Lecture 4 OD exam Flashcards
What are the two clades within Unikonta?
Amoebozoa and Opisthokonts
The fusion of the DHFR and TS genes means what for the phylogeny of Eukaryotes?
The fusion of DHFR-TS tells us that the four non unikonta clades are relatives somehow
The genes were only inherited by Excavata, Chromalveolata, Rhizaria, and Archaeplastida
What are the three groups of amoebozoans?
gymnamoebas, entamoebas, and slime molds
Describe the two types of slime molds.
Plasmodial slime molds
- Come together in one big mass/blob and
not separated
- All nuclei are together inside one
mass/blob
Cellular slime molds
- The come together/aggregate, but are still separated by their cell walls
Still a big mass, but their nuclei are separated
Describe the life cycle of a cellular slime mold
Cellular slime molds form multicellular aggregates in which cells are separated by their membranes
Cells feed individually, but can aggregate to form a fruiting body
Dictyostelium discoideum is an experimental model for studying the evolution
Why aren’t there more cellular slime mold cheaters to avoid being a stem?
Altruism
Individual selection
they can recognize the cheaters and kick them out!
Gymnamoebas live where
Soil, fresh, water and marine environments
Entamoebas live where?
Parasites on vertebrates and some invertebrates
What are 2 diseases that entamoebas cause?
Histolytic causes amebic dysentery, and Acanthamoeba a waterborne eye pathogen
How many times has multicellularity evolved in the opisthokonts?
2
Back to slime molds: Kin selection might help explain the apparent sacrifice of the stalk/base amoebas in the cellular slime mold Dictyostelium discoideum. What idea did the recent paper we discussed in class support? (betterment of the species, altruism, individual selection, or drift)
alturism
True or False:
We are just learning about this recently but mycorrhizal fungi can connect whole forests of trees. The trees may use this “wood wide web” to communicate danger to each other, steal nutrients, share nutrients, bequeath resources before death, and may even recognize offspring and help them out.
True
What does opisthokont mean - literally?
posterior end
label and describe a general life cycle for a fungus.
look at slides
What are the two types of mycorrhizae? How do they differ?
- Ectomycorrhizal fungi form sheaths of hyphae over a root and also grow into the extracellular spaces of the root cortex.
- Arbusclar mycorrhizal fungi extend hyphae through the cell walls of root cells and into tubes formed by invagination of the root cell membrane
Cell walls of fungus are made of
chitin
What are haustoria?
specialized hyphae that allow them too penetrate into tissues of their host
what is heterotrophy
An organism that is dependent on complex organic substances for nutrition because it cannot synthesize its own food
What happens during plasmogamy?
the union of two mycelia
How do fungi recognize each other? (what’s the chemical called?
pheromones
What happens during karyogamy?
fusion of nuclei
What’s a mold?
Produce haploid spores by mitosis and form visible mycelia
What’s a yeast?
Instead of producing spores, yeasts reproduce asexually by simple cell division and the pinching of “bud cells” from a parent cell
What are Chytrids and how do they get nutrition?
They can be decomposers, parasites, or mutualists * Molecular evidence supports the hypothesis that chytrids diverged early in fungal evolution * Chytrids are unique among fungi in having flagellated spores, called zoospores
What is a zygomycete? Give an example
Type of fungi named for their sexually produced zygosporangia. Zygosporangia are resistant to freezing and drying, so can survive in unfavorable conditions
Include fast growing molds, parasites and commensal symbionts
What is Pilobolus? Why do they face light?
A zygomycete fungi that can actually aim their sporangia toward conditions associated with good food sources.
Towards light=grass=cows= dispersal