Exam 3 Flashcards
Do fungi have genders?
They do not! Sexual cycles make no M/F gametes. They have no genders but instead are + or - mating types.
What are the three steps to form a zygote in fungal reproduction?
1) Plasmogamy - fusion of haploid (+) and (-) hyphae
2) Heterokaryotic stage - hyphae with unfused haploid nuclei of both types
3) karyogamy - fusion of +/- haploid nuclei to form zygote (2n)
Draw the life cycle/fungal reproduction cycle.
Check slide of cycles in the slideshow
What are Chytrids?
-basal fungus group
-Aquatic decomposers or parasites
- have flagella on their zoospores
What are zygomycetes?
- sexual cycle makes a resistant zygosporangium
- make asexual spores via mitosis called sporangiospores
- have coenocytic hyphae
What are glomeromycetes?
- mutualistic arbuscular mycorrhizae
-90% of plant species have a mycorrhizal relationship
What are ascomycetes?
- sexual spores within saclike ascus
- morels are really tasty
- asexual
What are basidiomycetes?
- has sexual spores within club-like basidium
- no asexual spores
- “mushrooms”
- has a lot of different shapes
What are the importances of fungi?
- medicine and research
- huge decomposers
- Symbioses - commensalism, mutualism
- Food
- property damage
What is the importance of fungi as decomposers?
they can break down the component of wood that most organisms cannot which is called lignin. It can feed on stumps of trees and turn it into soil.
What is the importance of fungi as property damage?
They can cause dry wall, dry rot, wet rot, mold, mildew, etc.
After floods or snow, there can be mildew. Paper in the walls have cellulose and lignin so they are susceptible to fungus.
What is the importance of fungi as mutualists?
- Mycorrhizae: fungi living in close association with almost all plant roots (80 - 90% of all plants)
-Ectomycorrhizae: fungus remains outside of - Endomycorrhizae: fungi penetrate cell wallls and form haustoria (All glomeromycetes are endomycorrhizal)
Mycorrhizal fungi help plants absorb moisture and minerals and the fungus gets sugars from the plant
Lichens: relationship between a fungus and an cyanobacteria. Fungus gives the structure, moisture and minerals. Algae/cyanobacteria gives back sugar.
Soredia can reproduce as a dual organism - a little bit of both
Which group of fungi are ALL endomycorrhizal?
glomeromyctes
What are the key “pioneers” that break down bare rock and live in harsh environments?
Lichens
What is the importance of fungi as pathogens?
- can break down/kill other plants with disease
- Some produce mycotoxins (Ex: ergot - ergotism, LSD)
- infects animals (ascomeycete/cordycepts can create zombie ants, amphibian disease)
-infecting humans:
- mycosis = infection due to fungus
- Ex: “valley fever” - dust storms in the south have fungus living in the dust and can enter our body through respiratory pathways
- Many common ones: ringworm, oral thrush, athlete’s foot, jock itch, vaginal yeast infections
What is the importance of fungi as medicine/research?
- source of antibiotics & other meds
- Ex: penicillin, cephalosporins
- yeasts: can use them to create proteins in-vitro
What is the importance of fungi as food?
- mushrooms
- morels
- truffles - ascomycetes - found underground in roots of trees and they trained pigs to find them
- yeast do fermentation: beer and bread
- Blue cheese: the blue stuff is actually spores in fungi without the fungus it’ll basically just be more like brie
- Soy sauce: fermentation of soy beans using the aspirillus fungus
What is the importance of fungi as poison?
- Moldy foods can kill humans and livestock
- Ex: Ergotism from ergot on rye
- Ex: aflatoxin from aspergillus on corn, peanuts, etc.
What qualities do chlorophytes, charophytes, and plantae share?
What do charophytes share with plantae?
- similar flagellated
Sporopellenin: druable polymer that protects - ## zygotes in charophytes
What does it take to live on land?
- motility
- water balance
- pH condition
- Structure
What was it like for the green algae who moved from water to land?
-more resources, less competition - nobody was there so
- subjected to periodic dehydration
- populations with land adaptation thrive
Advantages:
- more CO2 - no water in the way
- more minerals from the soil instead of just surrounding you in the water
Disadvantages:
- gonna dry out and get crispy without water
- no “support” in air
What classification is horsetails in and describe them?
Horsetails (Equisetum)
- have jointed hollow stems with tiny leaves (the hollow stems have a ton of silica in them)
- this is the plant in the old cartoons where they are underwater with a straw above water to breathe
What classification are ferns in and describe them?
Megaphylls developed from what?
fiddleheads
What are on the underside of the sporophylls/megaphylls?
sori
Inside the sporangea, what process has to happen to give us spores?
Meiosis - giving rise to haploid spores
What do epiphytes mean?
grows on the surface of the plant
Describe the fern life cycle?
Diploid sporophyte —> sori —> look closely at the sori —> sporangea —> meiosis making haploid spores —> spores land on moist surface and germinates into a gametophyte —> the gametophyte grows into a green blob —> has the rhizoids to stick it to the ground and contains archegonia and antheridia
What does heterosporous mean?
True or false: seed plants are heterosporus
True!
Megaspores grow into —– gametophytes and microspores grow into —— gametophytes
female, male
What is the ovule?
the megasporangium with retained megaspore + surrounding sporophyte tissue
What is pollination?
Pollens grains travel (in air or by animal) to reach ovule-bearing parts = pollination
Can you have pollination but no fertilization?
Yes! Pollination is just carrying the pollen (sperm) to the ovule but there’s no guarantee it’ll get fertilized.
True or false: Conifers and Angiosperms have flagella
False! They do not
Where do gymnosperm seeds develop from?
fertilized ovule
What parts do the ovule include?
embryo, food supply, and seed coat
How do seeds germinate in the ground when planted by a squirrel when they have no roots and no exposure to sun?
It relys on the stored energy reserves that were in the ovule when it got fertilized. Like a baby relying on a placenta. The seeds/nuts are chock full of fats and proteins and fats contain a lot of carbon which is an extremely high energy source. The coating around the seeds and the amount of nutrients they have can help them actually stay dormant for long amounts of time until the conditions are favorable to germinate.
Describe the phylum ginkgophyta
only one remaining species in this phyla - ginkgo trees (ginkgo
female trees: naked sporophylls/ovules that give rise to fleshy seeds and not fruit. They do not produce cones.
Male trees: sporophylls in strobili and the pollen is carried by the wind.
When did the cambrian explosion occur?
535 million years ago
What happened during the later paleozoic era?
fish dominated the seas
arthropods invade land - plants had already been there on land
amphibians (vertebrates) invade land
What are the mesozoic era animals?
dinosaurs, pterosaurs, aquatic reptiles
What are the cenozoic era animals?
modern animals that we know today
What is radial symmetry?
No matter which way you look at it, you get the same view (ex: sea anemone)
These animals are usually sessile (attached) or planktonic (drifting) in life
What does aboral side mean?
What is bilateral symmetry?
- usually see concentration of sensory organs on one side of the organism (usually with head–> cephalization)
- meets the world on one end
- active lifestyle
What does diploblastic mean?
- two germ layers: ectoderm and endoderm
What does triploblastic mean?
-All three germ layers: Ectoderm, mesoderm, and endoderm
How do protostomes have their mesoderm?
A ring around the base of the acrhenteron
How do deuterostomes have their mesoderm?
Forms at the tip of the archenteron
What does the mesoderm do?
Give rise to muscles and exoskeleton
What is the pseudocoelem?
a fluid-filled space between body wall and gut (digestive tract)
Purpose
- cushions internal organs
- how we are able to be pregnant
- how snakes are able to swallow eggs whole
—–> organs can move about the space because of coelem
no mesoderm around the endoderm
What are true coeloms?
Means the coelom is completely lined with mesoderm
- we as humans have this
Mesoderm helps support internal organs
gut has muscles surrounding it - peristalsis
What are acoelomates?
no coelom at all –> no body cavity
What are the protostome development patterns?
Blastopore of gastrula becomes adult mouth (mouth first)
Then anus
Cleavage is spiral and determinate
- early embroyonic cells “fated” to become certain body parts
- lose any early cell —> defect or death
What are the deuterostome development patterns?
Blastopore of gastrula becomes adult anus (anus first) then mouth —> how we as humans form
Cleavage is radial and indeterminate
- all cells can become any cell in the body
- if you lose one its not a big deal
