NZ-VR Teacher Resources ENGAGE EDUCATE EMPOWER - PowerPoint Presentation

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NZ-VR Teacher Resources

ENGAGE EDUCATE EMPOWER

FISHING

LESSON 2: NZ Marine Ecosystems – Food Webs

SECONDARY SCHOOL

ExploreYou are about to go on a virtual expedition around four very different marine locations in New ZealandYour task as a virtual marine biologist is to record your observations from each virtual expeditionThese are 360-VR videos: click on the images and then grab to pan on a desktop, or just move a mobile device around you. All devices can be full-screened for the most compelling experience.

Poor Knights Islands

Goat Island

Hauraki Gulf

Three Kings Islands

THREE KINGS

POOR KNIGHTS

HAURAKI GULF

GOAT ISLAND

360-VR Observations

Poor Knights Hauraki Gulf

Goat Island Three Kings

360-VR Observations

Poor Knights Hauraki Gulf

Goat Island Three Kings

Lots of small fish (blue maomao, two-spot demoiselles)

Some big fish (snapper, kingfish)Lots of short-tail sting raysLots of colour and lifeClear water – good visibility Lots of big snapper

Lots of kelpClear water – good visibilityLots of kina (NZ sea urchin)Lots of bare rockJust a few small fish (trevally)

Murky water – poor visibility Lots of kinaSome kelp and seaweedLots of bare rock (with orange sponge)Some small fish (two-spot demoiselles)

(refer to the Species ID resource to identify individual species in each clip)

Kina Barrens

A kina barren in an area of the seafloor which is bare (or barren) rock but with lots of kina

There is hardly any seaweed or kelp and very few fish

Do kina barrens have high or low biodiversity? (recall: biodiversity is the number of different species in a habitat)

Are kina barrens a good or bad thing?

Our goal in this lesson is understand what causes these kina barrensDiscuss

NZ Marine Reserves The Poor Knights and Goat Island are fully protected marine reserves

These “kina barren” sites at the Three Kings and in Hauraki Gulf

are not protected – so why are these sites so different?

Food Chains

To understand the “kina barren” we need to analyse the feeding relationships in a community

A food chain shows how each living organism gets its food The arrows represent the transfer of energy and always point from the organism being eaten to the one that is doing the eatingA food chain starts with the producer (usually a plant) and then shows the consumer (usually a herbivore species) that eats the producer, and then the carnivore species that eats that herbivore species, and so on until you reach the top predator. A top predator is a species that is not eaten by any other species

What food chain is shown in this

video clip?

Food Webs

A food web is a more complex diagram showing all the feeding relationships of living things in a particular habitat

It is made up of many food chains that are interlinked

Food webs are usually organized by trophic level with producers at the bottom or 1

st trophic levelWhy do the trophic levels get smaller near the top?

Food Web Activity #1

In this activity you will build a marine food web:

Cut-out the marine creatures, with their names Use the information provided in the table below to start building a marine food web Space the marine creatures out as much as possible across your deskUse whiteboard pens to draw arrows on your desk (or A3 paper) to show “who eats whom”Where possible, arrange your food web in trophic levels

On your food web, label the producers and herbivores (primary consumers)In your groups, identify a: primary carnivore, secondary consumer, secondary carnivore, tertiary consumer, a species from the fifth trophic levelTake a photo of your completed food web!

Resource adapted from “Canterbury’s Spectacular Coast” (Environment Canterbury)

Food Web Activity #2

Use the

Feeding Behaviour Integrated Literacy Sheets from DOC to build a marine food web which shows the feeding relationship between kelp, kina and snapper

What Might Cause a Kina Barren?

Think:

quietly think about your answer (use your food web and the images below)

Pair: discuss your ideas in pairs with your neighbourShare: be prepared to share your hypothesis with the class

What Causes a Kina Barren?

Watch this

video clip

What Causes a Kina Barren?Kelp is eaten by kina. Kina is eaten by snapper. What happens if lots of snapper are removed from the food chain?What might cause lots of snapper to be removed from the food chain?

Trophic CascadeIf snapper are overfished, kina lose a predator and the population of kina can increase significantly The kina eat more and more kelp forest, until the reef becomes bare rockThe kelp forest no longer provides a habitat for other marine organisms to live, feed and breed in We call this a trophic cascade: a dramatic change in the structure of an ecosystem triggered by the removal of a top predator from a food web

Biodiversity and Marine HealthWhen an area is not overfished (e.g. protected in a marine reserve) snapper are able to control the kina populationThis results in the kelp forest being able to thrive, and improves the health of the ecosystem by providing more food and habitats, supporting higher biodiversityThe presence of large predators is an indicator of a healthy marine environment

Goat Island

In the next lesson:We will use our knowledge of food webs and marine reserves to explore overfishing in NZ coastal waters and what action can be taken to restore and maintain our unique marine environment

Investigate kelp as a habitat. What organisms rely on kelp as a habitat? What is the impact on the marine ecosystem if kelp forests are removed? Consider biotic and abiotic factors such as carbon dioxide.

Extra for experts

Investigate the adaptations of kina. How do they eat? How do kina move? How do they reproduce? How do kina protect themselves from predators? How do snapper and crayfish eat kina? Watch this

clip.