Enter a player name to begin or load your saved progress.
Vertebrates are primarily characterized by the presence of a notochord throughout their adult life and a cranium.
Answer: False
Explanation: While vertebrates are characterized by a cranium, the notochord in most vertebrates is replaced by a vertebral column during development, rather than persisting throughout adult life.
A post-anal tail and pharyngeal gills are among the five unique characteristics that define the phylum Chordata, to which vertebrates belong.
Answer: True
Explanation: The phylum Chordata, which includes vertebrates, is defined by five unique characteristics, including a post-anal tail and pharyngeal gills.
Vertebrates are uniquely distinguished from other animals by having a large brain divided into at least two sections and a two-chambered heart.
Answer: False
Explanation: Vertebrates are distinguished by a large brain divided into *three or more* sections and a muscular heart with *multiple* chambers, not specifically two sections or two chambers.
The term 'vertebrate' originates from a Latin word meaning 'to swim', reflecting their common mode of locomotion.
Answer: False
Explanation: The term 'vertebrate' derives from the Latin word *vertere*, meaning 'to turn', not 'to swim', although many vertebrates do move by swimming.
Most vertebrates move by utilizing muscles along their back, with their primary skeletal support provided by the flexible spine.
Answer: True
Explanation: Vertebrates typically move by swimming, using muscles along their back, and their primary skeletal support is provided by the flexible spine or vertebral column.
Aquatic vertebrates typically perform gas exchange using lungs, which evolved from the swim bladder.
Answer: False
Explanation: Aquatic vertebrates primarily perform gas exchange using gills. Lungs, which evolved from the swim bladder, are characteristic adaptations for air breathing in tetrapods, not typical for aquatic respiration.
The vertebral column in vertebrates primarily serves to protect the brain, while the cranium protects the spinal cord.
Answer: False
Explanation: The vertebral column primarily protects the spinal cord, whereas the cranium is responsible for protecting the brain.
What are the two defining physical characteristics of vertebrates?
Answer: A vertebral column and a cranium
Explanation: Vertebrates are fundamentally characterized by the presence of a vertebral column, which protects the spinal cord, and a cranium, which protects the brain.
Which of the following is a unique characteristic of the phylum Chordata that vertebrates share?
Answer: An endostyle, often developing into a thyroid gland
Explanation: Among the unique characteristics defining the phylum Chordata, which vertebrates share, is the presence of an endostyle, a structure that often develops into a thyroid gland.
What specific feature distinguishes vertebrates from all other animals, including other chordates?
Answer: A vertebral column
Explanation: The presence of a vertebral column, composed of bone or cartilage, is the defining feature that distinguishes vertebrates from all other animals, including other chordates.
From what Latin word does 'vertebrate' ultimately derive, meaning 'to turn'?
Answer: *Vertere*
Explanation: The term 'vertebrate' ultimately derives from the Latin word *vertere*, which means 'to turn'.
How do vertebrates typically move, and what provides their primary skeletal support?
Answer: They swim using muscles along their back, supported by the spine.
Explanation: Vertebrates, being bilaterally symmetrical, typically move through swimming, powered by muscles along their back, with the flexible spine providing essential skeletal support.
What is the primary function of the vertebral column in vertebrates?
Answer: To surround and protect the spinal cord.
Explanation: The vertebral column in vertebrates serves as the primary skeletal support and is crucial for surrounding and protecting the spinal cord.
The earliest known vertebrates appeared approximately 445 million years ago during the Ordovician period.
Answer: False
Explanation: The earliest known vertebrates appeared approximately 518 million years ago during the Cambrian Stage 3, not the Ordovician period.
Cephalisation is an evolutionary process that led to the development of a distinct head containing concentrated sense organs and a brain, which was advantageous for encountering stimuli first.
Answer: True
Explanation: Cephalisation, the evolutionary concentration of sense organs and a brain in a distinct head, provided an advantage by allowing the organism to encounter and process stimuli at the leading edge of its movement.
The jaws of vertebrates evolved from the second pair of gill arches, which originally supported the gills.
Answer: False
Explanation: The jaws of vertebrates evolved from the *first* pair of gill arches, not the second, which originally served to support the gills.
Tetrapods adapted to terrestrial life by losing gills, developing lungs from the swim bladder, and transforming bony fins into walking legs.
Answer: True
Explanation: Tetrapods adapted to terrestrial environments by evolving lungs from the swim bladder, losing gills, and transforming their bony fins into walking legs, supported by shoulder and pelvic girdles.
Early Cambrian vertebrates like *Haikouichthys* possessed jaws, which were a key adaptation for their survival.
Answer: False
Explanation: Early Cambrian vertebrates such as *Haikouichthys* possessed the basic vertebrate body plan but notably lacked jaws.
The Devonian period is often referred to as the 'Age of Fishes' due to the prevalence of jawed vertebrates during this time.
Answer: True
Explanation: The Devonian period is indeed known as the 'Age of Fishes' because jawed vertebrates became prevalent and diversified significantly during this geological era.
Amniotes, characterized by membranes around their embryo, emerged during the Permian period, allowing them to reproduce on dry land.
Answer: False
Explanation: Amniotes, defined by their embryonic membranes enabling terrestrial reproduction, branched off from amphibious tetrapods during the *Carboniferous* period, not the Permian.
The Mesozoic era began with the largest mass extinction in Earth's history and concluded with the Cretaceous–Paleogene extinction, which extirpated most dinosaurs.
Answer: True
Explanation: The Mesozoic era commenced with Earth's largest mass extinction event and concluded with the Cretaceous–Paleogene extinction, which led to the extirpation of most dinosaurs and many other vertebrate groups.
The Cenozoic era is known as the 'Age of Mammals' primarily because placental mammals became dominant in the Southern Hemisphere.
Answer: False
Explanation: The Cenozoic era is known as the 'Age of Mammals' due to their overall dominance following Mesozoic extinctions, with placental mammals primarily in the Northern Hemisphere and marsupials in the Southern, not solely due to placental dominance in the Southern Hemisphere.
Jawed vertebrates first appeared in the late Devonian period, which is why it's called the 'Age of Fishes'.
Answer: False
Explanation: Jawed vertebrates may have first appeared in the late Ordovician period, becoming prevalent during the Devonian, which is indeed called the 'Age of Fishes' due to their diversification, but not their initial appearance.
When did vertebrates first appear on Earth?
Answer: Approximately 518 million years ago in the Cambrian Stage 3.
Explanation: The earliest known vertebrates originated during the Cambrian explosion, specifically in Cambrian Stage 3, approximately 518 million years ago.
What is cephalisation, and why was it an advantageous evolutionary trend in vertebrates?
Answer: The concentration of sense organs and a brain at the front of the body, advantageous for encountering stimuli first.
Explanation: Cephalisation is the evolutionary process of concentrating sense organs and a brain at the anterior end of the body, which is advantageous for an organism to detect and respond to environmental stimuli as it moves forward.
How did the jaws of vertebrates evolve?
Answer: From the first pair of gill arches.
Explanation: The jaws of vertebrates evolved from the first pair of gill arches, which originally served to support the gills.
What adaptation allowed tetrapods to breathe air on land, replacing the gills of their fish ancestors?
Answer: The adaptation of the swim bladder into lungs.
Explanation: Tetrapods adapted to terrestrial respiration by evolving lungs from the swim bladder, a structure used for buoyancy in their fish ancestors.
When and where did the earliest known vertebrates appear?
Answer: Cambrian explosion, approximately 518 million years ago, within the Chengjiang biota.
Explanation: The earliest known vertebrates emerged during the Cambrian explosion, around 518 million years ago, specifically within the Chengjiang biota.
Which geological period is often referred to as the 'Age of Fishes'?
Answer: Devonian
Explanation: The Devonian period is commonly referred to as the 'Age of Fishes' due to the significant diversification and prevalence of jawed vertebrates during this time.
How did lobe-finned fish adapt to terrestrial life, leading to the first amphibians?
Answer: They used their muscular paired fins, containing bones and joints, to propel themselves on land.
Explanation: Lobe-finned fish adapted to terrestrial life by utilizing their muscular paired fins, which contained bones and joints, for propulsion on land, eventually evolving into the walking legs of amphibians.
What is the defining characteristic of amniotes that allowed them to survive and reproduce on dry land?
Answer: Membranes around their embryo.
Explanation: Amniotes are defined by the presence of membranes around their embryo, a key adaptation that enabled them to reproduce successfully on dry land, independent of aquatic environments.
What significant event marked the beginning of the Mesozoic era for vertebrates?
Answer: The largest mass extinction in Earth's history.
Explanation: The Mesozoic era commenced with the largest mass extinction event in Earth's history, which profoundly impacted larger vertebrate groups.
Why is the Cenozoic era known as the 'Age of Mammals'?
Answer: Due to the dominance of mammals in terrestrial environments following the Mesozoic extinction events.
Explanation: The Cenozoic era is designated the 'Age of Mammals' because this group achieved ecological dominance in terrestrial environments after the extinction events of the Mesozoic era.
The subphylum Vertebrata is classified within the phylum Chordata and the clade Olfactores.
Answer: True
Explanation: The subphylum Vertebrata is indeed classified within the phylum Chordata and the clade Olfactores, as indicated by its scientific classification.
Elephants, sharks, and lampreys are all specific examples of animals included within the subphylum Vertebrata.
Answer: True
Explanation: The subphylum Vertebrata encompasses a wide range of animals, including mammals like elephants, cartilaginous fishes like sharks, and jawless fishes like lampreys.
Five molecular markers, known as conserved signature indels, exclusively distinguish all vertebrates from other animals.
Answer: True
Explanation: All vertebrates are exclusively distinguished from other animal groups by five specific molecular markers, identified as conserved signature indels in protein sequences.
The proteins Rrp44 and serine C-palmitoyltransferase are molecular markers that support a close relationship between vertebrates and cephalochordates.
Answer: False
Explanation: The proteins Rrp44 and serine C-palmitoyltransferase are molecular markers that exclusively support a close phylogenetic relationship between vertebrates and *tunicates*, not cephalochordates.
Jean-Baptiste Lamarck was the first to classify hagfishes as vertebrates in 1811.
Answer: False
Explanation: Carl Linnaeus initially classified hagfishes as Vermes in 1758, not as vertebrates. While Jean-Baptiste Lamarck defined vertebrates as a group in 1811, he did not specifically classify hagfishes as such.
The 'Cyclostomata hypothesis' proposes that modern jawless fishes, hagfishes and lampreys, form a monophyletic clade, supported by mtDNA sequencing analysis.
Answer: True
Explanation: The 'Cyclostomata hypothesis' posits that modern jawless fishes, specifically hagfishes and lampreys, constitute a monophyletic clade, a view strongly supported by mtDNA sequencing analysis.
Traditional evolutionary taxonomy groups extant vertebrates into nine classes, including two classes of extinct armored fishes.
Answer: False
Explanation: Traditional evolutionary taxonomy groups extant vertebrates into *seven* classes, with two additional classes for extinct armored fishes, not nine extant classes.
The group "Reptilia" is considered monophyletic when birds are excluded, as they share a common ancestor.
Answer: False
Explanation: The traditional group 'Reptilia' is considered paraphyletic when birds (Aves) are excluded, because birds evolved from reptiles and thus a monophyletic group must include all descendants of a common ancestor.
The 'Olfactores hypothesis' suggests that cephalochordates are the closest living relatives of vertebrates.
Answer: False
Explanation: The 'Olfactores hypothesis' proposes that tunicates, not cephalochordates, are the closest living relatives of vertebrates, forming a clade called Olfactores.
Fossil agnathans like Myllokunmingiida are placed within the Vertebrata crown group due to their fully developed vertebral column.
Answer: False
Explanation: Fossil agnathans like Myllokunmingiida are placed within the Vertebrata total group but *outside* the crown group, as they possessed only a rudimentary vertebral column, not a fully developed one.
To which larger phylum do vertebrates belong?
Answer: Chordata
Explanation: Vertebrates are classified as a subphylum within the larger phylum Chordata.
Which of the following is NOT listed as a major group of animals included within the subphylum Vertebrata?
Answer: Insects
Explanation: The subphylum Vertebrata includes mammals, birds, amphibians, and various classes of fish and reptiles, but not insects, which belong to the phylum Arthropoda.
Which of the following is one of the five molecular markers (conserved signature indels) that exclusively distinguish all vertebrates from other animals?
Answer: Protein synthesis elongation factor-2
Explanation: Protein synthesis elongation factor-2 is one of the five conserved signature indels in protein sequences that serve as exclusive molecular markers distinguishing all vertebrates from other animal groups.
What molecular evidence supports a close relationship between vertebrates and tunicates?
Answer: Exclusive sharing of proteins Rrp44 and serine C-palmitoyltransferase.
Explanation: The exclusive sharing of the proteins Rrp44 and serine C-palmitoyltransferase serves as molecular evidence supporting a close phylogenetic relationship between vertebrates and tunicates.
Who first defined vertebrates as a distinct taxonomic group in 1811?
Answer: Jean-Baptiste Lamarck
Explanation: Jean-Baptiste Lamarck is credited with first defining vertebrates as a distinct taxonomic group in 1811.
What was Carl Linnaeus's initial classification of hagfishes in 1758?
Answer: As Vermes.
Explanation: In 1758, Carl Linnaeus initially classified hagfishes within the group Vermes, not recognizing them as vertebrates.
What does the 'Cyclostomata hypothesis' propose regarding hagfishes and lampreys?
Answer: They form a monophyletic clade called Cyclostomata.
Explanation: The 'Cyclostomata hypothesis' posits that modern jawless fishes, specifically hagfishes and lampreys, form a monophyletic clade known as Cyclostomata.
Why are some traditional taxonomic groups, such as 'Reptilia' excluding 'Aves,' considered paraphyletic?
Answer: Because they do not include all descendants of a common ancestor.
Explanation: Traditional taxonomic groups like 'Reptilia' are considered paraphyletic when birds (Aves) are excluded because they fail to encompass all descendants of their common ancestor, which is a requirement for a monophyletic group.
What does the 'Olfactores hypothesis' suggest about the closest living relatives of vertebrates?
Answer: Tunicates are the closest living relatives.
Explanation: The 'Olfactores hypothesis' proposes that tunicates, forming a clade with vertebrates, are the closest living relatives of vertebrates, rather than cephalochordates.
How are fossil agnathans like Myllokunmingiida currently placed in the phylogeny of Vertebrata?
Answer: As part of the Vertebrata total group, but outside the Vertebrata crown group.
Explanation: Fossil agnathans such as Myllokunmingiida are currently placed within the Vertebrata total group, signifying their craniate status, but outside the Vertebrata crown group, as they possessed only a rudimentary vertebral column.
The smallest known vertebrate species is a type of fish, while the largest is a mammal.
Answer: False
Explanation: The smallest known vertebrate species is a frog (*Brachycephalus pulex*), not a fish, while the largest is indeed a mammal (blue whale).
According to the IUCN Red List 2014.3, the total estimated number of described extant vertebrate species is over 100,000.
Answer: False
Explanation: According to the IUCN Red List 2014.3, the total estimated number of described extant vertebrate species is 66,178, not over 100,000.
Tetrapods account for a slightly higher number of described extant species than non-phylogenetic 'fish'.
Answer: True
Explanation: Described extant vertebrate species are roughly evenly split between non-tetrapod 'fish' (over 32,900 species) and tetrapods (33,278 species), indicating tetrapods have a slightly higher number.
The estimated number of described extant species for lobe-finned fishes ("Sarcopterygii") is significantly higher than for amphibians.
Answer: False
Explanation: The estimated number of described extant species for lobe-finned fishes ('Sarcopterygii') is 8, which is significantly lower than for amphibians (7,302).
Vertebrates represent more than 5% of all described animal species.
Answer: False
Explanation: Vertebrates constitute less than 5% of all described animal species, with 66,178 described species compared to over 1.3 million described invertebrate species.
The Living Planet Index reported a 60% decline in vertebrate populations between 1970 and 2014.
Answer: True
Explanation: The Living Planet Index documented a substantial 60% decline in vertebrate populations globally between 1970 and 2014.
Freshwater vertebrate species have experienced an 83% decline since 1970, which is the most significant decline among specific populations mentioned.
Answer: True
Explanation: Among the specific populations listed, freshwater vertebrate species have experienced an 83% decline since 1970, as reported by the Living Planet Index.
Overexploitation of natural resources is one of the five main causes of biodiversity loss impacting vertebrate populations.
Answer: True
Explanation: Overexploitation of natural resources is indeed identified as one of the five primary causes contributing to biodiversity loss and the decline of vertebrate populations.
The blue whale, the largest vertebrate, can reach lengths of up to 108 feet and weigh around 150 tonnes.
Answer: True
Explanation: The blue whale, recognized as the largest vertebrate, can indeed attain lengths of up to 33 meters (108 feet) and weigh approximately 150 tonnes.
What is the approximate minimum adult snout-vent length of the smallest frog species, *Brachycephalus pulex*?
Answer: 6.45 millimeters
Explanation: The smallest known vertebrate, *Brachycephalus pulex*, has a minimum adult snout-vent length of approximately 6.45 millimeters.
According to the IUCN Red List 2014.3, what is the total estimated number of described extant vertebrate species?
Answer: 66,178
Explanation: The IUCN Red List 2014.3 reports the total estimated number of described extant vertebrate species as 66,178.
What is the approximate distribution of described extant species between 'fish' and tetrapods?
Answer: They are split roughly evenly, with tetrapods having slightly more.
Explanation: Described extant vertebrate species are approximately evenly distributed between non-tetrapod 'fish' (over 32,900 species) and tetrapods (33,278 species), with tetrapods accounting for a slightly higher number.
How many described extant species are estimated for Myxini (hagfish)?
Answer: 78
Explanation: The estimated number of described extant species for Myxini, commonly known as hagfish, is 78.
Which group of vertebrates has the highest estimated number of described extant species according to the provided data?
Answer: Actinopterygii (ray-finned bony fishes)
Explanation: According to the provided data, Actinopterygii (ray-finned bony fishes) have the highest estimated number of described extant species, with over 32,000.
What percentage of all described animal species do vertebrates constitute?
Answer: Less than 5%
Explanation: Vertebrates represent a relatively small fraction of global animal diversity, constituting less than 5% of all described animal species.
What trend did the Living Planet Index observe in vertebrate populations between 1970 and 2014?
Answer: A 60% decline in populations.
Explanation: The Living Planet Index reported a significant 60% decline in vertebrate populations globally over the period from 1970 to 2014.
Which specific vertebrate populations have seen the most significant decline since 1970, as reported by the Living Planet Index?
Answer: Freshwater vertebrate species.
Explanation: Among the specific populations listed, freshwater vertebrate species have experienced an 83% decline since 1970, as reported by the Living Planet Index.
Which of the following is NOT listed as one of the five main causes of biodiversity loss impacting vertebrate populations?
Answer: Volcanic activity
Explanation: The five main causes of biodiversity loss impacting vertebrate populations include land-use change, overexploitation, climate change, pollution, and invasive species; volcanic activity is not listed among them.
What is the estimated number of described extant species for Aves (birds)?
Answer: 10,425
Explanation: The estimated number of described extant species for Aves, commonly known as birds, is 10,425.
In all vertebrate embryos, the notochord persists into adulthood, providing primary skeletal support.
Answer: False
Explanation: In most vertebrate embryos, the notochord is replaced by a vertebral column during development, rather than persisting into adulthood as the primary skeletal support.
In adult tetrapods, pharyngeal arches primarily support the gills for aquatic respiration.
Answer: False
Explanation: In adult tetrapods, pharyngeal arches develop into structures such as parts of the jaw, ear, and larynx, while in adult fish, they support gills for aquatic respiration.
The hollow neural tube formed in vertebrate embryos subsequently develops into the spinal cord, with its front end differentiating to form the brain.
Answer: True
Explanation: The hollow neural tube, formed in vertebrate embryos, differentiates to become the spinal cord, with its anterior portion developing into the brain.
The endostyle, a unique feature of Chordata, often develops into a thyroid gland in vertebrates.
Answer: True
Explanation: The endostyle, one of the five unique characteristics of the phylum Chordata, frequently develops into the thyroid gland in vertebrates.
What is the fate of the notochord in most vertebrate embryos?
Answer: It is replaced by a vertebral column composed of bone or cartilage.
Explanation: In most vertebrate embryos, the notochord, a characteristic of chordates, is replaced by a vertebral column of bone or cartilage during development.
How do pharyngeal arches develop differently in adult fish versus adult tetrapods?
Answer: In fish, they support gills, while in tetrapods, they develop into parts of the jaw, ear, and larynx.
Explanation: Pharyngeal arches in adult fish support gills for aquatic respiration, whereas in adult tetrapods, they differentiate into structures such as parts of the jaw, ear, and larynx.
In the vertebrate embryo, what does the hollow neural tube primarily develop into?
Answer: The spinal cord and the brain.
Explanation: The hollow neural tube, a key structure in vertebrate embryonic development, differentiates to form the spinal cord and the brain.