Ch 27: The Rise of Animal Diversity Flashcards
List the general characteristics of animals.
Multicellular; Heterotrophic; Cells lack cell walls and therefore can move during development and in the adult animal; Early development includes a blastula and typically a gastrula; Huge diversity
Describe how and why animal diversity has changed over time.
Animal diversity has been shaped by five mass extinctions followed by adaptive radiations; Most of the animal body plans seen today first evolved during the Cambrian explosion (period of land colonization)
List the characteristics associated with the major branch points on the phylogenetic tree of animal
Multicellularity - Poniferans
Multicellularity; Radial symmetry; Diploblastic - Cnidarians
Multicellularity; Bilateral symmetry; Triploblastic; Blastopore becomes anus - Deuterostomes (Echinoderms; Chordates)
Multicellularity; Bilateral symmetry; Triploblastic; Blastopore becomes mouth - Protostomes (Nematodes; Arthropods; Mollusks; Annelid worms; Flatworms)
List and describe the structure and function of the 4 major tissue types found in animal bodies.
Connective Tissues - Bone tissue; blood tissue; connective dermis tissue
Nervous Tissues - Nervous tissue in brain
Epithelial Tissues - Reproductive tissues
Muscle Tissues - Smooth muscle tissue; cardiac muscle; skeletal voluntary muscle
Describe and contrast radial and bilateral symmetry
Radial symmetry - Many planes of symmetry around the body axis
Bilateral symmetry - A single plane of symmetry runs from mouth to tail
Define cephalization and describe its relationship to bilateral symmetry
- Bilateral symmetry is correlated with cephalization (The concentration of sense organs, nervous control, etc., at the anterior end of the body, forming a head and brain, both during evolution and in the course of an embryo’s development.)
- Need to capture information from the environment: sensory receptors and to respond to it: motor functions
Identify major animal phyla that have a segmented body plan
annelids, arthropods & chordates
Define coelom and pseudocoelom
- Coelem - a body cavity, a fluid- or air-filled space located between the digestive tract and the outer body wall; A true coelom is lined on all sides by tissues derived from the mesoderm
- A pseudocoel is not lined on all sides by mesodermal derived tissues
Contrast the body plans of coelomate, acoelomate, and pseudocoelomate animals
Coelomate- Coelomates have a body cavity that is lined with mesoderm called the peritoneum. An example of a coelomate is phylum Chordata (such as tigers).
Acoelomate- Acoelomates have no true body cavity. An example of an acoelomate is phylum Cnidaria (such as sea anemones).
Pseudocoelomate- Pseudocoelomates have a pseudocoelom; that is, they have a body cavity, but it is not lined with mesoderm.
Describe the process of cleavage; Distinguish between spiral and radial cleavage
Cleavage is a series of mitotic cell divisions that transform the zygote into a blastula
Spiral cleavage - Early protostome embryo: its four cells are undergoing cleavages oblique to the original body axis
Radial cleavage - Early deuterostome embryo: its four cells are undergoing cleavages parallel with and perpendicular to the original body axis
Define blastula, blastopore, gastrula, germ layers, endoderm, ectoderm, mesoderm, diploblastic, triploblastic
Blastula - The end product of cleavage
Blastopore - the opening by which the cavity of thegastrula, an embryonic stage inanimal development, communicates with the exterior.
Gastrula - An embryonic stage in animal development encompassing the formation of three layers: ectoderm, mesoderm, and endoderm.
Germ Layers - a group of cells in an embryo that interact with each other as the embryo develops and contribute to the formation of all organs and tissues
Endoderm - the germ layer covering the surface of the embryo, gives rise to the outer covering of the animal and, in some phyla, to the central nervous system
Ectoderm - the innermost germ layer, gives rise to the lining of the digestive tract (or cavity) and to the lining of organs such as the liver and lungs of vertebrates.
Mesoderm - all bilaterally symmetric animals have a third germ layer, called the mesoderm, which fills much of the space between the ectoderm and endoderm; forms the muscles and most other organs between the digestive tract and the outer covering of the animal.
Diploblastic - Diploblastic animals have two germ layers (Endoderm; Ectoderm)
Triploblastic - Triploblastic animals have three germ layers (Endoderm; Mesoderm; Ectoderm)
Describe what happens during gastrulation and what is formed as a result of this process
In animal development, a series of cell and tissue movements in which the blastula-stage embryo folds inward, producing a three-layered embryo, the gastrula.
Distinguish (similarities and differences) between protostomes and deuterostomes
Protostomes: Spiral Cleavage; Blastopore becomes mouth; Anus forms secondarily
Deuterostomes: Radial Cleavage; Blastopore becomes anus; Mouth forms secondarily
Describe the characteristics of Ponifera
Examples: Sponges
No body plan; no nervous system; filter feeding; intracellular digestion; no circulatory system; Respiration via diffusion across the body wall; support via spicules of calcium carbonate + protein fibers;
Key structures:
- choanocytes: flagellated cells that circulate water
- ostia: pores through which water enters
- oscula: opening through which water leaves
Describe characteristics of Cnideria
Examples: Jellyfish, Corals, Sea Anemones
No body plan; nerve net; feeding via predation + mutualistic association with algae; Gastrovascular cavity; No circulatory system; Respiration via diffusion across the body wall; Support system via mesoglea + hydrostatic skeleton + hard exoskeleton
Key Structures:
- Cnidocytes: specialized cells containing cnidae. The stinging structures of jellyfish (nematocysts) are an example of these.
* Polyp: sedentary, column shaped form with oral surface facing upward
* Medusa: free-swimming, umbrella shaped form with mouth oriented downward
* Diploblastic; radial body symmetry typical
Describe characteristics of Platyhelminthes (Protostomes Lophotrochozoans)
Examples: Flatworms; Flukeworms: Tapeworms
Acoelomate body; Centralized nervous system w brain; Feeding via predation/parasitism; Gastrovascular cavity; No circulatory system; Respiration via diffusion across the body wall; Support via muscles;
Key terms:
- Triploblastic with bilateral symmetry
Describe characteristics of Annelids (Protostomes Lophotrochozoans)
Examples: Earthworms, leeches, polychaetes
Coelomate body; Centralized nervous system w brain; Feeding via everything; Complete digestive system; Closed circulatory system; Respiration via diffusion across body wall; Support via hydrostatic skeleton
Key terms
- Metamerism: segmentation
- chaetae (setae): stiff hairs/ bristles
- parapodia: paddle-like, unjointed appendages found on most segments in polychaetes; used for locomotion and gas exchange
Describe characteristics of Mollusks (Protostomes Lophotrochozoans)
Examples: Snails, Clams, Squid, Octopus
Coelomate body; Centralized nervous system w brain; Feeding via everything; Complete digestive system; Open circulatory system; Respiration via gills in aquatic forms and lungs in terrestrial; Support via hydrostatic skeleton (internal or external shell)
Key terms:
- Radula: ribbon like structure studded with teeth; used for feeding
- Mantle: fold of the dorsal body wall that protects the visceral mass and produces the shell in groups with a shell
Describe characteristics of nematodes (protostomes ecdysozoans)
Examples: Roundworms, heartworms
Pseudocoelomate; Centralized nervous system w brain; Feeding via predation, parasitism, detritivores; Complete digestion system; No circulatory system; Respiration via diffusion across body wall; Support via hydrostatic skeleton and cuticle
Key terms:
- Ecdysis: molting
- Cuticle: exoskeleton
Describe characteristics of Echinoderms (Deuterostomes)
Examples: sea stars, sea urchins, sea cucumbers, sand dollars, brittle stars
Coelomate body plan; Nerve rings; Feeding via everything depending on organism; Complete digestion system; Circulation via hemal and water vascular system (not defined well); Respiration via various specialized structures; support via endoskeleton
Key terms:
- water vascular system-system of fluid filled canals that run throughout the echinoderm body and help move the tube feet
- tube feet
Describe characteristics of Chordata (Vertebrates)
Examples: fish, amphibians, reptiles, birds, mammals
Coelomate body; Centralized nervous system with enlarged brain; Feeding via everything depending on organism; Complete digestion system; Closed circulatory system; Respiration via diffusion across skin, lungs, gills, depending on group; Support via endoskeleton, scales, exoskeleton
Terms:
Vertebrae: bone or cartilage block that forms the backbone (replaces the notochord as the supporting structure in vertebrates
Define the chordates characteristics
- 5 Key Features:
- Notochord - Flexible rod that provides skeletal support
- Dorsal, hollow nerve cord - Unique structure that develops into the brain and spinal cord
- Pharyngeal slits/pouches - Structures that function in suspension feeding, as gills or as parts of the head
- Post anal tail - Muscular tail that extends posterior to the anus
- Thyroid gland or Endostyle - The endostyle is an epithelial exocrine gland found in non-vertebrate chordates (amphioxi and tunicates) and the larvae of modern lampreys. It is generally considered to be an evolutionary precursor of the thyroid gland of vertebrates.
Distinguish (similarities and differences) between vertebrates: fish, amphibians, sauropsides (reptiles), and mammals
Amphibians - Amphibians live in the water as babies and on land as they grow older. They have smooth, slimy skin.
Birds - All birds have a beak, two legs, feathers and wings.
Fish - Fish live and breathe under water. They have scaly skin, fins to help them swim and they breathe through gills.
Mammals - Mammals are animals that breathe air, grow hair or fur and feed on their mother’s milk as a baby.
Reptiles - All reptiles breathe air. They have scales on their skin.
List the evolutionary characteristics (branching points) of vertebrates
These evolutionary developments include the following:
- A cranium → A vertebral column.
- Jaws.
- Bone.
- Limbs.
- Lungs.
- Water-tight skin.
- Amniotic eggs.
- Feathers, fur, and hair.
Define the different groups of fish
three basicfishgroups: bony fishes, cartilaginous fish,and lampreys
Bony fishes are a group of aquatic vertebrates characterized by having a skeleton made of bone.
Cartilaginous fish are so named because, instead of bony skeletons, their body frame consists of cartilage.
Lampreys are jawless vertebrates that have a long, narrow body. They lack scales and have a sucker-like mouth filled with little teeth.
Describe briefly the life cycle of amphibians
Zygote → Larvae (Aquatic) → Adults (Terrestrial) → Sperm + Egg → Zygote
Define the characteristics of the extraembryonnaires membranes of the amniotes
Amnion - Protects the embryo in a fluid-filled cavity that cushions against mechanical shock
Allantois - Disposal sac for certain metabolic waste products produced by the embryo
Yolk Sac - Contains the yolk, which is a stockpile of nutrients
Chorion -bilayered tissue derived from embryo-derived mesoderm that exchanges gases between the embryo and air
Distinguish (main similarities and differences) the 3 groups of mammals
The main difference between three mammal groups isthe way that their young develop.Monotremes lay eggs. Marsupials are born in an early stage of development, and they continue to develop in the pouch on the mother’s body. Placental mammals develop inside a mother’s body until they develop completely.
NOTES
- Sponges differ from other animals in that their simple body structure has no true tissues and they have no symmetry.
- The chorion is the outermost extraembryonic membrane of the amniotic egg.
- Cnidarians have radial symmetry, two germ layers, and a gastrovascular cavity.
- Lizards are not in the same clade within the reptiles as crocodilians (crocodiles and alligators), dinosaurs, and birds.
- Invertebrates include all animals without backbones.Only one animal phylum, Chordata, includes vertebrates, animals with a backbone (most of these are members of the subphylum Vertebrata).
