Smith Biology Sections 19.1-19.4

Single-celled: euglenoid Colonial: Volvox Multicellular: green algae

Give an example of each of the following: a single-celled, a colonial, and a multicellular plantlike protist.

1. It is a kingdom for all the eukaryotes that don't seem to fit the animal, plant, or fungi definitions. 2. Some protists are more closely related to other kingdoms than to members of their own kingdom.

Give two reasons why protists are difficult to classify.

It likely belongs in phylum Bacillariophyta (common name is diatoms).

If a multicellular organism contains chlorophyll but no silica, to which phylum does it likely belong?

They both attach to the cell surface. However, cilia are shorter than flagella and more numerous.

In what ways are cilia and flagella similar? How are they different?

They are mostly decomposers.

In what ways are slime molds and water molds similar to fungi?

They are all funguslike protests. They are mostly all decomposers. Both of the slime molds have a process they use when food is scarce.

Make a three-column chart comparing plasmodial slime molds, cellular slime molds, and water molds.

Like animals, this group can move around easily.

Many biologists argue that the euglenoids should be classified as an animal-like protist rather than a plantlike protist. Explain.

Sexual reproduction leads to genetic diversity, which leads to higher chances of survival.

Many plantlike protists, or algae, reproduce sexually when conditions are harsh. Why might this be beneficial?

slime mold

Slime molds are eukaryotic organisms that have both fungus-like and animal-like traits.

The formation of pseudopod formation uses energy.

Why do amoebas form pseudopods only when they need them?

Slime molds are living organisms and need water. Also, they can move easily.

Why doesn't spraying water on slime molds work to destroy them?

cilia

_______are short, hairlike structures that cover some or all of the cell surface and help the organism swim and capture food.

water mold

Water molds are funguslike protists (phylum Oomycota) that are made up of branching strands of cells.

It would be easier to survive because cells could communicate with each other

What might be the advantage of being able to switch from living as separate cells to become a coordinated unit acting like a single organism?

They are both autotrophs and have chloroplast. Some plantlike protists are multicellular also.

What observable traits might green algae and plants share that support the molecular evidence that these two groups are closely related?

protist

A ___________ is a eukaryote that is not an animal, a plant, or a fungus.

pseudopod

A ______________, which means "false foot," is a temporary extension of cytoplasm and plasma membrane that helps protozoa move and feed.

Most protists are single celled like bacteria, but protist are eukaryotic and have membrane bound organelles. Bacteria and archaea are single-celled, but their lack of a nucleus makes them prokaryotic and they lack membrane bound organelles.

At one time, scientists grouped all single-celled organisms together. What are the main differences between single-celled protists and bacteria or archaea?

Plasmodial slime molds absorbs bacteria and nutrients from decaying matter, making at available for other sources.

Describe how slime molds help other organisms within an ecosystem obtain nutrients.

A mosquito bites a human and transmits Plasmodium sporozoites that enter the liver. The parasite develops, leaves the liver, enters red blood cells, and asexually reproduce until the red blood cells burst.

Describe how the parasite Plasmodium causes disease in humans.

Skip the food web. The population of the dinoflagelletes will increase, leading to a shift in population in all species.

Draw a simple food web for a marine ecosystem. Include dinoflagellates, fish and shellfish, diving birds, and humans in your diagram. What might happen if nutrient levels in the water increased?

Flagella are tail-like structures that help unicellular organisms swim. A pseudopod (SOO-duh-pahd), which means "false foot," is a temporary extension of cytoplasm and plasma membrane that helps protozoa move and feed. Cilia are short, hairlike structures that cover some or all of the cell surface and help the organism swim and capture food. Cilia are usually much shorter than flagella and found in much greater numbers.

Name and describe the three basic means of movement used by animal-like protists.

The kingdom Protista includes the animal-like protists, the plantlike protists, and the funguslike protists. The animal-like protists are single-celled heterotrophs. The plantlike protists are photosynthetic and can be unicellular, colonial, or multicellular. Funguslike protists are decomposers and can move during part of their life cycle.

Name the three main groups within the kingdom Protista. What characteristics distinguish each group from the other two?

Animal-like = Heterotrophic Plantlike = Autotrophic Funguslike = Heterotrophic

Organisms that get their food by ingesting it are called heterotrophs, while those that make their own food are called autotrophs. Categorize animal-like, plantlike, and funguslike protists using these two terms.

algae

Photosynthetic plantlike protists are called _______.

Flagella evolved with the eukaryotes.

The flagella of eukaryotes and prokaryotes serve the same function, but they are structurally very different. What does this suggest about the evolution of flagella?

protozoa

The term ____________ is often used informally to describe the many phyla of animal-like protists.