Chordates are a diverse group of animals characterized by features such as a notochord, dorsal nerve cord, and pharyngeal slits. This summary provides an in-depth exploration of the phylum Chordata, including its subphyla: Urochordata, Cephalochordata, and Vertebrata. It covers essential characteristics, developmental stages, and the evolutionary significance of chordates. Ideal for biology students and educators, this resource aids in understanding the foundational concepts of chordate biology and anatomy. Key topics include the structure and function of chordate features, classifications, and the ecological roles of various chordate species.

Key Points

  • Explains the four primary features of chordates: notochord, dorsal nerve cord, pharyngeal slits, and post-anal tail.
  • Covers the three subphyla of Chordata: Urochordata, Cephalochordata, and Vertebrata.
  • Details the evolutionary significance of chordates and their ecological roles.
  • Includes information on vertebrate development and the transition from notochord to vertebral column.
Yahaya Mary
50 pages
Language:English
Type:Study Guide
Biology
Yahaya Mary
50 pages
Language:English
Type:Study Guide
Biology
129
/ 50
BIO209 SUMMARY: CHORDATES
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MODULE ONE: UNIT 1
Animals known as chordates belong to the phylum Chordata
A group of animals called chordates belong to the animal phylum Chordata
The group of animals called chordates includes these
Cephalochordates
Hemichordates
Urochordates
NB: Cephalochordates and Urochordates are invertebrates
Hemichordates are vertebrates
Which of the subphylum of the phylum Chordata is considered as a separate
phylum?
Hemichordata
There are 3 subphyla in the phylum Chordata
The three chordate subphyla
Urochordata
Cephalochordata
Vertebrata (Hemichordata)
Chordates possess the following (four) features
Notochord or vertebra column
Dorsal nerve cord
Pharyngeal slits
Post-anal tail
Dorsal nerve cord is otherwise called spinal cord
A dorsal fairly rigid rod of vacuolated cells found in Chordates is called notochord
or vertebra column
Notochord is a stiff but flexible rod (made up of tightly packed vacuolated cells
held in position by a firm sheath)
Notochord is made up of vacuolated cells
Vertebrates are known as modern chordates
In vertebrates, the notochord is modified or replaced in the course of
development into a bony vertebral column known as the spine or backbone
In the aquatic species (chordates), the notochord or vertebral column helps the
animal to swim by flexing its tail
The fluid-filled tube of nerve tissue that runs the length of the animal, dorsal to
the notochord is called Dorsal nerve cord
Dorsal nerve cord is present in chordates throughout embryonic and adult life
In fish and other vertebrates, the nerve cord is represented by the spinal cord
In fishes, the main communications line of the nervous system is Dorsal nerve
cord
The pharyngeal gill slits are pairs of openings through the pharynx that serve as
water exit holes through which water, drawn through the pharynx, is passed out
Invertebrate chordates use pharyngeal gill to trap food particles in the water
where the animals live
In fishes, the pharyngeal gill develop into true gills for breathing
Which of these groups possess true gills for respiration?
Reptiles
Birds
Fish
Mammals (including humans)
In reptiles, birds, and mammals (including humans), the gill slits are vestiges (gone
or no longer functional), occurring only in the embryonic stage
The part of the animal that extends backward behind the anus is called Muscular
post-anal tail
Basic/primary features of chordates
Notochord
Dorsal nerve cord
Pharyngeal gill slits
Muscular post-anal tail
Blocks of muscle (metameric musculature)
Triploblastic coelomates
Bilateral symmetry
Ventral heart
Limbs
Endoskeleton
Digestive system
Reproduction
Excretion
Coelom means “body cavity”
The body structure chordates are made up of three germ layers of embryonic cells
Chordates have four of appendages in the form of legs, arms, wings or fins
Inner skeleton is also called Endoskeleton
The digestive system of chordates comprises of
Stomach
Intestine
Mouth (tongue and teeth)
Chordates organ of respiration are lungs and gills
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FAQs

what are the key features of BIO209 Summary: Chordates

The key features of BIO209 Summary: Chordates include essential characteristics that define chordates as a group.

  • Notochord: A flexible rod that provides support.
  • Dorsal nerve cord: A nerve cord located along the back, which develops into the spinal cord in vertebrates.
  • Pharyngeal gill slits: Openings that serve various functions, including respiration in aquatic species.
  • Post-anal tail: An extension of the body past the anus, aiding in movement.
  • Metameric musculature: Segmented muscle blocks that assist in locomotion.

what does BIO209 Summary: Chordates cover

BIO209 Summary: Chordates covers the classification and features of chordates, a diverse group of animals.

  • Subphyla: It discusses the three main subphyla: Urochordata, Cephalochordata, and Vertebrata.
  • Evolution: The summary explores the evolutionary significance of chordates and their common ancestry.
  • Physiology: Key physiological traits such as the circulatory system and reproductive methods are detailed.
  • Habitat: The document highlights the various habitats where chordates can be found, from marine to terrestrial environments.

how do chordates reproduce according to BIO209 Summary: Chordates

According to BIO209 Summary: Chordates, chordates primarily reproduce sexually.

  • External fertilization: Common in aquatic species such as fish and amphibians.
  • Internal fertilization: Seen in many reptiles, birds, and mammals.
  • Oviparous and viviparous: Some species lay eggs (oviparous), while others give birth to live young (viviparous).
  • Metamorphosis: Many amphibians undergo metamorphosis, transitioning from aquatic larvae to terrestrial adults.

what are the differences between Urochordata and Cephalochordata in BIO209 Summary: Chordates

BIO209 Summary: Chordates outlines key differences between Urochordata and Cephalochordata.

FeatureUrochordataCephalochordata
NotochordPresent only in larval stagePersistent throughout life
Body StructureCovered by a tunicFish-like appearance
Feeding MechanismFilter feeders using gill slitsFilter feeders using numerous gill slits
HabitatMarine environmentsMarine environments

what is the significance of the notochord in BIO209 Summary: Chordates

The notochord is a crucial feature in BIO209 Summary: Chordates, serving as a primary support structure.

  • Support: Provides structural support during development.
  • Development: In vertebrates, it is replaced by the vertebral column during growth.
  • Movement: Facilitates swimming in aquatic species by allowing flexibility.
  • Evolutionary importance: Represents a key evolutionary trait linking invertebrates to vertebrates.

how do pharyngeal gill slits function in chordates according to BIO209 Summary: Chordates

In BIO209 Summary: Chordates, pharyngeal gill slits serve important functions in various chordate species.

  • Respiration: In fish, they develop into true gills for breathing.
  • Feeding: In invertebrate chordates, they trap food particles during filter feeding.
  • Embryonic development: Present during embryonic stages in all chordates, indicating a shared ancestry.

what are the main classes of Vertebrata in BIO209 Summary: Chordates

BIO209 Summary: Chordates identifies several main classes within the subphylum Vertebrata.

  • Agnatha: Jawless fish, including lampreys and hagfish.
  • Chondrichthyes: Cartilaginous fish, such as sharks and rays.
  • Osteichthyes: Bony fish, including most familiar fish species.
  • Amphibia: Amphibians like frogs and salamanders.
  • Reptilia: Reptiles, including snakes and lizards.
  • Aves: Birds, characterized by feathers and beaks.
  • Mammalia: Mammals, known for mammary glands and hair.

what is the evolutionary significance of chordates in BIO209 Summary: Chordates

BIO209 Summary: Chordates highlights the evolutionary significance of this group in the animal kingdom.

  • Common ancestry: Chordates share a common ancestor with other animal phyla, indicating evolutionary links.
  • Adaptation: They demonstrate various adaptations that have allowed them to thrive in diverse environments.
  • Evolution of vertebrates: The transition from invertebrates to vertebrates marks a significant evolutionary milestone.
  • Ecological roles: Chordates play vital roles in ecosystems as predators, prey, and competitors.

how do chordates differ from other animal groups according to BIO209 Summary: Chordates

BIO209 Summary: Chordates outlines key differences between chordates and other animal groups.

  • Notochord: Unique to chordates, providing a distinct structural feature.
  • Dorsal nerve cord: Present in chordates, absent in many other animal groups.
  • Body symmetry: Chordates exhibit bilateral symmetry, unlike some radial organisms.
  • Developmental stages: Chordates have specific embryonic features not found in other groups.