Ameboid Protists

Question 1

Terrestrial Protists

Answer 1

**These are ameboid protists: terrestrial Amoebozoa, commonly found in forests, fields, and wetlands of Ohio(and elsewhere of course)

Two main types are Plasmodial Slime molds and Cellular Slime Molds

Question 2

Plasmodial Slime Molds

Answer 2

HUGE, UNICELLULAR AMEBOID organism; Essentially individual cells/spores join/fuse together and form unicellular, multinucleate organism(many nuclei from individuals cells within one unicellular organism); Being unicellular allows for coordinated movement, feeding and reproduction

Question 3

Cytoplasmic Streaming

Answer 3

used by plasmodial slime molds for movement of cytoplasm around cell, just like aquatic amoebas

Question 4

How do plasmodial slime molds retrieve energy?

Answer 4

Being Chemoheterotrophs: important decomposers in terrestrial food webs, breaking down organic matter for energy and carbon

they are more specifically osmotrophs, using external digestion(Releasing enzymes to break down organic matter, absorbing products of digestion(carbon/nutrients) for distribution around organism )

Question 5

Reproduction in Plasmodial Slime Molds

Answer 5

Often driven by environmental stress(Drought, temperature changes, etc.)

Use spore producing Sporangia( that vary in shape and color from species to species); Once mature, sporangia burst, spreading spores to environment(Spores remain dormant until conditions are right (air temp, moisture levels) for growth)

Once they start to grow, they are mobile (moving) amoeboid form that can sense food and move towards it and begin to feed(receptors on their cells and pick up biological cues in relation to food to feed through osmotrophy) and grow; Feed through osmotrophy and grow through process

Question 6

Human Work with Slime Plasmodial Slime Molds

Answer 6

• can spread outward to find food, organizing itself in the most efficient way possible to get food to whole body; can learn good food choices, avoid toxins
• Used in transportation research: research looked at how well PSM could replicate Japanese rail System (Shinkansen rail system); In study, researchers places pieces of oatmeal (food source) where each city on the train rout was and placed the PSM in Tokyo; Over time, pulling cytoplasm into web like structure to meet all oatmeal pieces; connected the dots; tissues to just connect dots across oatmeal in efficient way like human railway system does

Question 7

Cellular Slime Molds

Answer 7

Similar to Plasmodial slime molds, BUT NOT ONE LARGE UNICELLULAR ORGANISM; INDIVIDUAL, mobile, ameboid cells move around independently; Great ability to find food sources;Chemoorganoheterotrophs(osmotrophs)

Question 8

Reproduction in Cellular Slime Molds

Answer 8

Triggered by environmental stress (changes in moisture and temperature); Individual ameboid cells come together to form a multicellular colony (“slug” stage, Like stranger things monster, ew)

Aggregate, form large, tall structure, then becomes slug/ooze stuff; Then looks for right conditions for reproduction to create Sporangiophore

Question 9

Sporangiophore

Answer 9

made up of individual cells that form DIFFERENT PARTS of this structure (to release more spores to environment)

Question 10

Use of cellular slime molds in studies

Answer 10

Used to study social behavior and how multicellular organisms may have evolved; Significant

Question 11

Aquatic Amebozoa

Answer 11

While slime molds are terrestrial ameobozoa, most ameboid organisms are AQUATIC(free-living and shelled forms); Free-living Aquatic Ameobozoa

All are unicellular chemoorganoheterotrophs (use dead/living organic matter for energy and carbon); All have pseudopodia used for multiple purposes

Question 12

Pseudopodia

Answer 12

false feet, can form anywhere along cell membrane, Possible because amoeba control cytoplasm movement around cell; Used for Locomotion(movement by extending pseudopodia); Used for feeding through Phagocytosis

Question 13

Phagocytosis

Answer 13

engulfing prey/food

Essentially, use pseudopodia to capture and trap prey/food; Prey are trapped in food vacuole pinched off from cell membrane; Enzymes flood into food vacuole and digest prey/food; Products of digestion pass across vacuole membrane into cytoplasm for energy, carbon, nutrients for use in growth and reproduction

Question 14

Role of Aquatic Amoebozoa in food web and world

Answer 14

• very diverse

As seen in preceding slides, PRIMARILY PREDATORS (feeding on
living organisms; +,- interactions…one organism benefits, other dies)

can also be DECOMPOSERS, feeding on dead organic matter (still
using phagocytosis)

others are PATHOGENS (disease-causing) or PARASITES (+,-
interactions, one organism benefits, the other dies or is harmed)

Question 15

Aquatic Amoebozoa Entamoeba histolytica

Answer 15

amebic dysentery, Parasitic protist that is major problem in developing countries, areas with poor water treatment capabilities

Can be infectious as free-living organism or cysts(resting stages); People become dehydrated, which can lead to organ breakdown(but rarely fatal); treatable but not pleasant

Question 16

Aquatic Amoebozoa Naegleria fowleri

Answer 16

Very rare, BUT DEADLY(only a few people survive); Occurs when person breaths in contaminated warm freshwater through their nose; Organism gets into brain, causes infection; One reaching brain, very difficult or impossible to treat

Question 17

Shelled Marine Ameboid protists

Answer 17

Unicellular amoeboid organism that secrete shells around themselves; two types are radiolarians and foraminifera

Radiolarians and Foraminifera form
limestone deposits when they die (their shells settle on bottom of ocean);
can be used to reconstruct past climates
based upon what species are present (each species has specific climatic & water quality requirements and tolerances); Found in ancient sediment, recording the temperatures and ice sheets found on earth at that time

Question 18

Radiolarians

Answer 18

silica based shell, produce remarkably
complex crystalline structures

Question 19

Foraminiferia

Answer 19

Calcium based shell, Incredible species diversity, complex shells