Animal Diversity I–III: Clades, Body Plans & Evolution

What are the shared derived characteristics of deuterostomes?

Radial, indeterminate cleavage

blastopore becomes the anus.

Name two phyla that belong to deuterostomes.

Echinodermata and Chordata.

What unique feature do echinoderms exhibit?

calcium carbonate endoskeleton

a water vascular system.

What are the derived traits of chordates?

Dorsal hollow nerve cord,

post-anal tail,

notochord,

pharyngeal gill slits.

What is the function of the dorsal hollow nerve cord in chordates?

It develops into the brain and spinal cord.

What does the notochord become in vertebrates?

It is replaced by the vertebral column.

What are pharyngeal slits used for in vertebrates?

They are used for respiration (gills) or essential head and neck structuring.

How does the post-anal tail vary among chordates?

It is present throughout life in some, only in larvae in others, and vestigial in humans.

What are the key traits of vertebrate clades?

Vertebrae column

What is a characteristic of basal vertebrates?

They are jawless fish with a cartilage skeleton.

What distinguishes gnathostomes?

They have a hinged jaw and a bony skeleton.

What are osteichthyes commonly known as?

Bony fish.

What adaptations do lobe-fins have?

Muscular fins/limbs for locomotion.

What is a defining characteristic of tetrapods?

They have four limbs with digits.

What is an amniote?

A vertebrate that has an amniotic egg and rib cage ventilation.

What are the key features of mammals?

Mammary glands and endothermy.

Give an example of a terrestrial mammal.

Humans, dogs, or cats.

What is the habitat of most amphibians?

Aquatic but also require moist terrestrial environments.

What is the significance of Hox clusters in vertebrates?

They contribute to increased genetic and developmental complexity.

What is the lifestyle of cephalochordata (lancelets)?

Free-swimming and filter-feeding.

What is a unique feature of urochordata (tunicates)?

They are majorly sessile as adults and filter-feed.

What type of skeleton do mammals have?

Bony skeleton.

What is the role of the swim bladder in osteichthyes?

It aids in buoyancy control.

What are the derived traits of mammals?

Mammary glands, give birth to live young (mostly), and endothermy (warm-blooded).

What are the three major groups of mammals?

Eutherians, Marsupials, and Monotremes.

What are the derived traits of primates?

Large brain, grasping hands/feet, forward-facing eyes, high parental care, complex social behavior, and fully opposable thumbs in monkeys and apes.

What is the closest living relative to humans?

Chimpanzees.

When did hominins diverge from the common ancestor with chimpanzees?

Approximately 7 million years ago.

What are Australopiths and when did they exist?

They are early hominins that existed approximately 4 million years ago and exhibited a fully upright posture.

What is the significance of the genus Homo?

It appeared approximately 2.4 million years ago and includes species like Homo neanderthalensis and Homo sapiens.

When did modern humans (Homo sapiens) originate?

Approximately 200,000-300,000 years ago in central Africa.

All terminal taxa for Metaoza Clade

1. chanoflagellates

2. Porifera

3. Cnidaria

4. Acoela

5. Echinodermata

6. Chordata

7. Platyhelminthes

8. Rotifera

9. mollusca

10. Annelida

11. Nematoda

12. Arthropoda

What are the 8 metazoa clades ?

1. Metazoa

2. Eumetazoa

3. Bilateria

4. Nephrozoa

5. Deutrostomia

6. Protostomia

7. Spirilla

8. Ecdysoza

What is a defining trait of Gnathostomata?

Hinged jaws for capturing prey and 4 Hox gene clusters.

What distinguishes Osteichthyes?

Bony endoskeleton made of calcium phosphate and lungs or swim bladders.

What are the derived traits of Lobe-fins (Sarcopterygii)?

Muscular, fleshy fins/limbs supported by internal rod-shaped bones.

What are the key features of Tetrapoda?

Four limbs with digits, a distinct neck, and a fused pelvic girdle for transferring locomotive forces on land.

What is the significance of the Amniota clade?

Presence of an amniotic egg and rib cage ventilation.

What are the derived traits of Mammalia?

Mammary glands, hair, subcutaneous fat layer for heat retention, and live birth in most species.

What are the key features of Echinodermata?

Pentamerous symmetry, calcium carbonate endoskeleton, and a unique water vascular system.

What characterizes Cephalochordata?

Basal invertebrate chordates that retain all four chordate traits into adulthood.

What defines Urochordata?

Basal invertebrate chordates that are marine suspension feeders with chordate traits prominent during the larval stage.

What are the characteristics of Jawless Fish?

Lack true hinged jaws and paired fins; retain a cartilaginous skeleton.

What defines Chondrichthyes?

Aquatic predators with hinged jaws and flexible cartilaginous skeletons.

What are the key features of Actinopterygii?

Aquatic vertebrates with a bony calcium-phosphate skeleton and fins supported by thin, flexible bony rays.

What distinguishes Actinistia?

Deep-sea aquatic lobe-fins with fleshy, muscular fins supported by internal rod-shaped bones.

What are the characteristics of Dipnoi?

Freshwater lobe-finned fish equipped with both functional lungs and gills.

What defines Amphibia?

Basal tetrapods with four limbs and thin, gas-permeable skin, tied to water for reproduction.

What are the key features of Reptilia?

Possess keratinized scutes or scales and lay shelled amniotic eggs on land.

What distinguishes Mammalia?

Endothermic vertebrates with hair, fat layers, and mammary glands, divided into Monotremes, Marsupials, and Eutherians.

What is heterotrophy?

An organism cannot produce its own food and relies on ingesting organic material for energy.

What is a characteristic of multicellular organisms?

An organization of many specialized cells that rely on one another for function.

What is the role of collagen in animals?

Collagen supports epithelial cells and is a major component of the extracellular matrix.

What are homeobox genes?

A group of regulatory genes that control the development of body plans in animals.

What is asymmetry in animal body plans?

No plane of symmetry through the body, resulting in no mirror images.

Define radial symmetry.

Any plane through the longitudinal axis produces approximate mirror images.

What is bilateral symmetry?

Only one plane of symmetry through the longitudinal axis, resulting in distinct left and right halves.

What are diploblasts?

Animals with two embryonic tissue layers: ectoderm and endoderm.

What are triploblasts?

Animals with three embryonic tissue layers: ectoderm, endoderm, and mesoderm.

What is a coelom?

A body cavity that is fluid-filled and located between the body wall and digestive tube.

What is a coelomate?

An organism with a true coelom completely lined with mesoderm tissue.

What defines a pseudocoelomate?

An organism with a coelom that is partially lined by mesoderm and partially by endoderm.

What is an acoelomate?

An organism that lacks a coelom.

Describe protostome development.

Involves spiral and determinate cleavage, with the blastopore developing into the mouth.

Describe deuterostome development.

Involves radial and indeterminate cleavage, with the blastopore developing into the anus.

What is the significance of the Cambrian Explosion?

It marks the first appearance of many body plans in the fossil record, occurring around 500-540 million years ago.

What are the derived traits of Eumetazoa?

Specialized tissues and symmetry.

What is the defining characteristic of Bilateria?

Bilateral symmetry and triploblasty.

What does Nephrozoa include?

Animals with coelom and excretory structures.

What are the phyla for spiralia?

1. Platyhelminthes

2. Rotifera

3. Mollusca

4. Annelida

What is the significance of the Spiralia clade?

It includes entirely invertebrate animals without a specific derived morphological trait.

Derived traits for Ecdysozoa ?

ecdysis, or molting of their outer covering.

What is the nutritional mode of animals?

Animals are chemoheterotrophs that ingest food and digest it internally.

What is the cellular structure of animals?

Eukaryotic and multicellular without cell walls, supported by an extracellular matrix.

What specialized tissues do most animals possess?

Muscle and nerve tissues for movement and impulse conduction.

What is the typical reproductive strategy of animals?

Sexual reproduction with a diploid-dominant life cycle.

What are the three major stages of embryonic development?

Cleavage, blastula formation, and gastrulation.

What are Homeobox / Hox genes responsible for?

Governing body patterning during development.

How is animal symmetry classified?

Into asymmetry, radial symmetry, and bilateral symmetry.

What is an example of an animal with asymmetry?

Sponges.

What type of symmetry do sea anemones exhibit?

Radial symmetry.

What is bilateral symmetry associated with?

Cephalization (head development) and directional movement.

What are the two major developmental pathways in bilaterians?

Protostome development and deuterostome development.

What type of cleavage occurs in protostome development?

Spiral and determinate cleavage.

What is the fate of the blastopore in protostome development?

The blastopore becomes the mouth.

What type of cleavage occurs in deuterostome development?

Radial and indeterminate cleavage.

What is the fate of the blastopore in deuterostome development?

The blastopore becomes the anus.

What are choanoflagellates?

The closest living unicellular relatives to animals.

What significant event occurred around 500-540 million years ago?

The Cambrian Explosion, marked by rapid evolution and appearance of major animal body plans.

What is Metazoa?

A monophyletic group encompassing all animals.

What are the derived traits of Eumztaeoa?

• specialized tissue

• Symmetry

What are the derived traits of Bilateria?

Bilateral symmetry and triploblasty.

What are the derived traits of Nephrozoa?

Coelom

What are the two clades of Protostomia?

Spiralia and Ecdysozoa.

What are the derived traits of Spiralia?

None, they are grouped by molecular evidence and protostome development.

What is ecdysis?

The process of molting and shedding of an external cuticle or exoskeleton.

What are the derived traits of Echinodermata?

Water vascular system, calcium carbonate endoskeleton, and adult pentamerous symmetry.

What are the shared derived traits of Chordata?

Notochord, dorsal hollow nerve cord, pharyngeal slits, and post-anal tail.

What defines vertebrates?

Cartilaginous or bony vertebrae replacing the notochord.

What are the derived traits of Gnathostomata?

Hinged jaws for prey capture and four Hox gene clusters.