Protists

Parazoa

True tissues absent

General Protists Characteristics

Unicellular Small No symmetry or variety of No germ layers No tissue or organs; but specialized organelles Aquatic or Terrestrial; free-living or parasitic

Fission

Yields two essentially genetically identical individuals

Saprozoic Feeder

food particles are absorbed across the plasma membrane

Holozoic Feeders

phagocytosis, where protozoan actually eats food particles with cytostome (mouth-like) and lysosomes (stomach)

Protists: Sexual Reproduction

Conjugation or syngamy

How do protists relate to other eukaryotes?

First Eukaryotes; Reveal evolutionary history for other Eukaryotes

Flagella

A long, whip-like filament that helps in cell motility.

Phyla Ciliophora

Ciliates, use cilia for feeding and movement, develop cysts, has defined mouth and feeding organelle, free-living, asexual and sexual reproduction

Phyla within Excavata

Euglenozoa Kinetoplastida

Protists Super Groups

Excavata Aveolata Amoebozoa Rhizaria Archaeplastida

Phyla within Rhizaria

Formiferans Radiolara Actinosphaerliem

Excavata

Groove on one side of the cell body, modified (or reduced) mitochondria.

Super group Amoebozoa

Include naked and testate amebas; amebas with flagellated stages in the life cycle. Typically have branched tubular mitochodrial cristae

Cristae

Infoldings of the inner membrane of a mitochondria that houses the electron transport chain and the enzyme catalyzing the synthesis of ATP.

Endosymbiosis

Key organelles of eukaryotes originated as symbiosis between separate single-celled organisms

Eumetazoa

Members of the subkingdom that includes all animals except sponges. (true tissues)

Autotrophic

Organism that makes its organic nutrients from inorganic raw materials

Heterotrophic

Organism that obtains both organic and inorganic raw materials from the environment in order to live; includes most animals and microorganisms and those plants that do not have photosynthesis

Protists Movement

Pseudopodia, flagella and cilia

(Genus) Paramecium

Supergroup: Alveolata Phyla: Ciliophora A ciliated (it propels itself via cilia) protist that lives in fresh water and eats other tiny organisms for food.

Phyla Dinoflagella

Supergroup: Alveolata Two flagella Sexual reproduction present

Syngamy

Union of male and female gametes to form a zygote

Pseudopodia

A temporary footlike extension of a one-celled organism, such as an amoeba, used for moving about and for surrounding and taking in food

Phyla within Aveolata

Apicomplexa Dinoflegella Ciliophora

Old Classification of Protists

Based on how they move, how they eat, habitat, etc.

Protists: Asexual Reproduction

By fission, budding and cysts

New Classification of Protists

By super groups based on taxonomy and shared characteristics. Cladistics approach.

Cilia

Hairlike projections that extend from the plasma membrane and are used for locomotion

Osmotrophs

Heterotrophic organisms that absorb dissolved nutrients

Metazoa

Multicellular parasites.

Genus' within Ciliophora

Paramecium Didinium Stentor SPirostomum Vorticella

Trypanosoma

SG: Excavata Phyla: Kinetoplastida Causes African sleeping sickness in humans; spread by biting bugs

Difference between cilia/flagella vs pseudopodia?

Structurally, flagella and cilia are very similar; both are also used in feeding and locomotion. Pseudopodia are cytoplasmic extensions (caused by elongation of microtubules) that aid in feeding and locomotion.

(Genus) Plasomodium

Supergroup: Alveolata Phyla: Apicomplexa Spreads malaria

(Genus) Stentor

Supergroup: Alveolata Phyla: Ciliophora filter-feeding, heterotrophic ciliate protists. They reproduce asexually through binary fission

(Genus) Spirostomum

Supergroup: Alveolata Phyla: Ciliophora free-living ciliate protists, found in both salt and fresh water. All are elongated, flexible and highly contractile. reproduces by binary fission. Reproduction may be purely asexual, or it may follow conjugation, during which compatible mating individuals come together and transfer genetic material across a cytoplasmic link.

(Genus) Didinium

Supergroup: Alveolata Phyla: Ciliophora When it hits a Paramecium, poison darts (toxicysts) and attachment lines fire automatically

Phyla Apicomoplexa

Supergroup: Alveolata Possess alveoli (membrane bound sacs that lie beneath the plasma membrane and serve structural functions cysts present

Giardia

Supergroup: Excavata lives inside the intestines of infected humans or other animals. Individuals become infected through ingesting or coming into contact with contaminated food, soil, or water. The Giardia parasite originates from contaminated items and surfaces that have been tainted by the feces of an infected carrier

Kinetoplastida and example

Supergroup: Excavata Parasitic in plants and animals Ex Genus: Trypanosoma

Euglinida and example

Supergroup: Excavata Phyla: Euglenozoa have chloroplasts with chlorophyll, surrounded by double membrane Ex: Euglena has light sensitive stigma (eyespot) allows light from one direction to strike light-sensitive receptor

Euglenozoa

Supergroup: Excavata Presence of nucleoli during mitosis Cristae Pellicle: series of longitudinal microtubules just beneath the plasma membrane that help stiffen the membrane

Why is endosymbiosis important?

Supports evolutionary history

(Genus) Vorticella

Vorticella species mainly live in freshwater ponds and streams—generally anywhere protists are plentiful. Reproduction is by budding, where the cell undergoes longitudinal fission and only one daughter keeps the stalk. They reproduce by fission, which is also known as cell division. They are also capable of reproducing by conjugation, a form of sexual reproduction where two individuals attach at the oral groove and exchange DNA.

Super group Rhizaria

are amoeboids with filose, reticulose, or microtubule-supported pseudopods. Many produce shells or skeletons, which may be quite complex in structure, and these make up the vast majority of protozoan fossils. Nearly all have mitochondria with tubular cristae.