fish in the fossil record
32
What kind of skeletal structure do cartilaginous fish have?
They have a flexible endoskeleton of cartilage rather than bone
33
What is the cartilaginous skeleton?
A derived condition
34
What is the evolution of the cartilaginous skeleton in chondrichthyes?
- Primitive gnathostomes that pre-date the Chondrichthyes had bony skeletons and teeth, ie. contained mineral mineral calcium phosphate - Bonelike tissues are found in some early shark fossils - Traces of bone found in scales, based of teeth, and on vertebrae surface - Loss of bone is modern Chondrichthyes emerged after they diverged from gnathostomes
35
What are osteichthyes (bony fish)
- The most numerous vertebrates, both in individuals & species (~30,000) - Bony endoskeleton containing calcium phosphate - Scales also derived from bone
36
What are the three extant classes?
- Actinopterygii: ray-finned fishes - Actinistia: lobe-finned fishes (coelocanths) - Dipnoi: lungfish
37
What kind of organisms belongs to the Actinopterygii class?
The ray-finned fishes - named for the bony rays that support fins - Includes bass, trout, perch, tuna and herring - Fins may be modified for maneuvering, defense, and other functions
38
What kind of organisms belongs to the Actinistia class?
Lobe-finned fishes with muscular pectoral & pelvic fins supported by extensions of bony skeleton
39
What did Marjorie Courtenay-Latimer do?
- Rediscovered Coelacanths, which were thought to have gone extinct 65 mya, in 1938 - Genus Latimeria is named for her - Now present in S. Africa and S. Pacific
40
What organism belongs to the dipnoi class?
Lungfish - Generally inhabit stagnant ponds & swamps - Can gulp air into lungs connected to the pharynx - Australian lungfish still have gills - During dry season, some lungfishes can burrow into mud & aestivate
41
Where would we find transitional species?
- Shallow estuary or tidal flat - Warm, equatorial climate - Late Devonian era, around 370 mya - Presently exposed for exploration
42
What did Ted Daeschler & Neil Shubin discover in 2006?
10 specimens of Tiktaalik found in a Canadian rock bed estimated to be 375 million years old
43
What fish like characteristics did the Tiktaalik specimens have?
- Gills and a lung, gills had a reduced bony covering - Had scales covering its body like a fish - Had fins that could be used for swimming
44
What tetrapod characteristics did the Tiktaalik specimens have?
-Had a flat skull - Had eyes on top of its skull - Had ear notches that were larger than those seen in other Devonian fish (notches later became ears) - Had a full set of ribs that were needed for breathing and support out of water - Had a neck that could move its head around
45
What was known about the fin skeleton that Tiktaalik specimen had?
- It is a transition between a fin and foot - Probably wasn't used for walking but could support animal's weight - Fossil record shows fins increasingly evolved an internal structure similar to limbed animals
46
What did Neil Subin dub the Tiktaalik and why?
He dubbed it a "FIshapod" because it possessed multiple intermediate characteristics of fish and tetrapods
47
Why was the date of the first tetrapod revised to 395 mya?
- Tracks were found on what would have been the Polish coast - Spacing indicates animals from 0.5 to 2.5 cm long - No fossil skeleton found yet
48
What are the five main characteristics of tetrapods?
- Four "feet" - Digits - feet have digits to transmit muscle force to ground - Neck - head is separated from body by 1 or more vertebrae - Pelvic girdle - bones fused to vertebrae so that force from hind legs on ground is transferred to rest of body - Pharyngeal clefts - give rise to facial structures and glands, loss of gills
49
What did amphibians benefit from as the earliest terrestrial tetrapods?
They benefited from moist climate, abundant food & relatively little competition
50
What amphibians live two lives?
Aquatic tadpole larva metamorphoses to a terrestrial adult frog - Tadpoles usually aquatic herbivores with gills, a lateral line system, and swim by undulating tail - During metamorphosis, the tadpole develops legs, the lateral line disappears, and gills are replaced by lungs - Adult frogs are carnivorous hunters
51
What amphibians live one life?
- Amphibians such as salamandres do not live 2 lives - larvae and adults look alike - Aquatic salamander species often show paedomorphosis - retention of larval features in a sexually mature adult
52
Where are amphibians generally found?
- Generally found near water or in very humid environments - Many species rely on moist skin for gas exchange - Eggs lack shell & dehydrate quickly in dry air
53
What kind of egg enables all-terrestrial life cycles?
An amniotic egg - Extraembryonic membranes function in gas exchange, waste storage, and transfer of stored nutrients to embryo
54
What reptilian adaptations for terrestrial life are not generally found in amphibians?
- Reptiles obtain oxygen with lungs (increasing use of ribcage), not through their skin - Scales, containing keratin, waterproof skin, preventing dehydration - Internal fertilization, has to occur before shell is secreted
55
What is an ectotherm?
- Organisms that regulate their body temperature through behavior adaptations like basking or panting - Most reptiles are ectothermic, absorbing external heat as the main source of body heat
56
What did scientists discover about dinosaurs when they were able to measure their body temperature?
That some dinosaurs were as warm as most modern mammals - They did this by measuring the concentrations of isotopes carbon-13 and oxygen-18 in bioapatite, a mineral found in teeth and bone
57
What did the sequences of T. rex collagen proteins indicate?
That the closest living relative to them is an ostrich
58
What are archaeopteryx?
Mesozoic birds known from Bavarian fossils, fist found in 1860 - Lived ~150 MYA, during late Jurassic - Had clawed forelimbs, teeth, and a long tail containing vertebrae - Probably glided or flew short distances
59
What were extinct by the end of the Cretaceous period?
Dinosaurs went extinct - Dinosaurs may have been in decline before the asteroid impact near Yucatan Peninsula

General Biology: OrganismL Biology and Evolution - Set 1 (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions