Freshwater Ecology Midterm

What does EPT stand for?

Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies), three orders of benthic insects that are highly intolerant to pollution

A ___ is the fundamental unit of taxonomy

Species

How do older systems of taxonomic classification compare to newer ones?

Older systems classify based on morphological characteristics, while speciation is now done based on genetic comparison

How much variation in DNA base pair sequences is needed to grant separate species status? How much for RNA

30% in DNA, 5% in RNA

Which genes are generally used for identifying both prokaryotic and eukaryotic organisms?

16S rRNA and 18S RNA

How is RNA amplified for microbial diversity measurements?

• Amplification using PCR

• Fingerprinting techniques (Ex. DGGE, T-RFLP)

Define: Lateral gene transfer

The transfer of genes between two organisms by means other than reproduction

Why is ribosomal RNA the best candidate for speciation sequencing?

Because they do not laterally transfer genes

What are the three methods of lateral gene transfer?

• Transduction: Bacteria takes up loose DNA from the environment 

• Transformation: A virus transfers DNA from one bacterium to another

• Conjugation: Two bacteria transfer DNA through contact

Bacteria and Archaea are two groups with maximum ____ diversity, while Eukarya has maximum ____ diversity

Metabolic, morphometric and behavioral

Define: Commensalism

An interaction between two species in which one benefits, and the other is neither harmed nor helped

Define: Ammensalism

An interaction between two species in which one is harmed, and the other is neither harmed nor helped

Most aquatic vertebrates are ____

Bony fishes

How big are viruses?

250 - 350 nm

Viruses have been demonstrated to travel up to ___ deep into groundwater

50m

What are some characteristics of Archaea?

• Single-celled, non-nuclear, and non-organelle organisms 

• Significantly different from bacteria in cell wall structure, and in metabolic processes

• Live in all environments, including hot springs, saline lakes, and anaerobic waters

What is the most diversified organism?

Bacteria

Why are the two types of cells produced by cyanobacteria/blue-green algae

akinetes (resting spores) and heterocysts (site for nitrogen fixation) 

Less than ___ of all bacteria have been identified

1%

What are some characteristics of bacteria

Single-celled, non-nuclear, and non-organelle organisms

What are some characteristics of protists?

• Single celled, heterotrophic organisms (except for protophyta which has chlorophyll)

• Significant members of the nutrient cycle, material degradation, energy transfer, and causing disease

What is Chrysophyceae?

Golden algae (Ex. Dynobryon), considered facultative heterotrophs (shifting between photosynthesis and ingestion)

What is Dinophyceae?

Dinoflagellates , unicellular, freeswimming, has cellulose plates and two flagella, can ingest other organisms or do photosynthesis. Can be toxic

What is Bacillariophycea

• Have a silicate cell wall, called a frustule. Frustrules don't dissolve and get settled in sediments, acting as a proxy to analyze eutrophication history 

• Have elongate, pennate, and circular centric forms 

What is Euglenophyceae?

Euglenids, a group of eukaryotic flagellates, can be pigmented or colourless, autotrophic or heterotrophic, exhibits amoeboid cell movements

What is Chlorophyceae?

A type of green algae, single or multicellular, generally found floating or attached to surfaces

What is Charophyceae?

Stoneworts, considered the evolutionary precursor of most land plants. Can become abundant in productive wetlands, indicative of nutrient pollution

What are some characteristics of Protozoans?

• Can be auto or heterotrophs, small to large

• Can ingest organic particles, viruses, bacteria, and in some cases diatoms 

• Some make cysts, and are highly resistant to environmental extremes 

• Some are parasites to humans, and other organisms such as fish 

• Can be flagellate, ciliate, and amoeboid depending on their mobility

What group of fungi are mostly aquatic?

Oomycota

There are more than ___ species of aquatic fungi

600

Where are aquatic lichens found?

In wetlands, especially boreal and temperate, but never in groundwater

What are the three growth patterns/forms of aquatic lichens?

• Foliose (leaflike)

• Fruticose (finger-like projections)

• Crustose (appressed to solid surfaces)

Plants in water are called ____

Macrophytes

Traditional categories of aquatic vascular plants include

• Floating unattached 

• Floating attached

• Submersed

• Emergent

What are some characteristics of the Phylum Porifera

• Sponges, filter feeders

• Exhibit sexual and asexual (via fragmentation, or production of gemmules) reproduction

• Most are marine, but 35 species are found in freshwater

What are spongillaflies?

Insects that prey on sponges, by piercing the sponge body to feed on its internal fluids

What are some characteristics of the Phylim Cnidaria

• Includes jellyfish, anemones, corals, and hydroids

• Mostly marine (hydrozoans are freshwater)

• Exhibit alternation of generations

What is the most primitive organism?

Sponges

What are the three classes of the Phylum Platyhelminthes?

Turbellaria (free living worms)

Trematoda (flukes)

Cestoda (tapeworms)

Schistosomiasis is caused by __

Shistoma, a type of fluke which needs both humans and snails to complete its life cycle

What are some characteristics of the Phylum Gastrotricha?

• Also called hairy-back worms, microscopic & ciliated

• Abundant in freshwater, but not well studied

• Eggs can survive extreme conditions (freezing, heat, anoxic environments, drying, etc) and be viable for years

What organisms belong to the Phylum Nemertea?

Ribbon worms

What are some characteristics of the Phylum Rotifera?

• 2000 species in freshwater and more in marine

• Produces eggs capable of withstanding harsh conditions

• Includes Bdelloids, the largest metazoan without sexual reproduction

What are some characteristics of the Phylum Nematoda?

• Non-segmented worms living in benthic habitats

• Feeds on detritus, algae, and parts of organic plants

• Includes 2000 reported freshwater species

What organisms belong to the Phylum Nematomorpha?

Horsehair/Gordian worms

What are some characteristics of the Phylum Mollusca?

• One of the most abundant freshwater invertebrates

• Includes several invasive species (Ex. zebra and quagga mussels)

• Bodies have both hard and soft components

What are some characteristics of unionoid mussels?

The most diverse freshwater bivalves found in North America 

Used to make buttons 

Long lifespan: 6-100 years

Where are zebra mussels native to?

The Caspian Sea

How was the zebra mussel introduced into North America?

Via ballast water in the 1980s

What are some characteristics of the Phylum Anellida?

• Includes segmented worms, with tubular bodies and complete digestive tract

• Sexual and asexual reproduction, includes some hermaphrodites (Ex. earthworms)

What organisms belong to the Phylum Bryozoa?

• Simple, sessile invertebrates living in colonies

• Can be encrusted or stalked

What are water bears?

Microscopic, bilaterally symmetrical organisms, that reproduce via parthenogenesis

What are the three main phyla within the group Arthropoda?

• Chelicerata (water mites and spiders)

• Crustacea (Crayfish, shrimp, amphipods, and isopods

• Unirama (insects and collembola)

What is the most diverse & successful group of organisms?

Arthropoda

What is the most primitive form of fish?

Lampreys

What is the difference between anadromous and catadromous?

• Anadromous (born in freshwater): Adults move from saltwater to freshwater to spawn (Ex. Salmon)

• Catadromous (born in saltwater): Adults move from freshwater to seawater to spawn (Ex. Eels)

What are some examples of tetrapods?

Amphibians, reptiles, birds, and mammals

Define: Species diversity

A measure of the number of species present in an area (richness) and how evenly members are distributed within the habitat (evenness)

What is the most common diversity index?

The Shannon Index

North America’s freshwater habitats are divided into ____ ecoregions

76

The ultimate source of biological diversity is ____

Evolution

____ is the most studied ancient lake

Lake Baikal in Russia

What are Hypogean fauna? Why do they have so many unique endemic organisms?

Interior fauna of soils, which have many endemic organisms because there is such a low chance of disturbance

What kinds of habitats usually favour high numbers of endemic species?

Ancient lakes, isolated ponds, river basins with continuous existence, groundwater aquifers with large channels, hypogean environments

What factors influence the distribution of species?

Species interactions and introductions, productivity, habitat type, dispersal ability, and colonization

What is the formula of the species - area relationship

S = cA^z

Where S - # of species, A - area, c - constant (number of species / unit area), and z = slope

Define: Succession

Sequential changes of species dynamics until reaching a climax community 

Define: Minimum viable population

The lowest number of individuals required for a population to survive in the wild 

What phyla is faces the largest threat of extinction in recent times?

Amphibians

What is the formula for the Shannon diversity index?

Define: Continental water systems

Water bodies contained within continents, as opposed to oceanic systems which separate continents

What are some ways in which continental water systems can be formed

Topographic depressions, runoff and run-in, rain, volcanic eruptions leaving craters, etc.

Define: Limnology

The study of continental waters

Why do volcanic crater lakes have acidic conditions?

Due to the deposition of volcanic gases

What did Dr. Evelyn Hutchison do for modern day limnology?

Wrote A Tretise on Limnology, a comprehensive guide to studying inland waters

What are the three major compartments of water in the hydrologic cycle?

Oceanic, atmospheric, and land systems

Define: Fluxes

The movement of water along different compartments

The global renewable supply of water is about , ___ humans use __ of accessible runoff

39 000 km^3 / year, 54%

What is the largest freshwater aquifer in NA?

The Ogallala aquifer

What sector uses the most water in Canada?

Industrial (91.7%), specifically electric power (70% of that)

How much water does Canada use per year (in cubic M)

36.1 billion cubic m

What are the two groups of properties that make water what it is?

• Physical: Dictates how water acts as a solvent, and how density varies

• Chemical: Composition of the water molecule allows it to stay water in a wide range of temperatures. 

What kinds of bonds are present in water molecules?

Covalent bonds, hydrogen bonds

The maximum density of water occurs at __

4 degrees c

With increasing depth and pressure of water, ___ increases

Solubility

What are some of the properties of water?

High heat capacity, boiling and melting points, high surface tension, high heat of vapourisation, excellent solvent for ions and polar molecules

Define: Viscosity

Fluidity, resistance to change from one form to another

Define: Inertia

Resistance to a change in state of motion

What is the purpose of Reynold’s number?

Helps quantify spatial and velocity-related effects on viscosity and inertia, helps understand the effects of water and its movement on living organisms 

What is the formula for Reynold’s number?

Re = Fi / Fv (Fi = inertial force, Fv = viscous force)

Chemical diffusion is affected by:

Concentration gradients, advective transport, temperature, nature and size of molecules, interference by living organisms, etc. 

____ surface area leads to more diffusion

Higher

Diffusion of materials in water is described by ___ law

Fick’s law: Diffusion flux is +vely related to the diffusion coefficient, the concentration gradient, and the reciprocal distance between the source and location at which diffusion occurs 

Light transparency of water bodies can be measured by a ____

Secchi disk

Define: Hydrodynamics

Temporal and spatial movement and distribution of water in the environment

Define: Physiography

Physical geography

Define: Ecohydrology

Hydrology in relation to ecology

What are the two types of scale to consider when studying an organism?

Temporal and distance (Ex. how often does the organism reproduce, what is its lifespan, how big is it, how big is its habitat)

What is the difference between infiltration and percolation?

Infiltration occurs near the surface, percolation occurs underground

When the quantity of water exceeds the ____ (beyond soil saturation) water runs off

matric potential