BIOL2204 2021 S2 Practical 1 Workbook solutions PDF

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questions with answers provided to practical 1 workbook....

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School of Biological Sciences Faculty of Science

BIOL2204 Zoology Semester 2, 2021

Practical 1 Workbook Protista, Porifera, Cnidaria, Echinodermata Dr Gurion Ang [email protected] (include ‘BIOL2204 Prac’ in your e-mail subject)

For all practicals:

wear comfortable, covered shoes

(recommended) bring your laptop or other smart devices to access online resources

(recommended) bring your dissection kit and lab coat for practicals that include a dissection activity

participate actively, collaborate with your peers and tutors, and ask questions

Practical 1 Schedule Duration Pre-prac

Main Activity › Watch all pre-prac videos on Learn.UQ › Welcome and Laboratory Safety Induction

20 minutes

› Meet your Tutors › Zoological Mystery 1

30 minutes

› 1.1 Protists

30 minutes

› 1.2 Porifera

30 minutes

› 1.3 Cnidaria

40 minutes

› 1.4 Echinodermata › Conclusion & Quiz Information

20 minutes

› Concise Writing › Inspera Tutorial

Post-prac

› Complete Practical 1 Quiz

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General Introduction to the BIOL2204 practical series Life on Earth has been evolving and adapting for billions of years, resulting in a vast diversity of past and present organisms. Along with this diversity we find many shared features and, using these, we can divide this enormous range into different levels of biological organisation. Organising the diversity of life is a complex and ongoing challenge as researchers identify thousands of additional species each year. Estimates of the total number of species range up to over 100 million. Each species is described and organised according to eight major classifications:

 Hydromys chrysogaster; rakali (water-rat); can be found at UQ Lakes.

Domain

Eukarya

Kingdom

Animalia

Phylum

Chordata

Class

Mammalia

Order

Rodentia

Family

Muridae

Genus

Hydromys

Species

H. chrysogaster

There are three Domains of Life: Bacteria, Archaea, and Eukarya. Within the Eukarya, there are three main kingdoms: Plantae, Fungi, and Animalia. Throughout our practical series we will focus on kingdom Animalia, starting at the most basic of protists (no longer classified as animals) and exploring related groups of gradually increasing anatomical and physiological complexity and evolutionary sophistication. Importantly, we will appreciate the correlation between form and function at all levels of biological organisation. Analysing a biological structure gives us clues about what that structure does and how it works. Conversely, knowing the function of something provides insight into its construction.

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1.1 Protists ‘Protists’ is an informal classification (rather than a recognised phylum) that is paraphyletic. Protists exhibit more structural and functional diversity than any other group of eukaryotes. Zoological Mystery Challenge (revealed during class) In your groups discuss how you would go about addressing the zoological mystery:

4 Key Points need to write in mystery: Metholodology then, key findings (results) conclusion from results (interpretation) Limitations (dont write sample size or human error). look at photo on phone.

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Tip: Use the mark allocation for each question to determine how much to include in your response.

Question 1 Tip: Use the cognitive verb in the question (bold bold ) to determine what you include in your response.

These questions are not assessed.

Characterise Chlamydomonas spp. based on how it derives nutrition. (2 marks)

some are photoautotrophs, some are facultative heterotroph

Question 2 It has been demonstrated that Euglena and Ceratium are mixotrophs. For one of them, explain how structures or features in the slide provide evidence for this form of nutrition. (4 marks)

Mixotroph - organism that is both autotrophic and heterotrophic Osmotroph - absorb soluble food from environment Phagotroph - consume food via phagocytosis Organism Euglena - has flagella allowing it to move suiggesting they are heterotrophic and seek out food, they also have green chlorophyll meaning they are photoautotrophic. Vacules are present indicating they can ingest vid phagocytosis.

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1.2

Porifera

Sponges are multicellular animals that are sessile, drawing food and water into its body via flagellated ‘collar’ cells. Their bodies are designed for highly efficient filtration of suspended particles from the surrounding water, and as such they perform a significant ecosystem service in maintaining water quality.

siliceous spicules (Hexactinellida)

(Demospongiae)

(Demospongiae)

calcareous spicules (Calcarea)

Task Using a compound microscope, view the following slides of sponge structures that are provided to you: •

spicules

•

spongin

Question 3 Spicules are a reliable and recognisable structure typically used to classify sponges to class. (a) Classify to class level the sponge based on the spicules in the slide. (2 marks) Spongin was present, spicuels did not have 6 rays therefore is demospongiae

(b) Describe the main functions of spicules based on their structural integrity. (2 marks) Provide structure to the sponges and provide a physical defence to predation.

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Question 4 Spongin is a type of collagen found only in Demospongiae. Based on the structural features of spongin in the slide, hypothesise its likely function. (1 marks) Provides the matrix that holds the spicules together and provides flexibility etc

Question 5 Suggest why it is problematic using spicules to classify the Homoscleromorpha. (2 marks) No spicules, they have a true epithelium instead

Show and Tell View the specimens of sponges available and discuss with your tutor about body plan, body size and its implications.

Choanacyte - cell with flagella that also uptakes food from water. then push water back out the osculum (top of sponge) Calgeria only sponge to have asconoid body plan Syconoid - cohanocyte in chambers therefore more surface area Leuconoid - Choanocyte in canals therefore even more surface area and helpful for sexual reproduction as less chance of self fertilising.

Tip: Take notes when you have discussions with your tutors. Writing improves metacognition of what you are learning.

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1.3 Cnidaria Task View the following specimens of Class Anthozoa provided to you: •

Aiptasia spp. (live) (Subclass Hexacorallia, Order Actiniaria)

•

Acropora spp. (Subclass Hexacorallia, Order Scleractinia)

•

Fungia spp. (Subclass Hexacorallia, Order Scleractinia)

•

Tubipora spp. (Subclass Octocorallia, Order Alcyonacea)

Question 5

2 basic body forms: pollyp and medsca

Aiptasia spp. are often described as pests in both ornamental and commercial aquaria. It competes with other cnidarians for space, and occasionally kills desirable fish and invertebrates. Given that Aiptasia spp. is predominantly sessile and attached to substratum, describe how it is able to efficiently kill highly mobile prey like fish (pictured). (3 marks)

Nematocyst - has coiles harpoon like thing, is activated by 2 signals; chemical (once chemical signal is detected the trigger is lengthered) from then it relies on a mechanical signal ie fish touching. this releases the nemotacyst harpooning the fish and releasing neurotoxin

Question 6 The preserved specimens still possess intricate and well-preserved structures. Explain why this may be the case. (2 marks)

Calcium carbonate is a complex structure which allows for maximum tissue attachment that is secreted. by both soft and hard corals.

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Task View the following specimens of other cnidarians provided to you: •

Catostylus spp. (Class Scyphozoa) Generic jellyfish

•

Physalia spp. (Class Hydrozoa)

•

Bluebottle - colony of polyps and medusa body forms not one organism. nematophore is one medusa organism that forms the air bubble. Chironex fleckeri (Class Cubozoa) Box jellyfish etc, has ocella sort of like an eye that can sense light.

Question 7 discuss Compare these specimens relative to body form, and di scuss the implications of this on their locomotion. (4 marks)

Question 8 Noting the interesting biology of Physalia in relation to its gas chamber, discuss the implications of this on how jellies can live in anoxia. (1 mark)

Air filed chamber contains oxygen and therefore can draw oxygen from there to survive in anoxic conditions.

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1.4 Echinodermata Recall from lectures An important distinction between echinoderms from other multicellular invertebrates including the sponges, and cnidarians you’ve explored previously is the process of embryonic development. Echinoderms are deuterostomes.

Question 9 If echinoderms are deuterostomes, then protists, sponges and cnidarians must be protostomes. Discuss the validity of the above statement. (4 marks) deuterostome - have radial cleavage, then forms blastapor which becomes the anus. the mouth forms secondarily. Proterstome - spiral cleavage, blastaphore forms the mouth first. gut is space between mouth and anus and celium is space on either side.

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Task View the following specimens of live or preserved echinoderm specimens provided to you: •

sea star (Class Asteroidea)

•

brittle star (Class Ophiuroidea)

•

urchin (Class Echinoidea)

•

sea cucumber (Class Holothuroidea)

•

sea lily (Class Crinoidea)

Question 10 Contrast the tube feet of sea stars and brittle stars to determine their implications on feeding and locomotion. (4 marks) Brittle stars dont need sophisticated tube feet or water vascular system. dont have suckers therefore dont use them for locomition just feeding. sea stars can use tube feet for both moving and passive food to the mouth. both work by changing pressure of water in their arms allowing them to extend or retrace the tubes when needed.

Question 11 An important feature of urchins is the Aristotle’s lantern. Characterise the symmetry and function of this structure. (2 marks) helps it to eat. strong beak that scrapes along the surface. urchin has pentaradial symetry which is defining characteristic of echinoderms. function of lantern is scraping algae of rocks.

have water vas system and tube feet. and spines that move in ball and socket joint. have pedicelleria on most sea stars and urching. the function is biofouling (self cleaning) and also has a function in feeding, etc grabbing food.

Question 12 In sea cucumbers, some tube feet are modified into circumoral tentacles (= around the mouth, pictured). Hypothesise the likely function of these structures. (1 mark)

to get food, covered in mucus to trap particles.also have respiratory tree, breath through anus, dont put condom on sea cucumber anus!!!!

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