Eukaroytes: The Alveolates

• What is a key feature of eukaryotes mentioned in the material?

  Eukaryotes acquired features from Archaea and bacteria
• What are many eukaryotes classified as?

  Not animals, plants, or fungi
• When did major eukaryote lineages diversify?

  During the Precambrian period
• What major Earth events affected evolution?

  Continental collisions and volcanic eruptions
• What was the only type of organism on Earth from ~3.5 to ~2.1 billion years ago?

  Early prokaryotes
• What did prokaryotes transform on Earth?

  Life on Earth
• What type of bacteria generated oxygen?

  Cyanobacteria
• What did increased atmospheric O₂ lead to?

  Evolution of large eukaryotic cells
• What era saw extensive diversification of multicellular life?

  The Cambrian period
• What characterized the Mesozoic era?

  Distinct terrestrial biotas evolved on each continent
• How many mass extinctions occurred in the Paleozoic and Mesozoic eras?

  Five mass extinctions
• What are the two periods of the Cenozoic era?

  Tertiary and Quaternary periods
• What emerged during the Cenozoic era?

  Modern biota, including mammals and flowering plants
• What is the traditional term for many eukaryotes that are not plants, animals, or fungi?

  Protists
• What is the origin of the modern eukaryote cell based on?

  Five key steps in evolution
• What is one of the key steps in the origin of the modern eukaryote cell?

  Origin of flexible cell surface
• What is primary endosymbiosis?

  Engulfment of one cyanobacterium by a larger eukaryotic cell
• What did primary endosymbiosis give rise to?

  Chloroplasts of red algae, green algae, and land plants
• What is secondary endosymbiosis?

  Engulfment of a photosynthetic eukaryote by another eukaryote
• What is tertiary endosymbiosis?

  Engulfment of a protist that had acquired chloroplasts
• How many major clades are most eukaryotes classified into?

  Eight major clades
• When did major eukaryote lineages begin to diversify?

  1.5 billion years ago
• What are some characteristics of protist eukaryotes?

  Diverse body forms and nutritional lifestyles
• What is a defining feature of multicellularity in eukaryotes?

  Arose many times in evolution
• What is the continuum mentioned in multicellularity?

  Between fully integrated multicellular species and loosely integrated colonies
• What are the three groups of Alveolates?

  Dinoflagellates, apicomplexans, ciliates
• What do Alveolates possess beneath their cell membranes?

  Sacs called alveoli
• What is a characteristic of dinoflagellates?

  Mostly marine and photosynthetic
• What color are the chloroplasts of dinoflagellates?

  Golden brown
• What do some dinoflagellate species cause?

  Red tides
• What is the defining characteristic of apicomplexans?

  All are parasitic
• What is the apical complex in apicomplexans?

  A mass of organelles at the apical end
• What is a complex life cycle in apicomplexans?

  Includes sexual and asexual reproduction
• What is a defining feature of ciliates?

  Numerous cilia
• What is the defining characteristic of Paramecium spp.?

  Slipper-shaped cell covered by pellicle
• What do trichocysts in ciliates do?

  Act as defensive organelles
• What is the function of the contractile vacuole in ciliates?

  Osmoregulation
• What is the function of the digestive vacuole in ciliates?

  Endocytosis and digestion
• What are the main groups of eukaryotes discussed in the material?

  • Alveolates
  • Dinoflagellates
  • Apicomplexans
  • Ciliates
  • Stramenopiles
  • Excavates
  • Rhizarians
  • Plants
  • Amoebozoans
  • Fungi
  • Animals
• What are the key steps in the origin of the modern eukaryote cell?

  1. Origin of flexible cell surface
  2. Origin of cytoskeleton
  3. Origin of nuclear envelope
  4. Appearance of digestive vacuoles
  5. Acquisition of organelles via endosymbiosis