Kingdom protista

• Algae can be single-celled (unicellular) or multicellular, with some species being photosynthetic while others are heterotrophic.
• Kingdom Animalia includes various phyla:

  • Porifera (sponges)
  • Cnidaria (Hydra, jellyfish, sea-anemone)
  • Platyhelminthes (flatworms)
  • Nematoda (roundworms)
  • Annelida (segmented worms like Nereis and earthworm)
  • Mollusca (Chiton, snail, octopus)
  • Arthropoda (spiders, prawn, insects like butterfly and cockroach)
  • Echinodermata (starfish, sea-urchins)
  • Chordata (vertebrates like fish, amphibians, reptiles, birds, mammals)
• Animals in the same species can breed among themselves, but not with animals from different species
• Five Kingdom Classification of Living Organisms:

  • Kingdom Monera (Bacteria and blue-green algae)
  • Kingdom Plantae (Bryophyta, Pteridophyta, Gymnosperma, Angiosperma)
  • Kingdom Protista (Algae like Chlorophyta, Protozoa like Rhizopoda)
  • Kingdom Animalia (Porifera, Cnidaria, Platyhelminthes, Nematoda, Annelida, Arthropoda, Mollusca, Echinodermata, Chordata)
  • Kingdom Fungi (Ascomycota, Zygomycota, Basidiomycota)
• Phylum Rhizopoda (Amoeba):

  • Unicellular organism found in moist soil or water
  • Can survive extreme conditions by forming cysts
  • Moves by extending cytoplasm to form pseudopodia for feeding
• Phylum Euglenophyta (Euglena):

  • Has flagella for movement
  • Possesses both animal and plant characteristics
  • Can be autotrophic or heterotrophic
• Phylum Ciliophora (Paramecium):

  • Covered with cilia for movement and feeding
  • Contains two contractile vacuoles for osmoregulation
  • Feeding process involves ciliated oral groove and food vacuole formation
• Phylum Apicomplexa (Plasmodium):

  • Move by flexing
  • Lack specific locomotion structures
  • Produce infective agents called sporozoites
• Apicomplexans move using cilia, flagella, or pseudopodia
• They move by flexing
• Apicomplexans have an apical complex of microtubules that attaches them to their cell host
• Apicomplexans produce sporozoites, which are infective agents transmitted to the next host
• An Apicomplexan parasite causes malaria
• Life cycle of Plasmodium:

  • Sporozoites enter human blood through the bite of an infected female Anopheles mosquito
  • Plasmodium enters liver cells, multiplies, and divides to produce merozoites
  • Merozoites are released from the liver cells and enter red blood cells, where they continue to proliferate and some produce gametocytes
  • Infected red blood cells burst, releasing parasites that infect new red blood cells
  • Symptoms of malaria include a chill followed by high fever caused by toxic substances released affecting other organs
• • Uninfected female Anopheles mosquito bites an infected person, obtaining Plasmodium gametocytes along with human blood
  • In the mosquito's digestive tract, gametocytes develop into gametes and fertilization occurs
  • Zygospores embedded in the mosquito's stomach lining produce sporozoites, which are released and migrate to salivary glands
  • The cycle repeats when the infected female Anopheles mosquito bites an uninfected human
• Important phyla in Kingdom Animalia:

  • Phylum Porifera
  • Phylum Cnidaria
  • Phylum Platyhelminthes
  • Phylum Nematoda
  • Phylum Annelida
  • Phylum Mollusca
  • Phylum Echinodermata
  • Phylum Arthropoda
  • Phylum Chordata
• Phylum Porifera characteristics:

  • Multicellular, mainly marine
  • Cells do not form true tissue
  • Diploblastic animal
  • Shapes include radially symmetrical or asymmetrical
  • Body plans: asconoid, syconoid, and leuconoid
  • Bodies are perforated by tiny pores (ostia)
  • Have specialized cells called porocytes and collar cells (choanocytes)
  • Amoeboid cells function for transport of food, reproduction, and secrete skeletal material
  • Reproduce asexually and sexually
• General morphology of Sponges (Leucosolenia sp.):

  • Choanocytes consist of a single flagellum surrounded by a collar of microvilli
  • Body consists of hundreds of tiny pores (ostia)
  • Porocytes cells form the pores and regulate their diameter
  • Collar cells create water current for food and oxygen transport
  • Mesohyl supported by slender skeletal spicules
  • Amoeboid cells in the mesohyl secrete skeletal material
  • Suspension feeders
• Phylum Cnidaria characteristics:

  • Mainly marine animals, some live in freshwater
  • Radially symmetrical
  • Has tentacles surrounding the mouth
  • Gastrovascular cavity for digestion
  • Stinging cells called cnidocytes
  • Two shapes/forms: polyp and medusa
  • Classes include Hydrozoa, Scyphozoa, and Anthozoa
• Class Hydrozoa characteristics:

  • Example: Hydra sp.
  • Freshwater, polyp, solitary
  • Body wall composed of epidermis and gastrodermis with mesoglea in between
  • Epidermis contains musculo-epithelial cells, interstitial cells, cnidocytes, sensory cells, nerve cells, and mucous cells
  • Gastrodermis contains nutritive-muscle cells and enzymatic gland cells
  • Reproduces asexually through budding and sexually
• Class Hydrozoa characteristics (continued):

  • Example: Obelia sp.
  • Marine, polyp, live in colonies, larvae is a medusa
  • Colony consists of feeding polyps (gastrozooid) and reproductive polyps (gonozooid)
  • Development of a colony involves budding and continuous growth of new buds
• Class Scyphozoa characteristics:

  • Example: Aurelia sp. & Cyanea sp. (jellyfish)
  • Medusa is the dominant form in the life cycle
  • Polyp stage is small or absent
  • Medusae are larger than Hydrozoa medusae
• Class Anthozoa characteristics:

  • Example: Corallium sp. (coral), Actinia sp. (sea anemones)
  • Polyp is the dominant form in the life cycle
  • No free-swimming medusa stage
  • Reproduces sexually with eggs developing into planula larvae