Final Flashcards
Fungi are _______(cells never have more than one flagellum)
More specifically, they are ________(the single flagellum is always located at the posterior end of the cell)
Unikonts
Opisthokonts
The common ancestor of the opisthokonts was likely _______ and _______.
unicellular and flagellated
Evolutionist believe the common ancestor of opisthokonts was unicellular, which suggests __________ evolved in fungi and animals independently.
multicellularity
Evolutionists believe fungi arose around ______ mya.
460
For nutrition, all fungi are __________.
absorptive heterotrophs
-more specifically, absoptive chemotrophs
Define absorptive heterotroph
A feeding strategy where an organism absorbs small organic compounds from enviroment and uses them for both energy and carbon source.
Many fungi secrete ________ into the environment to break down large organic molecules into small molecules that they can absorb.
enzymes
What 3 types of fungi exist and what do each absorb?
- Decomposers - break down dead organic matter (e.g. animal flesh, fruit, plant cellulose or lignin…) and absorb the products
- Parasits/pathogens - absorb small organic molecules from living cells
- Mutualists - absorb small organic molecules from living host, BUT also do something positive for the host
Fungal cells have cell walls that include the molecule _______.
chitin - a fibrous polysaccharide
What are the 2 major body forms of fungi?
- Unicellular fungi (yeasts) - unicellularity seems to have evolved several times in fungi (the common ancestor of the fungi was multicellular)
- Multicellular fungi - made of many tubular filaments called hyphae, which form a mass called mycelium
The common ancestor of the fungi was _____cellular.
multi
Hyphae forms a mass called _______.
mycelium
What are the two different forms of hyphae?
- Some hyphae are septate – the cells are separated by incomplete cross-walls called septae. Pores in the septae are pretty large, and sometimes allow nuclei to move from cell to cell.
- Some hyphae have no septae – these are known as coenocytic fungi. They basically consist of one large cell with many nuclei.
Septate hyphae contain ______, or cross wall that separate nuclei.
septae
Coenocytic are one large cell with many _______.
nuclei
The production of haploid ________ is important to most fungi.
nuclei
Unicellular fungi may reproduce asexually via ______ (simple
“fission”, or sometimes “budding”)
mitosis
Multicellular fungi may reproduce asexually by simply ________ into several parts; each part continues growing.
breaking
Sexual reproduction in fungi starts with __________, when two haploid fungi fuse.
karyogamy
Decomposers play an important role in the environment by:
- Getting rid of dead organisms
- Helps form the soil
- Recycles minerals and other nutrients (e.g. fungi respire CO2 into atmosphere)
Some hyphae produce __________, projections that press into plant cells without breaking through the plasma membranes
haustoria
What are mycorhizae fungi?
Fungi that interact with plant roots; fungal hyphae form huge surface area of rootlike structure that provides water and minerals to plant, and plant provides photosynthate.
What are the two types oif mycorhizae?
- Ectomycorhizae - fungal hyphae wrap around the plant roots but do not penetrate plant cells
- Arbuscular - fungal hyphae penetrate into the root and enter the cell walls
Mycorhizae are essential for almost all _______ plants.
vascular
_________ fungi live in the above-ground parts of plants.
Endophytic
- these may be commensals or mutualists; exact relationship to host plant often not known
Lichens are stable symbioses formed by a ________ + a __________.
a fungus + a photosynthetic organism (a cyanobacterium or green alga, or both)
What are good indicators for air pollution since they can’t get rid of heavy metals and other toxins they absorb?
Lichens
Lichens can reproduce asexually by ___________, or by producing __________- a few photosynthetic cells bound by fungal hyphae
fragmentation
soredia
What are some characteristis of chytrids?
- ALL aquatic
- can be unicellular/multicellular
- decomposers, parasites, and mutalists
What are some characterists of zygomycetes?
- ALL terrestrail (moist places)
- some decomposers, parasits or commensals
- hyphae are coenocytic
When there is lots of food, zygomycetes reproduce _________.
asexually
-hyphae form sporangia and make spores by mitosis
When food is scarce, zytomycetes reproduce _______.
sexually
Describe sexual reproduction in zygomycetes
- Hyphae of two mating types grow towards each other
- Form gametangia which fuse to make zygosporangium (n+n)
- Haploid gamete nuclei in the zygosporangium fuse (karyogamy)
- Haploid sexual spores are released
80% of all known plant species form mutualistic symbioses with __________.
glomeromycetes
Almost all _________ are mutualistic symbionts of plants, forming arbuscular mycorhizae
glomeromycetes
What two synapomorphies link ascomycetes and basidiomycetes?
- ALL have septate hyphae
- They have a dikaryon stage
What is a dikaryon stage?
A stage after plasmogamy and before karyogamy, where two (and only two) genetically different haploid nuclei coexist in each hyphal cell
_________are also known as “sac fungi”, since they form small sacs (asci; singular ascus) in which meiosis occurs to produce ascospores.
Ascomycetes
For ascomycetes, asexual reproduction happens by the formation of ________
conidia (haploid spores)
What gives some mold their color?
conidia
For ascomycetes, sexual reproduction happens when ____________ which results in _______________.
haploid hyphae fuse (plasmogamy)
8 haploid ascospores
What are ascocarps?
The fruiting bodies of some multicellular ascomycetes
Penicillin is produced from what ascomycetes fungus?
The green mold Penicillium
Yeasts (unicellular fungus) reproduce asexually by ________.
budding
For ascomycetes, describe sexual reproduction
- Cells of different mating types fuse
- Zygote nucleus undergoes meiosis to form ascospores
- The whole cell is the ascus
What type of fungi do we typically think of as mushrooms?
basidiomycetes
Describe reproduction in basidiomycetes
ONLY reproduce sexually
- Haploid hyphae fuse (plasmogamy)
- Dikaryotic hyphae form a fruiting body (basidiocarp), which bears many basidia
- Karyogamy occurs, making a single diploid nucleus in each basidium; this undergoes meiosis, making 4 haploid cells, each of which becomes a basidiospore
In contrast to plants and fungi, animals cells lack a __________.
Cell wall
Animals are heterotrophsby _______, fungi are heterotrophs by __________.
ingestion
absorption
What is the significance of a short-lived diploid state in fungi?
Generate genetic variation
Which are two possible relationships between plants and fungi?
- Plants depend on fungi as mutualistic symbionts
- Plants are harmed by fungal pathogens
Gastrulation is the process that directly forms the ________
primary germ layers
The earliest ancestors of about 50% of all extant animal phyla can be traced back to the _____ explosion.
Cambrian
____________ are sister-taxon to the animals.
choanoflagellates
What is the key difference between a coelom and a pseudocoelom?
- Coelom is completely lined with mesoderm tissueand
- Pseudocoelom IS NOT completely lined by mesoderm layer
Which feature of deuterostome development explains the formation of identical human twins?
Deuterostomes have indeterminate development
Cnidarians have a _____________, which is the digestive compartment of cnidarians.
Gastrovascular cavity
The animal phylum most like the protists that gave rise to the animal kingdom is ___________.
Porifera (sponges)
Choanoflagellates are _________ feeders
suspension
Describe the morphology of choanoflagellates.
Cells with one flagellum, surrounded by a ring of microvilli
Multicellularity evolved in _______ and ________.
Fungi and animals
How did multicellularity arise in the common ancestor of the animals?
The evoloution of:
Cell adhesion proteins- proteins that allowed cells to stick together
Cell junctions
Cell signalling pathways- cell communication
What are cadherins?
Cell adhesion proteins found in ALL animals.
Animals are a ____________ taxon
monophyletic
What do animals cells have to choanoflagellates do not which allows for cell ahesion (multicellularity)?
Cytoplasmic cadherin domain (CCD)
What synapomorphies of the animals differentiate them from choanoflagellates and other eukaryotes?
- Unique cell junctions
- Extracellular matrix molecules (collagen)
- Cell ahesion molecules (CCD-cadherin)
- Cell signaling pathways
What are some features of animals?
- ALL multicellular
- All chemohetertrophs
- All digest food internally
- Specialized cells for electical signals (nerve) and contract (muscle)
- Have Hox genes - control patterning of embryo
How can we categorize animal diversity?
- Body symmetry - radial or bilateral
- Cleavage patterns - radial or spiral
- Number of embryonic tissue layers
- Fate of blastopore
- Body cavities
Bilateral symmetry is associated with _____________, a brain.
cephilization
Radially symmetrical animals tend to be _________.
sessile
If only two embryonic tissue layers (ectoderm and endoderm) are formed, the animal is called a _____________.
If a 3rd layer (the mesoderm) is formed between the other two, the animal is called a ______________.
diploblast
triploblast
Compare radial cleavage and spiral cleavage
Radial - all divisions are parallel/perpendicualr to AV axis
Spiral - Starting from 3rd division, all divisions are slightly off-parallel/perpendicular from AV axis
Radial cleavage is associated with _______________ development.
Indeterminate
Each cell in 2 and 4 cell stage can develop into complete organism (twins)
Spiral cleavage is associated with ____________ development.
determinate
Each cell in 2 and 4 cell stage is determined for specific function
The zygote undergoes cleavage to form the _________.
blastula
The hollow space inside the blastula is called the ____________.
blastocoel
When cells from the outside of the blastula move into the blastocoel, this is called ____________.
gastrulation
The endoderm surrounds a space called the __________, and connects
to the outside via the __________.
archenteron
blastopore
In __________, the blastopore becomes the mouth.
Protostomes (mouth first)
In __________, the blastopore becomes the anus.
deuterostomes (mouth second)
What are the 3 types of body cavities in animals (in addition to the gut)?
acoelomate: no fluid-filled cavity - Full of mesoderm
pseudocoelomate: there is a fluid-filled cavity between gut and ectoderm… but it is not completely lined by mesodermal tissue
coelomate: there is a fluid-filled cavity between gut and ectoderm… and it is completely lined by mesodermal tissue called peritoneum
Protostome development is correlated with ________ cleavage.
Spiral (determinate)
Deuterostome development is correlated with __________ cleavage.
Radial (indeterminate)
For protostomes, the coelom is formed by the splitting of the ______________.
mesoderm
For deuterostomes, the coelom is formed from folds of ______________.
archenteron
Compare direct and indirect development
Direct development:
zygote → embryo → juvenile → adult
Indirect development:
zygote → embryo → larva → juvenile → adult
What is a larva stage?
Stage where organism looks very different than juvenile/adult stage and undergoes metamorphosis
For animals that are sessile as adults, dispersal usually takes place in the ________ stage.
larval
Vertebrates are a subgroup of the phylum __________.
Chordata
Animals in the clade Bilateria are __________ symmetirical ______blasts.
bilaterally
triploblasts
What are 5 features of sponges?
- Asymmetric (neither radial nor bilateral)
- no true tissue layers (so neither diplo nor triploblastic)
- no digestive system
- no nerves
- no muscles
Compare unitary and colonial animals
Unitary - one individual (humans, birds)
Colonial - adult is composed of many “individual animals” that function together
What are the 3 cell layers for Porifera (sponges)?
- Outer layer - epidermis (pores)
- Middle layer - mesohyl (spicules + spongin)
- Inner layer - choanocytes (look like choanoflagellates)
Porifera are __________ feeders.
suspension