Evolution of Animals II

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Questions and Answers

Which embryonic membrane is primarily responsible for gas exchange in amniotes?

Yolk sac

Allantois

Amnion

Chorion (correct)

What characteristic is unique to birds compared to other reptiles?

Dry skin with scales

Presence of feathers (correct)

Ectothermic metabolism

Multiple ovaries

Which factor contributes to the improved locomotion capacity observed in reptiles?

Behavioral temperature regulation

Development of a thoracic cage

Dry skin with scales (correct)

Presence of wings

What is the primary function of the allantois in amniotic embryos?

Facilitate metabolic waste disposal Signup and view all the answers

Which statement accurately describes the thermal regulation in reptiles?

Behavioral adaptations are used by ectothermic reptiles to control body temperature. Signup and view all the answers

What defines invertebrates in the context of animal evolution?

Absence of a backbone Signup and view all the answers

Which clade includes organisms characterized by the evolution of body symmetry?

Protosomia Signup and view all the answers

What role does the notochord play in vertebrate evolution?

It provides mechanical support and flexibility. Signup and view all the answers

Which of the following innovations is associated with the clade of vertebrates?

Formation of gill arches Signup and view all the answers

What adaptation is critical for tetrapods to successfully colonize land?

Adaptation of lungs for respiration Signup and view all the answers

Which characteristic is NOT typically associated with exaptations?

They are always beneficial for survival. Signup and view all the answers

How do gill arches and rods evolve in vertebrates?

They develop distinct features for land and water adaptations. Signup and view all the answers

What is the primary mode of reproduction in ovoviviparous species?

Embryo feeds on the yolk and hatches within the uterus. Signup and view all the answers

Which feature is characteristic of Osteichthyes but not present in Chondrichthyes?

Calcium phosphate bones. Signup and view all the answers

What is a distinguishing feature of Ray-finned bony fish (Actinopterygii)?

Their rays project from basal bones without an internal skeleton. Signup and view all the answers

Which of the following statements about lobed-finned bony fish (Sarcopterygii) is true?

They have a skeletal structure that allows for muscle attachment. Signup and view all the answers

What is homology in the context of vertebrate teeth?

Similarity due to shared ancestry. Signup and view all the answers

Which of the following is NOT a mode of reproduction in Chondrichthyes?

Ectopic. Signup and view all the answers

What adaptation allows early lobed-finned bony fish to interact with their environment?

The capacity to walk on substrate in wetlands. Signup and view all the answers

In what significant way do Osteichthyes differ from Cyclostomes?

Osteichthyes have a swim bladder, unlike Cyclostomes. Signup and view all the answers

Which characteristic is true for most bony fish (Osteichthyes)?

They are mainly oviparous. Signup and view all the answers

What adaptation allows Dipnoi (lungfish) to resist dry environments?

Burrowing in mud and going into torpor Signup and view all the answers

Which feature distinguishes tetrapods from their fish ancestors?

Development of a vascular system with lungs Signup and view all the answers

Which trait is NOT associated with the evolutionary transition of tetrapods from water to land?

Adaptation to hear in water Signup and view all the answers

Tiktaalik is significant in the study of tetrapod evolution because it exhibits traits from which two groups?

Fish and tetrapods Signup and view all the answers

Which of the following groups of amphibians includes species that are known for their elongated bodies and lack of limbs?

Apoda Signup and view all the answers

What environmental resources contributed to the evolution of tetrapods as they colonized land?

New sources of food, temperature variations, and reduced competition Signup and view all the answers

What is a defining characteristic of amphibian life cycles?

They undergo metamorphosis from aquatic to terrestrial forms. Signup and view all the answers

What primary evolutionary challenge did early tetrapods face when adapting to land?

Supporting their bodies against gravity Signup and view all the answers

Which of the following adaptations is NOT typically associated with tetrapods?

Utilization of lateral line systems Signup and view all the answers

Which factor was least influential in the initial colonization of land by vertebrates?

Evolving larger body sizes for competition Signup and view all the answers

What characteristic is shared by the phyla Porifera, Ctenophora, and Cnidaria?

Radial symmetry Signup and view all the answers

Which of the following statements accurately describes Ecdysozoa?

They undergo ecdysis to accommodate growth. Signup and view all the answers

What is the primary function of the notochord in Chordata?

To assist in locomotion by muscle attachment. Signup and view all the answers

Which organism would be classified under Lophotrochozoa?

Helix pomatia Signup and view all the answers

What feature distinguishes Bilateria from other animal groups?

Triploblastic structure with mesoderm Signup and view all the answers

What defines the embryological difference of Echinodermata compared to chordates?

Echinodermata do not have a notochord. Signup and view all the answers

What anatomical feature is associated with the feeding mechanism of Cephalochordates?

Pharyngeal slits Signup and view all the answers

What aspect of Cnidaria's structure contributes to their locomotion?

Medusa form with bell shape Signup and view all the answers

Which of the following is NOT true about the Acoela and Platyhelminthes?

They possess a digestive tract. Signup and view all the answers

Study Notes

Topic 13: The Evolution of Animals II

Learning Outcomes: Define key characteristics of invertebrates, classify invertebrate organisms, place the evolution of body symmetry on a phylogeny, justify the importance of the notochord in vertebrate evolution, organize key vertebrate innovations on a phylogeny, describe gill arch and rod evolution, explain early tetrapod adaptations for land colonization, classify tetrapod adaptations, and define exaptations.

Animal Phylogeny

Invertebrates: Make up 95% of known animal species. Invertebrate organisms are paraphyletic. They lack a backbone (spine).
Animal Phylogeny Diagram: Shows relationships among different animal groups, such as porifera, cnidaria, and bilateria. Also includes echinodermata. Shows evolutionary lineages and common ancestors.

Invertebrates

Porifera (Sponges): Diploblastic, radially symmetrical, sessile, lack true tissues.
Ctenophora (Comb Jellies): Diploblastic, radially symmetrical, have a nervous system.
Cnidaria (Jellyfish, Corals): Diploblastic, radially symmetrical, sessile polyps and swimming medusae, hydrostatic skeleton.
Bilateria: Bilateral symmetry, triploblasty (mesoderm), digestive tube develops from the blastopore, some have a coelom (body cavity). Includes acoela and platyhelminthes (lack a coelom and digestive tract), and lophotrochozoa (with lophophore or trochophore larval stage). Also includes ecdysozoa that periodically molt their exoskeleton (cuticle).
Lophotrochozoa: Some have a lophophore (crown of tentacles for feeding) or a trochophore larva. Examples include brachiopods and mollusks.
Echinodermata: Bilateral symmetry (larval stages), have a water vascular system for locomotion, feeding, respiration, and excretion.
Ecdysozoa: Protostomes with an exoskeleton.

Chordata (530 million years ago)

Key Characteristics: Notochord (longitudinal, flexible rod), dorsal hollow nerve chord, pharyngeal slits. post-anal tail.
Notochord: Key innovation that enabled muscle attachment for locomotion.

Vertebrates

Cyclostomes (Jawless Vertebrates): Lack jaws.
Gnathostomes (Jawed Vertebrates): Modification of gill arches creates jaws, increased complexity from two rods to multiple.

Chondrichthyes (Cartilaginous Fishes)

Characteristics: Cartilaginous skeleton, placoid scales, internal fertilization.

Osteichthyes (Bony Fishes)

Characteristics: Bony skeleton, swim bladder for buoyancy, internal skeleton to which muscles attach.

Dipnoi (Lungfish)

Characteristics: Functional lungs, adaptation for dry environments.

Tetrapods

Characteristics: Four limbs with digits, adaptations for land life, support against gravity, breathing in air, hearing in air.
Early Tetrapod Traits : Development of limbs with digits and ribs.
Amphibians: Aquatic larval stage with gills, metamorphosis to terrestrial form, loss of tail.
Amniotes: Amniotic egg protecting embryo from desiccation.

Reptiles

Characteristics: Dry skin with scales, ectothermic, improved locomotion. Evolved from amphibians.

Birds

Characteristics: Feathers as an adaptation for temperature regulation, courtship, protection, and later flight. Evolved from dinosaurs.

Mammals

Characteristics: Mammary glands, endothermy, larger forebrain, differentiated teeth, hair and fat layers. Evolved from reptiles.

Primates

Characteristics: Opposable thumbs for grasping, large brains, social behaviours.
Hominids: Bipedal locomotion, reduced jaws, short digestive tract. Language.

Humans

Characteristics: Bipedalism, reduced jaw bones, short digestive tract, complex language and symbolic thought, advanced tool use.

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Description

This quiz explores the evolution of invertebrates and key characteristics such as body symmetry and the notochord's significance in vertebrate evolution. It also covers phylogenetic relationships among various animal groups. Test your understanding of animal phylogeny and early adaptations of tetrapods for land colonization.

Evolution of Animals II - Invertebrates and Phylogeny

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