afl quiz 8

Why does the spring diatom bloom in deep water situations (oceans and deep lakes) occur just AFTER spring turnover, rather than during the turnover as it does in freshwater ponds and shallow lakes?

The overturning can be too deep for diatoms to survive.

Name any particular type of place in the ocean that has more productivity (meaning more carbon formed into sugar through photosynthesis) than most places in the ocean, and explain why that place or type of place has such high productivity.

Near the coasts, when the shape of the coast is such that incoming water currents push against the continent and bring nutrients from the depths toward the surface of the water  Those currents can also keep algae in this coastal zone, so they don't suffer the misfortune of sinking away into deeper water.

Tropical ocean and lakes.  

no overturn

Subtropical ocean and lakes (Florida, Cuba, etc.).

winter overturn (monomictic)

 

Temperate zone ocean and lakes (our area). 

spring and fall overturn (dimictic

polar oceans and lakes

summer overturn (monomictic)

Name any two major groups of algae (phyla or, if you prefer, classes, such as the particular class that includes seaweeds in green algae) that are more common in oceans than in freshwater.  (Groups in red on slide 1 of the powerpoint)

rhodophyta and dinophyta

In prymnesiophytes (Phylum Prymnesiophyta), how does the haptonema get hold of food and what exactly does it do with the food?

The haptonema reaches out and grabs food through adherence, the particle aggregation center then moves to the tip of the haptonema to capture the food. The haptonema then curves itself to deposit the food in the food vacuoles.

What other useful thing does the haptonema do?

Sensory function: coils on contact w/ objects signaling to adjust the movement of the cell.

 

Why do some prymnesiophytes, also called coccolithophorids, form good fossils?

they crystalize 

One toxin, prymnesin, specifically affects animals with gills such as shellfish, fishes, and tadpoles.  What does the toxin do that kills those creatures?

Increases cell membrane permeability, affecting ion balance

Ectocarpus life cycle pattern

isomorphic (the same)

laminaria life cycle

heteromorphic (different)

What is any way that a population of brown algae can make sure that male and female gametes get released at the same time, so that they have a chance of finding each other?

Eggs get released about 30 minutes after dark, and hormones get released at the same time signaling to release the male gametes as well.                                         

what is this, where is it found, what is it used for

fucus. common in intertidal rocky areas (intertidal zone). used for fertilizer

Spore

reproductive elements (asexual and sexual both), usually dispersed into the environment

hypha (plural: hyphae)

root like structures, fundamental structural unit of most multicellular fungi, essential for nutrient absorption but can be used to reproduce when tips meet

mycelium (plural: mycelia)

network of hyphae

chitin 

a polysaccharide that is the primary structural component of fungal cell walls. provides structural integrity and protection.

Saprotroph

An organism that obtains nutrients by decomposing dead or decaying organic matter. Many fungi are essential saprotrophs, playing a critical role in nutrient cycling in ecosystems by breaking down complex organic materials like wood and leaf litter, which releases essential elements back into the environment.

Parasite

An organism that lives on or in a living host organism, obtaining nutrients from the host and causing harm. Many fungi are plant pathogens, and some can cause infections in animals and humans.

Pathogen

A specific type of parasite that causes disease. A large number of fungal species are plant pathogens, responsible for a majority of plant diseases.

Predator

Some specialized fungi act as predators and capture specific worms to obtain nitrogen.

Symbiosis

A close and long-term biological interaction between two different biological species. Fungi engage in various symbiotic relationships, including mutualism and parasitism.

Mutualism

A type of symbiosis where both involved species benefit from the interaction. A prominent example is the relationship between mycorrhizal fungi and plants.

Mycorrhizae

A mutualistic symbiotic association between a fungus and the roots of a plant. The fungus colonizes the plant roots with its hyphae, helping the plant absorb water and nutrients (especially phosphorus) from the soil in exchange for sugars (carbohydrates) produced by the plant through photosynthesis.

Conidia

asexual non-motile spores on specialized hyphae

Ascospore

a sexual spore typically produced inside a sac-like cell called an ascus, which is a characteristic feature of fungi in the phylum Ascomycota.

Basidiospore

A sexual spore produced on a basidium (most mushrooms)

“fruiting body”

A spore-producing structure formed from a mass of interwoven hyphae. The most familiar example is the mushroom, which is the reproductive part of the fungus, with the vast majority of the organism (the mycelium) remaining hidden in the substrate.

Schlerotia

A compact, hard mass of dormant mycelium that contains food reserves.

how does a fungus grow?

by spreading tiny spores, which land in a suitable environment and germinate into a network of thread-like filaments called hyphae. These hyphae then release enzymes to digest organic matter and absorb nutrients, growing and branching to form a larger, tangled mass called a mycelium, which is the main body of the fungus. Growth is an active process that occurs at the tip of the hyphae, which extend and branch to explore the environment.  

how a fungus obtains and digests food

they secrete enzymes onto their food source, which break down complex organic matter into simple molecules. These molecules are then absorbed directly through the fungal cell walls, as fungi lack a digestive system and must digest food externally before absorption. 

why do some kinds of fungus product antibiotics

as a defense mechanism to protect themselves from competing microorganisms (bacteria and other fungi)

what are the range of substances that fungi attack and digest? is anything safe?

Fungi can attack and digest an extremely wide range of organic substances, including tough materials like wood (lignin and cellulose), animal matter, and even certain man-made pollutants and plastics. While their primary role is decomposing organic matter, virtually nothing organic is entirely safe under the right conditions. 

how fungi reproduce and what structures are involved

Fungi reproduce both asexually and sexually, typically using spores produced in specialized structures like sporangia or conidia, or by fragmentation or budding. Asexual reproduction involves one parent producing genetically identical offspring through structures like hyphae that break apart or yeast cells that bud. Sexual reproduction involves the fusion of two different mating types.

In sexual reproduction, what are the advantages of breeding with oneself (inbreeding) vs. outcrossing? 

Easy to find partner when inbreeding but outcrossing provides increased genetic variation

What is a fairy ring and why does it form?

a circle or arc of mushrooms, dark green grass, or dead grass caused by a single, underground fungal organism called a mycelium

How big can fungi grow?  What is the biggest on record? 

35 acres in Michigan

Mushrooms and other members of the Basidiomycota have basidiospores.  How do those basidiospores get released from their little pedestals, and 

When they have matured they simply fall free and get pushed into the spaces between gills; air currents blow them out

what prevents them from getting stuck between the gills of a mushroom?

By the gills being evenly apart and verticle

Also, if a mushroom or bracket gets bent, what does it do to get the gills or tubes facing down again?

They will reorientate their gills to remain verticle, and the cells will grow rapidly to even out again.

How, when, and why does a schlerotium form?

When temperature or water are not ideal, hyphae will cluster and form a spherical body (the schlerotium), using the outer cells to as a layer of protection for the inner cells.

On what basis are fungi classified, and why is this a problem in the case of fungi like Penicillium?  How can we resolve the problem and decide which phylum Penicillium is in?

Based on sexual reproduction and morphology. Problem with penicillium we are unable to observe a sexual stage. We can use DNA sequencing instead.

What are the three parts of a scientific name? 

genus, species, author

Why is the last part (the author’s name) important? 

to resolve confusion in case a species has been named twice or in case the same scientific name has been given to two different species by two different people

How do rusts and ergots get dispersed?

wind, rain, insects, human activities

How do bird’s nest fungus spores get dispersed?

Rain droplets hit the fungus cup and carry the spores ou

How do shotgun fungus and artillery fungus disperse their spores, and how far can they go in each case?

forcibly ejecting them from cup-shaped structures when they fill with water and burst. The spores can be launched vertically up to 6 feet and horizontally over 20 feet

Ideally, what happens to the shotgun fungus spores after they fall?

Ideally, shotgun fungus spores fall into a suitable organic substrate, like mulch, where they can germinate and form new colonies

.Many fungal spores are distributed by wind.  How far can the spores go, and what is the evidence for this? 

up to 2k km. from sahara dessert to eastern US (keep seeing it in these new areas)