The Origin and Diversification of Eukaryotes Flashcards
What are the types three types of origin of life?
Bacteria, Eukarya, Archea
What do we call eukaryotes that are not plants, animals, or fungi?
Protists
What are monophyletic?
Eukaryotes
What is mostly more related to Archea than Bacteria?
Eukaryotes
What two things are derived from bacterial lineages?
Mitochondria and Chloroplasts
What resulted in the loss of rigid cell walls?
Cell membrane to fold inward and create surface area which resulted in larger cells
What gave rise to mitochondria and chloroplasts?
Endosymbiosis
What resulted in the increased compartmentalization and complexity?
Development of complex cytoskeleton
Formation of ribosome studded internal membranes
The enclosure of DNA in a nucleus
Where did cytoskeletons evolve?
Prokaryotes
What did the development of microfilaments and microtubules do?
Allowed changes in Shape, Distribution of daughter chromosomes, movement, and eukaryotic flagella
What did nuclear envelope do?
Developed in eukaryote evolution, arising from DNA attached to the membrane, Prokaryote DNA is attached to the inner plasma membrane.
Phagocytosis
Ability to engulf and digest other cells
Endosymbiosis
A proteobacterium was incorporated and evolved into mitochondrion
What was the original function of mitochondria?
Detoxify the O2 produced by cyanobacteria. Later coupled with formation of ATP
Primary endosymbiosis
A cyanobacterium was engulfed by a larger eukaryotic cell
Where can the remnants of peptidoglycan be found?
Glaucophytes
How many membranes do chloroplasts have?
Two
Secondary endosymbiosis
A eukaryote is engulfed a green alga cell which became chloroplast.
What do the chloroplasts of Euglenoids have?
Three membranes
Tertiary Endosymbiosis
Dinoflagellate lost chloroplast and took protist that had acquired chloroplast through secondary endosymbiosis
Protists Eukaryotes
Unicellular and microscopic (microbial eukaryotes)
Some are multicellular and large (giant kelp)
Major groups of Eukaryotes
Plantae, Fungi, Choanoflagellates, Animals
Unicellular Eukaryotes
Associate in colonies, continuum from unicellular to fully multicellular.
Alveolates
Beneath cell membrane.
- Dinoflagellates
- Apicomplexans
- Ciliates
Dinoflagellates
Photosynthetic, primary producers in oceans.
- Cause red tides
- Endosymbionts with invertebrates
- Some nonphotosynthetic parasites
One flagellum of Dinoflagellates
Originates within equatorial groove and provides thrust and spin to the organism
Second flagellum of Dinoflagellates
Originates in the longitudinal groove and acts like the rudder of a boat.
Apicomplexans
Obligate parasites
Apical Complex
Organelles at the tip of the cell that help it invade host tissue
Plasmodium
Produces malaria
Ciliates
Numerous hairlike cilia ( identical to eukaryotic flagella)
Ciliates include:
- Complex body forms and two types of nuclei
- Heterotrophic; some have photosynthetic endosymbionts
Tetrahymena Thermophila
Model organism for research on gene expression and structure and function of microtubule arrays
Didinium Nasutum (barrel)
Feeds on other ciliates and cilia occur in two separate bands.
Euplotes
Fuse into flat sheets that direct food particle into an oral groove
Paramecium
A ciliate covered by a flexible pellicle with trichocysts - defensive organelles.
Paramecium includes:
- Lives in fresh water: Contractile vacuoles excrete excess water taken in by osmosis.
- Digestive Vacuoles
Stramenopiles
Rows of tubular hairs on the longer of their two flagella. Some lack flagella, but descended from ancestors that possessed them.
Stramenopiles include:
Diatoms
Brown algae
Oomycetes
Diatoms
Unicellular, some species associate in filaments carotenoids give them a yellow or brownish color.
Diatoms include:
- Lack flagella except male gametes
- Deposit silicon dioxide in two piece cell walls
- Reproduce both sexually and asexually
Brown Algae
Brown color comes from the carotenoid fucoxanthin
Brown algae includes:
- Multicellular, marine
- Develop holdfasts with alginic acid to glue them to rocks
- Alginic Acid is an emulsifier
Oomycetes
Water molds, downy mildews.
Oomycetes include:
- Absorptive heterotrophs- digest large food molecules into smaller molecules
- Water molds- aquatic and saprobic ( feed on dead organic matter)
Rhizaria
Unicellular and mostly aquatic; long and thin pseudopods
Rhizaria include:
Cercozoans
Foraminiferans
Radiolarians
Foraminiferans
External shells of calcium carbonate
Farominiferans include:
- Brached pseudopods form sticky nets to catch smaller plankton.
- Shells have produced world’s limestone
Excavates include:
- Diplomonads
- Parabasalids
- Euglenids
- Kinetoplastids
Diplomonads and Parabasalids
Unicellular and lack mitochondria
Giardia Lambia
Causes intestinal disease giardiasis
Parabasalids
Undulating membranes that aid locomotive
Trichomonas Vaginalis
Causes trichomoniasis
Giardia
Dimplomand, has flagella and two nuclei
Trichomonas
Parabasalid, flagella and undulating membranes
Euglenids and Kinetoplastids
Mitochondria with disc shaped cristae and flagella with a crystalline rod.
Eugleinds
Some heterotrophic or photosynthetic.
Euglena
Second flagellum is rudimentary and primary flagellum orignates at the anterior of organism and trails toward posterior.
Kinetoplastids
Parasites with two flagella
What does mitochondrion have?
Kinetoplast that contains multiple circular DNA molecules
Typanosomes
Pathogens
Three kinetoplastid Typanosomones
Typanosoma Brucei
Typanosoma Cruzi
Leishmania Major
Trypanosoma Brucei
Sleeping sickness
Trypanosoma Cruzi
Chagas’ Disease
Leshmania Major
Leishmaniasis
Amoebozoans
Amoeboid body form; lobe-shaped pseudopods
Amoebozoans include:
Loboseans
Loboseans
Feed by phagocytosis, engulfing smaller organisms and particles with pseudopods.
Loboseans include;
Living on the bottoms
Testate amoebas live in shells made from sand grains or secreted by organisms
Asexual Reproduction
- Equal splitting by mitosis followed cytokinesis.
- Splittting once cell into multiple cells
- Budding
- Sporulation
Budding
Outgrowth of a new cell from the surface
Sporulation
Formation of specialized cells that can develop into new individuals
Offspring from asexual reproduction
Genetically identical-clonal lineages.
Reproduction in Patamecium
- Two types of nuclei
- Asexual Reproduction
Conjugation
Two individuals fuse and exchange micronuclei; a sexual process, but not reproductive
What happens in the exchange of micronuclei in Paramecium?
Genetic recombination, after conjugation, cells separate and continue their lives as two individuals.
Alternation of Generations
- Diploid gives rise to haploid.
- Haploid and diploid may reproduce asexually
- Occurs in protists, plants and some fungi.
Heteromorphic
Two generations differ morphologically
Isomorphic
Two generations are similar
Sporocytes
Diploid organism, divide meiotically produce haploid spores.
Spores develop
Haploid organims
Haploid organism produce
Gametes, by mitosis and cytokinesis
Gametes fuse
Produce diploid organism
Primary producers in aquatic ecosystems
Phytoplankton
How much do diatoms perform in carbon fixation ?
1/5, same amount as the rainforests.
Phytoplankton includes
Contribute to global photosynthesis
Some Microbial eukaryotes
Pathogens
Plasmodium
Parasites that cause malaria.
Phytoplankton result in
Red tide and toxins produced that can kill or harm vertebrates.
Microbial eukaryotes live as
Endisymbionts
Photosynthetic Dinoflagellates
Endosymnionts in coral
Diatoms store energy
As oil
Foraminiferan Shells
Make up extensive limestone deposits.
