Skip to main content
Indietro

General Biology: Animal Diversity and Evolution

I pulsanti di controllo sono stati cambiati in modalità "navigazione".
1/20

Termini in questo insieme (20)

  • What are the defining features of animals?
    Animals are multicellular eukaryotes that are heterotrophs ingesting food, have cells that lack cell walls, bodies held together by structural proteins like collagen, and possess nervous and muscle tissues.
  • What is the typical animal life cycle regarding reproduction?
    Most animals reproduce sexually, with a dominant diploid (2n) stage. Gametes (n) are produced directly by meiosis.
  • What is cleavage in animal development?
    Cleavage is the rapid cell division of the zygote (2n) after fertilization, leading to the formation of a multicellular, hollow blastula.
  • What is gastrulation?
    Gastrulation is the process where the blastula folds inward to form a gastrula with distinct embryonic layers: ectoderm, endoderm, and sometimes mesoderm.
  • What is the role of Hox genes in animals?
    Hox genes regulate the development of body form and are highly conserved, enabling a wide diversity of animal morphology.
  • Who are the closest living relatives of animals?
    Animals' closest relatives are choanoflagellates, a group of suspension-feeding protists.
  • What is the significance of the Cambrian explosion?
    The Cambrian explosion (~535-525 mya) marks the earliest fossil appearance of many major animal groups, including those with mineralized skeletons.
  • What is radial symmetry in animals?
    Radial symmetry means body parts are arranged around a single central axis, common in sessile or planktonic animals, with no distinct front or back.
  • What is bilateral symmetry in animals?
    Bilateral symmetry means animals have two-sided symmetry with distinct right and left sides, dorsal and ventral surfaces, and anterior and posterior ends.
  • What are the three germ layers in triploblastic animals?
    Triploblastic animals have three germ layers: ectoderm (outer layer), endoderm (inner layer), and mesoderm (middle layer forming muscles and organs).
  • What is a coelom?
    A coelom is a true body cavity, a fluid- or air-filled space between the digestive tract and the outer body wall, lined by mesoderm.
  • What is the difference between coelomates, acoelomates, and pseudocoelomates?
    Coelomates have a true coelom; acoelomates lack a body cavity; pseudocoelomates have a body cavity not fully lined by mesoderm.
  • What distinguishes protostome and deuterostome development?
    Protostomes have spiral, determinate cleavage, coelom forms by splitting mesoderm, and blastopore becomes the mouth. Deuterostomes have radial, indeterminate cleavage, coelom forms by mesoderm budding, and blastopore becomes the anus.
  • What are the three major clades of bilaterian animals?
    The three major bilaterian clades are Lophotrochozoa, Ecdysozoa, and Deuterostomia.
  • What is the significance of the Paleozoic era in animal evolution?
    During the Paleozoic era (541-252 mya), animal diversity increased, major groups appeared, and animals began transitioning onto land.
  • What happened during the Permian mass extinction?
    The Permian mass extinction (~251 mya) caused up to 95% marine species and 70% terrestrial vertebrates to go extinct, including the only known insect mass extinction.
  • What characterizes the Mesozoic era in animal history?
    The Mesozoic era (252-66 mya) saw the dominance of dinosaurs, emergence of coral reefs, evolution of first mammals, and diversification of angiosperms and insects.
  • What defines the Cenozoic era in animal evolution?
    The Cenozoic era (66 mya-present) followed mass extinctions, with mammals increasing in size and abundance and global climate cooling.
  • What is the function of the blastopore in protostomes and deuterostomes?
    In protostomes, the blastopore develops into the mouth; in deuterostomes, it develops into the anus.
  • What is a larval stage in animal development?
    A larva is a sexually immature, morphologically distinct stage that undergoes metamorphosis to become a juvenile resembling the adult.