Biol 1263 Flashcards
Explain Cellularization Theory
Ancestral multinucleated protist evolved internal
membranous partitions around each nucleus
* Operations of each nucleus confined to discrete
regions
* Even in the extant multinucleate protists:
* No evidence of compartmentalization
* No evidence that it ever occurred
* Zelleriella sp. Flagellated multinucleate
* Chaos chaos Amoebiod
Explain Colonial Theory
- Division products of a single individual
could have remained together- colony - Multicellularity-via a colonial stage
- Hollow sphere of colonial flagellated cells
developed anterior and posterior
orientation. - Evidence:
- More than 50% of protists form
colonies where differentiation into
distinct cell types has occurred - Theory is favoured by
protozoologists- - ancestral protozoan….
Choanoflagellate
List features of fungi shared with animals
- Fungi lack chloroplasts
- Heterotrophic organisms
Require pre-formed organic compounds as energy
sources. - Produce storage compounds, including glycogen, which
is also found in animals.
List features of fungi shared with plants
- Like plants: Fungi possess a cell wall and vacuoles.
- They reproduce by (both sexual and asexual means), and
like basal plant groups (such as ferns and mosses)
produce spores. - Similar to mosses and algae, fungi typically have haploid
nuclei.
Unique features of fungi
- The fungal cell wall is composed of glucans and chitin;
while the former compounds are also found in plants
and the latter in the exoskeleton of arthropods - Fungi are the only organisms that combine these two
structural molecules in their cell wall. - Unique body form-hyphae and mycelium
- Primary decomposers
- In contrast to plants fungal cell walls do not contain
cellulose.
What does Ameoboid protozoa use to move and how does it work?
Psuedopodia,
“Front
-contraction” theory
* At anterior end: endoplasmic
proteins undergo contraction to
form ectoplasm
* At posterior end: ectoplasm is
liquified during change to
endoplasm
* Animal is pulled forward by
contraction at anterior end
What is the function of mycorrhizae in fungi?
Mycorrhizae are mutualistic relationships between fungi and plant roots. In these associations, the fungus assists the plant by expanding its root surface area, while the plant supplies the carbohydrates necessary for fungal growth
The three theories of multicellularity are?
Symbiotic, Colonial, and Cellularization
what are Foraminifera shells made of?
Foraminifera create shells (tests) out of calcium carbonate, sometimes reinforced with sand. These shells accumulate over time and contribute to chalk formations like the Cliffs of Dover.
Describe the difference between naked and shelled amoebae.
Naked amoebae (e.g., Amoeba proteus): Lack a protective shell and live in water, soil, or as parasites.
Shelled amoebae (testate amoebae, e.g., Arcella): Have a protective shell (test) made of chitin, silica, or foreign particles. Their pseudopodia extend through an opening in the shell for movement and feeding.
How do trichocysts assist ciliates in feeding?
Trichocysts are small, spike-like organelles in ciliates like Paramecium.
They can shoot out filamentous threads that help:
Anchor the ciliate to a surface.
Capture prey by trapping or immobilizing small organisms.
Defense against predators.
Explain Symbiotic Theory
Different types (species) of protists (symbiotically), form a composite
organism
* At the sub-cellular level
* eukaryotic cell formed from prokaryotes (chlorolast,
mitochondrion, nucleus, etc.) – “urkaryotes”
Some evidence to support this theory; not conclusive
* At the cellular level
* Lichens from algal and fungal partners
* Genetic problems – protists / fungi are genetically distinct organisms
* In order to reproduce the lichen disassociates; algal and fungal parts,
Reproduce separately and re-associate to form new colonies
Lichens very successful but little evidence to support this theory- Not
one organism.
