Questions from SI Exam 2 Review Session

Protists

1. True or False? Protists are eukaryotes.

True

2. Malaria is one of the most dangerous infectious diseases on a global scale. What is it caused by?

Parasitic protists Plasmodium – blood flow is restricted and RBC’s cannot get oxygen to every organ

3. What is the mechanism of infection for malaria?

Anopheles mosquito bite

4. Can you think of a few factors that contribute to the presence of malaria?

High human population densities (more hosts = more parasites), poorer nations not having access to antimalarial drugs or other preventative measures (mosquito nets), and increasing drug-resistance in Plasmodium, insecticide – resistance in mosquitoes (an example of evolution by natural selection.)

5. What was the Irish Potato Famine caused by? a. Virus b. Prion c. Prokaryoted. Protist

6. Can you think of a few factors that contributed to the Irish Potato Famine?

Overreliance on one crop, low genetic diversity in potato population, and social causes.

7. Why must the diatom in this diagram switch from asexual reproduction (mitosis) to

sexual reproduction (meiosis?)

The smaller diatoms cannot divide anymore, so then carry on to produce sperm and egg, fertilize, develop zygote, and grow a mature cell.

8. Does mitosis occur in asexual or sexual reproduction? What about meiosis?

Mitosis – asexual Meiosis – sexual

9. What is true about a protist’s life cycle? a. Their life cycle can include both asexual and sexual reproductionb. Only sexual reproduction is used by a protist c. Protists only use meiosis d. Protists can only perform mitosis

10. Why are protists so important?

Ancestors of plants, fungi, and animals. They are abundant in aquatic ecosystems, autotrophic protists (algae) produce oxygen by photosynthesis, provides habitat for small fish, some protists are decomposers that are important in energy and nutrient flow pathways as well as being consumers (also important in energy and nutrient flow.)

11. There are different feeding strategies of predacious protists. Can you name them and how they work?

Pseudopodia engulf food and cilia sweep food into mouth.

12. Protists are motile which enables them to seek out food and other resources. What are 3 mechanisms they use to move?

Flagella, cilia, and pseudopodia

13. Why would a protist need to utilize both asexual reproduction and sexual reproduction within their life cycle?

To cope with environmental stress or low population numbers.

14. What trophic level do autotrophic protists (algae) belong to?

Primary producers

15. What are some characteristics of protists?

- Eukaryotic - Occur as unicellular or colonies - Simple body plan - Can be heterotrophic or autotrophic (algae) - Autotrophic protists have chloroplasts (unlike autotrophic prokaryotes that

have only chlorophyll.) - They are motile – flagella, cilia, and pseudopodia - Aerobic cellular respiration produces ATP - Reproduce asexually by mitosis and sexually by meiosis..

Intro to Animals

1. What are three characteristics of an animal?

Eukaryotic, multicellular, no cell wall

2. T or F? An animals body plan can range from small (few cell types; sponges) to large (tissues and organs; veterbrates.)

True

3. T or F? Animals are autotrophs.

False

4. What are three different types of skeletal systems of animals?

Hydrostatic skeleton – fluid-filled tissue under compression (soft-bodied invertebrates) Exoskeleton – rigid structures on outside of body (arthropods)

Endoskeleton – rigid structures on inside of body (vertebrates)

5. What is the meaning of cephalization?

The concentration of organs and nervous control at the anterior end of an organism, developing a head and brain. Occurs during embryonic development.

6. T or F? All animals (except sponges) have neurons and muscle cells.

True

7. Which of the following lists of traits accurately describes the correct sequence of events of evolution, beginning with the first (earliest or oldest) trait to emerge, and ending with the most recent trait to emerge? a. Body segmentation, diploblast embryo, triploblast embryo, multicellularity,

specialized cells, cephalization b. Multicellularity, specialized cells, diploblast embryo, triploblast embryo,

cephalization, body segmentationc. Diploblast embryo, specialized cell, triploblast embryo, cephalization, body

segmentation, multicellularityd. Triploblast embryo, multicellularity, cephalization, diploblast embryo, body

segmentation, specialized cells

8. What organism is it believed that animal origins descended from? a. Bacteriab. Protistsc. Monkeyd. Fungi

9. What is the oldest animal lineage? a. Porifera (sponges) *** Origins of specialized cell typesb. Cnidaria (jellyfish, corals, sea anemones) c. Platyhelminthes (flatworms)d. Mollusca (snails, clams, squid)

10. What is the difference between a diploblast embryo and a triploblast embryo?

Diploblast has 2 germ layers (ectoderm, endoderm) while a triploblast has 3 (ectoderm, mesoderm, endoderm)

11. Make a list of what each of the germ layers give rise to. What is derived from them?

Ectoderm – skin and nervous system derived from ectoderm Mesoderm – both muscle and bone is derived from mesodermEndoderm – digestive tract and associated organs derived from endoderm

12. What are some examples of lineages that are triploblastic animals?

Mollusca, Annelida, Arthropoda, Vertebrata

13. T or F? Body plans of triploblast lineages (bilateral symmetry, cephalization) enable greater central nervous system complexity?

True

14. What enabled the Cambrian explosion in species diversity?

Origin of body segmentation (Annelida, Arthropoda, Vertebrata)

15. Which of the following trophic levels (feeding groups) do animals occupy within food chains? a. Decomposer b. Primary consumer c. Secondary consumer d. All of the above

16. What is the definition of a “keystone species?”

A species that greatly affects community structure (species composition and diversity, population sizes.

17. What is an “ecosystem engineer?”

An organism that creates habitat. Ex: corals

18. Give four reasons why animal are important to human welfare.

Humans depend on animals for food, medical science (painkiller derived from toxin of tropical cone snail), animals maintain ecosystem services (plant pollination), animals adversely affect human health (and economies) (rodents harbor human pathogens.)

19. What are some causes of human-induced decline in species diversity?

Habitat loss, pollution, overconsumption of natural resources, and climate change.

20. True or False? Climate change has generally caused declines in coral abundance because coral production declines as the pH of the water declines.

True

Annelida, Mollusca, Flatworms

1. Make a list of annelid characteristics.

Worms with body segments. Oligochaetes (earthworms) – decomposers while leeches are secondary consumers (carnivores, ectoparasites) Hydrostatic skeleton; move by muscle contraction. Has a CNS. Asexual (fragmentation) or sexual (monecious)

2. Give 2 reasons why annelids are important in ecosystems.

Inhabit soil and sediment of many types within aquatic and terrestrial ecosystems. They are detritivores and prey, they are important in energy/nutrient flow pathways.

3. What is the importance of annelids to human welfare?

Ecosystem services – oligochaetes enhance soil fertility by consuming organic matter and excreting nutrients and by increasing soil porosity

4. Make a list of mollusk characteristics.

Body plan – mantle and foot. Primary consumers (herbivores, gastropods, bivalves) secondary consumers (carnivores, cephalopods) Hydrostatic skeleton; move using muscular foot, or jet propulsion or tentacles derived from foot. Asexual (parthogenesis in few species) Sexual (monecious or dioecious) – internal (mostly) or external fertilization; eggs hatch into larvae or juveniles resembling small adults.

5. Give 2 reasons why mollusks are important in ecosystems.

Inhabit many aquatic and terrestrial environments. Important in energy/nutrient flow pathways as primary consumers; gastropods consume plants or benthic algae, bivalves filter-feed on phytoplankton

6. What is the importance of mollusks to human welfare?

Economically important as food and nutrition for us as food. Gastropods are hosts for flatworms ex. Schistosoma that cause human disease.

7. Make a list of Platyhelminthes characteristics.

Body plan – flat (usually non-segmented) worms. Secondary consumers (endoparasites, cestodes, trematodes) decomposers or secondary consumers (carnivores, turbellarians) Hydrostatic skeleton. Asexual- turbellarians (often) by fragmentation. Sexual (monecious or dioecious) – some have complex life cycles (Schistosoma)

8. Give 2 reasons why flatworms are important in ecosystems.

Restricted to aquatic ecosystems or endoparasitic lifestyle. Endoparasitic flatworms can regulate host population sizes.

9. What is the importance of flatworms to human welfare?

Diseases from flatworms effect human health and economies. Cestodes acquired by eating raw or undercooked meat. Schistosomiasis is caused by a trematode.

10. What type of embryos do annelids, mollusks, and flatworms have?

Triploblastic

11. Which of the following are decomposers as well as prey for other animals? (Which makes them very important in the energy and nutrient flow pathways of soil food webs.) A. Trematodes (flukes) B. Oligochaetes C. LeechesD. Cestodes (tapeworms)

12. Review Schistosoma life cycle. How would you accurately describe the life cycle?

Schistosoma eggs hatch into larvae which infect a gastropod. They then undergo metamorphosis into another larval stage and leave the gastropod, penetrate human skin, mature in the human liver and reproduce in the intestine, and produce eggs that are released in human feces.

13. What can humans become infected with from eating undercooked meat?

Cestodes (tapeworms)

14. Recall the frog in the jar that Dr. Stewart showed in lecture. What type of endoparasite caused the hind limb deformities of the frog?

Trematode (fluke)

15. Give an example of an ecosystem service performed by an animal discussed in this lecture?

Oligochaetes increasing soil fertility and plant production by increasing water infiltration and oxygen levels.

16. T or F? The high surface area relative to body volume in flatworms is an adaptation (maximize movement of nutrients and other materials across body wall.)

True

17. Review structure of a tapeworm.

18. Review importance of flatworms in ecosystems (frog deformities.)

19. Review Schistosoma reproduction.

20. Review Schistosoma infecton.

17.

18.

19.

20.

Cnidarians and Sponges

1. Make a list of some characteristics of a sponge.

Few cell types, no tissues or organs, radial symmetry, body composed of pores and channelsFilter feed on phytoplankton and detritus, some have endosymbiotic algae Sessile; hydrostatic skeletonNo CNS (no brain or neurons) Asexual – fragmentation or gemmule (resting stage) productionSexual – monecious

2. What does it mean to be “sessile?”

Fixed in one place; immobile

3. How do sponges obtain energy?

They are primary consumers (phytoplankton) and detritivores (detritus)

4. What is the definition of the term “monecious?”

Individuals possess male and female sex organs

5. How does fertilization occur when a sponge reproduces sexually?

Sperm released in water, fertilization occurs when ingested by another sponge; egg, larva and adult stages

6. T or F? A sponge is radial symmetrical and has no tissues or organs.

True

7. Which of the following statements are correct? a. Both sponges and cnidarians have cells organized into tissue and organ systems b. Both sponges and cnidarians have a hydrostatic skeleton c. Both sponges and cnidarians have a central nervous systemd. All of the above

8. List some characteristics of a cnidarian.

Tissues and organs, radial symmetry, tentacles with cnidocytes, medusa or polyp formsNervous system consists of a “nerve net” (no brain or CNS) Secondary consumers – eat small animals, some with endosymbiotic algae Sessile or planktonic; hydrostatic skeleton Asexual (budding) or sexual (monecious)

9. How do cnidarians reproduce?

Asexual – (primary mechanism during favorable environmental conditions) – budding Sexual (monecious) – complex, involves several life stages

10. Cnidarians obtain their energy.. a. Primarily by consuming detritus b. Primarily by consuming phytoplanktonc. Primarily by consuming small animalsd. Only by photosynthesis

11. What is a cnidocyte?

Injects venom into prey and paralyzes it

12. T or F? Drug candidates for treatment of CNS diseases are derived from cnidocyte toxin?

True