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Questions and Answers
In organisms with a closed circulatory system, what is the direct route of blood circulation following its exit from the heart?
In organisms with a closed circulatory system, what is the direct route of blood circulation following its exit from the heart?
- Through a series of vessels with varying diameters. (correct)
- Entering the coelom for nutrient exchange.
- Directly bathing the cells and tissues.
- Filtering through the kidneys before reaching tissues.
How does the absence of mesoderm in diploblastic organisms affect their physiological complexity compared to triploblastic organisms?
How does the absence of mesoderm in diploblastic organisms affect their physiological complexity compared to triploblastic organisms?
- It restricts them to tissue-level organization and limits the development of true organs. (correct)
- It allows for more complex organ systems to develop.
- It enables them to develop a pseudocoelom.
- It has no impact on their physiological capabilities.
Which body plan is associated with the evolutionary advantage of cephalization and enhanced mobility?
Which body plan is associated with the evolutionary advantage of cephalization and enhanced mobility?
- Spherical symmetry
- Radial symmetry
- Bilateral symmetry (correct)
- Asymmetry
What is the most accurate interpretation of metamerism's significance in the evolutionary advancement of animal body plans?
What is the most accurate interpretation of metamerism's significance in the evolutionary advancement of animal body plans?
Which evolutionary advantage do coelomates possess compared to pseudocoelomates or acoelomates?
Which evolutionary advantage do coelomates possess compared to pseudocoelomates or acoelomates?
What is the developmental significance of the notochord in chordates?
What is the developmental significance of the notochord in chordates?
Examine the roles of choanocytes and porocytes. How do these cells coordinate to facilitate efficient water flow and filter feeding in sponges?
Examine the roles of choanocytes and porocytes. How do these cells coordinate to facilitate efficient water flow and filter feeding in sponges?
How does metagenesis in cnidarians contribute to their survival and adaptation in varying environmental conditions?
How does metagenesis in cnidarians contribute to their survival and adaptation in varying environmental conditions?
What specific functional advantage do flame cells provide to platyhelminthes in their osmoregulation and excretion processes?
What specific functional advantage do flame cells provide to platyhelminthes in their osmoregulation and excretion processes?
The presence of parapodia in Nereis directly facilitates which primary function in its aquatic lifestyle?
The presence of parapodia in Nereis directly facilitates which primary function in its aquatic lifestyle?
How do malpighian tubules contribute to the success and diversification of arthropods in terrestrial environments?
How do malpighian tubules contribute to the success and diversification of arthropods in terrestrial environments?
What adaptive advantage does the radula provide to molluscs in their diverse feeding strategies?
What adaptive advantage does the radula provide to molluscs in their diverse feeding strategies?
In the context of echinoderms, how does the water vascular system facilitate both locomotion and nutrient acquisition?
In the context of echinoderms, how does the water vascular system facilitate both locomotion and nutrient acquisition?
How does the presence of a stomochord in hemichordates provide insights into the evolutionary origins of chordates?
How does the presence of a stomochord in hemichordates provide insights into the evolutionary origins of chordates?
What fundamental distinction differentiates Urochordata from Cephalochordata, particularly concerning the notochord's extent and persistence?
What fundamental distinction differentiates Urochordata from Cephalochordata, particularly concerning the notochord's extent and persistence?
Examine adaptations within cyclostomes with focus on how they parasitize other fish, what feature is most crucial for their ectoparasitic lifestyle?
Examine adaptations within cyclostomes with focus on how they parasitize other fish, what feature is most crucial for their ectoparasitic lifestyle?
If an aquatic animal lacks an operculum, how would this affect its respiration and overall energy expenditure?
If an aquatic animal lacks an operculum, how would this affect its respiration and overall energy expenditure?
How do the unique adaptations in avian respiratory and skeletal systems contribute to their efficient flight?
How do the unique adaptations in avian respiratory and skeletal systems contribute to their efficient flight?
What is the significance of mammary glands in mammals, and how does this adaptation contribute to offspring survival and development?
What is the significance of mammary glands in mammals, and how does this adaptation contribute to offspring survival and development?
Given a terrestrial vertebrate exhibiting scutes, limited parental care, and internal fertilization, which class is most likely exhibiting those characteristics?
Given a terrestrial vertebrate exhibiting scutes, limited parental care, and internal fertilization, which class is most likely exhibiting those characteristics?
Flashcards
Cellular Level Organization
Cellular Level Organization
Cells arranged as loose aggregates with some division of labor.
Tissue Level Organization
Tissue Level Organization
Cells performing similar functions organized into distinct tissues.
Organ Level Organization
Organ Level Organization
Tissues grouped to form organs specialized for specific functions.
Organ System Level Organization
Organ System Level Organization
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Open Circulatory System
Open Circulatory System
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Closed Circulatory System
Closed Circulatory System
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Asymmetrical
Asymmetrical
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Radial Symmetry
Radial Symmetry
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Bilateral Symmetry
Bilateral Symmetry
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Diploblastic Organization
Diploblastic Organization
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Coelomates
Coelomates
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Pseudocoelomates
Pseudocoelomates
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Acoelomates
Acoelomates
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Segmentation (Metamerism)
Segmentation (Metamerism)
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Notochord
Notochord
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Chordates
Chordates
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Non-chordates
Non-chordates
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Water Transport System in Sponges
Water Transport System in Sponges
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Cnidoblasts (Cnidocytes)
Cnidoblasts (Cnidocytes)
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Polyp
Polyp
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Study Notes
Animal Kingdom Overview
- The need for animal classification arises due to the million+ identified species
- Classification is important for assigning newly discovered species
Basis of Classification
- Despite structural differences, animals share fundamental features
- These include cell arrangement, body symmetry, coelom nature, and digestive, circulatory, and reproductive patterns
Levels of Organisation
- Animalia kingdom members are multicellular
- Cellular level: cells arranged as loose aggregates with division of labor (e.g., sponges)
- Tissue level: cells performing similar functions organized into tissues (e.g., coelenterates)
- Organ level: tissues grouped into organs specialized for specific functions (e.g., Platyhelminthes)
- Organ system level: organs form functional systems with specific physiological functions (e.g., Echinoderms and Chordates)
- Digestive system complexity varies
- Platyhelminthes: incomplete system with a single opening
- Complete digestive system: two openings (mouth and anus)
- Circulatory systems exist in two primary forms
- Open type: blood pumped out of heart, directly bathing cells and tissues
- Closed type: blood circulates through vessels of varying diameters
Symmetry
- Animals can be categorized based on symmetry
- Asymmetrical: No plane can divide into equal halves (e.g., sponges)
- Radial symmetry: organism divided into identical halves by any plane passing through the central axis (e.g., coelenterates, ctenophores, echinoderms)
- Bilateral symmetry: body divided into identical left and right halves in only one plane (e.g., annelids, arthropods)
Diploblastic and Triploblastic Organization
- Diploblastic: Cells arranged in two embryonic layers (ectoderm and endoderm), with mesoglea in between (e.g., coelenterates)
- Triploblastic: Developing embryo possesses a third germinal layer (mesoderm) between the ectoderm and endoderm (Platyhelminthes to chordates)
Coelom
- Coelom presence or absence helps in classification
- Coelomates: Animals possessing a coelom lined by mesoderm (e.g., annelids, molluscs, arthropods, echinoderms, hemichordates, chordates)
- Pseudocoelomates: Body cavity not fully lined by mesoderm; mesoderm present as scattered pouches (e.g., aschelminthes)
- Acoelomates: Animals lacking a body cavity (e.g., platyhelminthes)
Segmentation
- Metameric segmentation: Body divided into segments with serial repetition of organs (e.g., earthworm)
Notochord
- Notochord: Mesodermally derived rod-like structure formed on the dorsal side during embryonic development in some animals
- Chordates: Animals possessing a notochord
- Non-chordates: Animals not possessing a notochord (e.g., porifera to echinoderms)
Classification of Animals - Broad Classification of Kingdom Animalia
- Porifera (sponges)
- Marine, mostly asymmetrical animals with a cellular level of organization
- Water transport or canal system (water enters through ostia into spongocoel, exits through osculum)
- Choanocytes/collar cells line spongocoel and canals
- Intracellular digestion
- Skeleton composed of spicules or spongin fibers
- Hermaphrodite
- Asexual (fragmentation) and sexual (gametes) reproduction
- Internal fertilization, indirect development with a larval stage
- Examples: Sycon (Scypha), Spongilla (freshwater sponge), Euspongia (bath sponge)
- Coelenterata (Cnidaria)
- Aquatic, mostly marine, sessile or free-swimming, radially symmetrical animals
- Cnidaria name derived from cnidoblasts/cnidocytes containing nematocysts
- Cnidoblasts are used for anchorage, defense, and prey capture
- Tissue-level organization and diploblastic
- Gastrovascular cavity with single opening (mouth on hypostome)
- Extracellular and intracellular digestion
- Some have calcium carbonate skeletons (corals)
- Two basic body forms: polyp (sessile, cylindrical) and medusa (umbrella-shaped, free-swimming)
- Exhibit metagenesis: polyps produce medusae asexually, medusae form polyps sexually (e.g., Obelia)
- Examples: Physalia (Portuguese man-of-war), Adamsia (sea anemone), Pennatula (sea-pen), Gorgonia (sea-fan), Meandrina (brain coral)
- Ctenophora
- Exclusively marine, radially symmetrical, diploblastic organisms with tissue-level organization
- Eight external rows of ciliated comb plates for locomotion
- Both extracellular and intracellular digestion
- Bioluminescence is well-marked
- Sexes are not separate
- Sexual reproduction only
- External fertilization with indirect development
- Examples: Pleurobrachia and Ctenoplana
- Platyhelminthes
- Dorso-ventrally flattened body (flatworms)
- Mostly endoparasites
- Bilaterally symmetrical, triploblastic, acoelomate with organ-level organization
- Hooks and suckers are used for parasitism
- Some absorb nutrients through their body surface
- Flame cells aid osmoregulation and excretion
- Sexes are not separate
- Internal fertilization
- Development proceeds through many larval stages
- Some members, such as Planaria, have high regeneration capacity.
- Examples: Taenia (tapeworm), Fasciola (liver fluke)
- Aschelminthes
- Body is circular in cross-section (roundworms)
- Free-living, aquatic, terrestrial, or parasitic in plants/animals
- Organ-system level of organization
- Bilaterally symmetrical, triploblastic, and pseudocoelomate
- Complete alimentary canal with muscular pharynx
- Excretory tube removes body wastes
- Sexes are separate (dioecious)
- Internal fertilization
- Development may be direct or indirect
- Examples: Ascaris (roundworm), Wuchereria (filaria worm), Ancylostoma (hookworm)
- Annelida
- Aquatic or terrestrial; free-living or parasitic
- Organ-system level of organization and bilateral symmetry
- Triploblastic, metamerically segmented and coelomate
- Body surface marked into segments/metameres
- Longitudinal and circular muscles aid locomotion
- Aquatic annelids (Nereis) have parapodia for swimming
- Closed circulatory system
- Nephridia aid osmoregulation and excretion
- Neural system consists of paired ganglia connected by nerves
- Nereis is dioecious, but earthworms and leeches are monoecious
- Sexual reproduction
- Examples: Nereis, Pheretima (earthworm), Hirudinaria (blood-sucking leech)
- Arthropoda
- Largest animal phylum, including insects
- Organ-system level of organization
- Bilaterally symmetrical, triploblastic, segmented, and coelomate
- Body covered by a chitinous exoskeleton; consists of head, thorax, and abdomen
- Jointed appendages
- Respiratory organs: gills, book gills, book lungs, or tracheal system
- Open circulatory system
- Sensory organs: antennae, eyes, statocysts
- Excretion via malpighian tubules
- Mostly dioecious
- Fertilization usually internal
- Mostly oviparous
- Development may be direct or indirect
- Examples: Apis (honey bee), Bombyx (silkworm), Laccifer (lac insect). Vectors: Anopheles, Culex, Aedes. Gregarious pest: Locusta, Living fossil: Limulus
- Mollusca
- Terrestrial or aquatic and has an organ-system level organisation
- Bilaterally symmetrical, triploblastic, coelomate animals
- Body covered by a calcareous shell and is unsegmented
- Distinct head, muscular foot, and visceral hump
- Mantle covers the visceral hump; mantle cavity contains feather-like gills
- Respiratory and excretory functions
- Anterior head region has sensory tentacles.
- Mouth contains a rasping organ (radula.)
- Dioecious and oviparous, usually with indirect development.
- Examples: Pila (apple snail), Pinctada (pearl oyster), Sepia (cuttlefish), Loligo (squid), Octopus (devil fish), Aplysia (sea hare), Dentalium (tusk shell), Chaetopleura (chiton).
- Echinodermata
- Have an endoskeleton of calcareous ossicles with a spiny body
- All marine with organ-system level of organisation
- Adults are radially symmetrical, larvae are bilaterally
- Digestive system has a mouth on the lower side and anus on the upper side
- Water vascular system aids locomotion, food capture/transport, and respiration
- Excretory system is absent, sexes are separate and fertilization is usually external
- Development is indirect with free-swimming larva.
- Examples: Asterias (starfish), Echinus (sea urchin), Antedon (sea lily), Cucumaria (sea cucumber), and Ophiura (brittle star).
- Hemichordata
- Considered a sub-phylum of Chordata, now a separate phylum
- Rudimentary structure (stomochord) resembles a notochord
- Worm-like marine animals with organ-system level organization
- Bilaterally symmetrical, triploblastic, and coelomate
- Body has proboscis, collar, and trunk
- Open circulatory system and respiration through gills
- Proboscis gland excretion
- Sexes are separate, external fertilization, indirect development
- Examples: Balanoglossus and Saccoglossus
- Chordata
- Presence of a notochord, a dorsal hollow nerve cord, and paired pharyngeal gill slits
- Bilaterally symmetrical, triploblastic, coelomate with organ-system level of organization
- Closed circulatory system
- Post-anal tail
Chordata Subphyla
- Urochordata/Tunicata
- Cephalochordata
- Vertebrata: Notochord replaced by a cartilaginous or bony vertebral column in adults
- Vertebrates have a ventral muscular heart (2, 3, or 4 chambers), kidneys, and paired appendages
Vertebrata Division
- Agnatha
- Lacks jaws
- Super Class - Cyclostomata
- Ectoparasites on some fishes
- An elongated body bearing 6-15 pairs of gill slits
- Sucking and circular mouth without jaws
- Marine creatures that go to freshwater to spawn
- Cranium and vertebral column are made of cartilage.
- They lack fins and scales.
- Closed circulatory system
- Larvae, after metamorphosis, relocate to the ocean.
- Examples: Petromyzon (lamprey) and Myxine (hagfish)
- Gnathostomata
- Bears jaws
- Super Class: Pisces & Tetrapoda
- Class Chondrichthyes
- Marine animals with a streamlined body and a cartilaginous endoskeleton.
- Persistent notochord.
- Gills separate
- Minute placoid scales
- Powerful teeth and jaws
- Absence of air bladder,
- Viviparous
- Examples: Scoliodon (dog fish), Pristis (sawfish), Carcharodon (great white shark), Trygon (stingray).
- Class Osteichthyes
- Marine and freshwater, streamlined body with a bony endoskeleton.
- A mouth that is primarily terminal
- Air bladder present to regulate potency
- Covered by cycloid or ctenoid
- cold blooded (poikilothermous) for most animals
- Sexes are separate
- External fertilization, oviparous
- Development is direct. -Examples: Exocoetus(flying fish), Hippocampus(seahorse), Labeo, Catla, Clarias (Amphibia
- Class Chondrichthyes
- Class Amphibia - Live in aquatic and terrestrial habitats - Limbs, the body divides into head and trunk - Moist skin with eyelids - Respiration is by gills, lungs, and skin - A tympanum in their ear - Includes a chamber called the cloaca - Three chamber heart - Fertilization is external and mostly oviparous. - Salamandra (Salamander), Ichthyophis (Limbless amphibia).
- Class Reptilia
- Covered by dry and cornified, covered in skin
- No external ear openings
- Three chambered heart
- Poikilotherms
- Snakes and lizards can shed their scale
- Examples: turtle, tortoise, chameleon, garden lizard
- Class Aves
- Birds with feathers can fly with the exception of ostriches
- Modified forelimbs into wings
- The skin is dry, save the oil gland at the tail base
- Pneumatic hollow bones
- Heart is four chambered and digestive tract contains to additional chambers
- Warm-blooded (homoiothermous)
- direct development, sexual reproduction
- Pigeon, crow, parrot, penguin, vulture.
- Class Mammalia
- Varies in locations
- Presence of mammary glands used to nourish young
- Limbs present
- Skin is filled with hair
- Mammals have 4 chambered hearts
- Lungs for respiration
- Internal fertilization and direct development occur in mammals
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