Marine Mammals Honor

Nature Study

Requirements

1. Mention at least 3 orders of marine mammals, giving examples of each one.

   Answer: Cetacea: whales, dolphins, porpoises (fully aquatic). Sirenia: manatees, dugongs (aquatic herbivores). Pinnipedia: seals, sea lions, walruses (semi-aquatic, they come ashore). Some classifications include aquatic Carnivora: sea otters, polar bears (partly aquatic habits). An impressive evolutionary diversity of adaptation to the marine environment. — Cetacea: 90+ species, a monophyletic group. Suborders Mysticeti (baleen whales) and Odontoceti (toothed whales). Sirenia: 4 living species, relatives of elephants. Pinnipedia: 33 species. Aquatic Carnivora: otters, polar bear. Adaptations: flippers, insulating blubber, blowholes, a diving system. Brazil: common dolphins, humpback whales (Abrolhos), manatee (the North). Adventism: the diverse creation of the 5th day.

2. Cite some characteristics that distinguish marine mammals from the other traditional mammals we know.

   Answer: A hydrodynamic body (torpedo-shaped), flippers (modified limbs), a thick layer of fat (blubber, for thermal insulation), blowholes for breathing (cetaceans), the ability to dive for long periods (up to 2 h), eyes adapted for underwater vision, and echolocation (in odontocetes). They retain lung breathing and nursing. — Hydrodynamics: reduced drag. Flippers: adapted limbs; the tail in cetaceans is horizontal (mammals) vs. vertical in fish. Blubber: 5-50 cm, it insulates and stores energy. Blowhole: nostrils on top of the head. Diving: oxygen in myoglobin, low heart rate. Echolocation in dolphins as in bats. Adventism: a design adapted to the environment, a varied creation. They remain mammals: nursing, warm-blooded.

3. Identify, through photographs or drawings, at least 3 of the following marine mammals, including their location (the region where they live) and the scientific name of each animal:
   • Whale
   • Dolphin
   • Seal
   • Manatee

   Answer: 1) Whale: the humpback whale (Megaptera novaeangliae) is seen along the Brazilian coast, especially at the Abrolhos Bank (southern Bahia), where it breeds between July and November; it is distributed throughout all the oceans. 2) Dolphin: the bottlenose dolphin (Tursiops truncatus) lives in coastal and oceanic waters of tropical and temperate regions worldwide, including all along the Brazilian coast. 3) Seal: the harbor seal (Phoca vitulina) inhabits cold waters of the Northern Hemisphere (the North Atlantic and North Pacific); in Brazil, the South American fur seal (Arctocephalus australis) occasionally appears, coming from the south, along the coast of the South and Southeast regions. 4) Manatee: the West Indian manatee (Trichechus manatus) lives in shallow waters, estuaries, and mangroves of the North and Northeast coast of Brazil (from Amapá to Alagoas/Espírito Santo). — Bottlenose dolphin: common, intelligent, in interactions with humans (Pororó/PR-RJ). Humpback whale: see its acrobatics at Abrolhos (Jul-Oct). Manatee: threatened, a slow herbivore, in rivers of the North. Others: orca, blue whale, gray seal. Identification: flipper, fin, color pattern. Brazil has 50+ species of cetaceans. Adventism: care for threatened creation (Ps 24:1).

4. What is the largest mammal in the sea? Describe its natural characteristics according to the following terms:
   • Where it is located
   • Measurement and Weight
   • Diet

   Answer: The largest mammal in the sea (and the largest animal that has ever existed) is the blue whale (Balaenoptera musculus). 1) Where it is found: it lives in all the oceans of the planet, making long migrations between cold feeding areas (closer to the poles) and the warmer waters where it breeds. 2) Size and weight: it reaches about 30 m in length and can weigh from 150 to 200 tons; the heart weighs about 180 kg (the size of a small car) and the tongue can reach 2.7 tons; the calf is born about 7 m long and gains around 90 kg per day. 3) Feeding: it feeds mainly on krill (small crustaceans), consuming up to about 3.6 tons per day, which it filters from the water through the baleen (bristles) in its mouth. — Cetacea, Mysticeti, Balaenopteridae. Heart the size of a small car. Krill: small crustaceans filtered by the baleen. Research: whaling reduced their numbers drastically; currently 10,000-25,000 individuals. Southern Hemisphere (Antarctica): the largest. Migrates to breed in tropical waters. Sound: communication over hundreds of km. Adventism: its impressive size shows the greatness of the Creator (Ps 104:25-26).

5. Explain the following expressions:
   • Breach (jump)
   • Echolocation
   • School (of fish)
   • Fins
   • Harem
   • Plankton

   Answer: 1) Breaching: this is when the whale or dolphin propels its body out of the water and falls back; it serves for communication, play, removing parasites from the skin, or simply for moving about. 2) Echolocation: this is the ability to locate objects, prey, and obstacles by emitting sounds (clicks) and listening to the echo that returns when they bounce off them; dolphins and toothed whales use this to orient themselves and hunt in dark waters. 3) School (shoal): this is a large group of fish swimming together in the same direction; many marine mammals feed on these schools. 4) Fins/flippers: these are the fins of aquatic animals, used to swim, change direction, and keep balance; in whales, the term 'baleen' is also used for the bristles in the mouth that filter food. 5) Harem: this is the group formed by a dominant male and several females with whom he breeds; it occurs in some pinnipeds, such as sea lions and elephant seals. 6) Plankton: this is the set of microscopic organisms (algae and small animals, such as krill) that float in the water and serve as the base of the diet of many marine animals, including the great whales. — Cetacea: the monophyletic group of whales. Pinnipedia: close relatives of bears. Blubber: 5-50 cm of subcutaneous fat. Blowhole: the nostrils migrated during evolution to the top. Echolocation: reflected clicks form a 3D image. Migration: feeding vs. breeding. Stranding: due to disorientation or disease. Adventism: a varied and differentiated creation for each ecological niche in the ocean throughout the world.

6. Draw the food chain of 2 different marine mammals of your choice.

   Answer: Blue whale: phytoplankton → krill → blue whale (2 levels). Dolphin: phytoplankton → zooplankton → small fish → medium fish → dolphin (5 levels). Draw arrows indicating 'is eaten by'. Include producers (algae), primary consumers (zooplankton), secondary consumers (fish), tertiary consumers (mammals), decomposers (bacteria). — Food chain = energy flow. Photosynthetic producers (phytoplankton) at the base. Each trophic level transfers ~10% of the energy. Top predators (an orca can eat a young whale). Decomposers: bacteria and bottom-dwelling crustaceans. Diagrams: directional arrows. Draw with colors to identify the levels. Adventism: an interdependent creation, the ecological balance of the ocean (Ps 104:25).

7. What is the main importance of blubber for cetaceans?

   Answer: Blubber (fat) has multiple functions: thermal insulation (it keeps body temperature stable in cold waters of 4-37°C), an energy reserve (during long migrations without feeding), buoyancy (fat is less dense than water), protection against impacts, help with hydrodynamics, and it stores fat-soluble vitamins. It is crucial for aquatic survival. — Thickness: 5-50 cm depending on the species. The bowhead whale has the most blubber. Density: 0.9 g/cm³ (water: 1). Energy: 9 kcal/g. Thermoregulation: cold skin, warm core. Migrations: up to 6 months without eating. Vitamins A, D, E are stored. In tropical waters, less blubber. Adventism: the precise design of creation for different ocean environments of the world.

8. Know 2 reasons why seals are still hunted.

   Answer: Hunted for: skin (valuable luxury furs), fat (seal oil, omega-3 supplements), meat (food in traditional cultures such as the Inuit, Greenland), indigenous cultural tradition. Large-scale commercial hunting has been banned in many countries, but it traditionally continues on a small scale in native communities. — Skin: white pup fur (historically the most expensive). Oil: rich in omega-3 (cosmetics, supplements). Meat: part of the traditional Arctic diet. Inuit: regulated hunting for subsistence. Commercial: Canada has a quota. Greenpeace and NGOs fought against mass hunting (1980s). It is currently banned in the EU. Adventism: care for creation and respect for native culture when it is sustainable.

9. Explain why seals and dolphins move so quickly in the water.

   Answer: A hydrodynamic body (a torpedo shape reduces drag), smooth skin without long hairs, powerful flippers/fins (the tail in dolphins, the hind flippers in seals), strong musculature, subcutaneous fat that adjusts density, and an efficient cardiovascular system to supply oxygen. The combination of adaptations allows speeds of 30-65 km/h. — Hydrodynamics: the shape avoids turbulence. Smooth skin: a microscopic ridged structure (dolphin) reduces drag. The dolphin's tail: vertical oscillation, propulsive force. Seal: hind flippers alternating. Muscles: fast contraction, dense myoglobin. Heart: 200 bpm while diving, 4 bpm at rest (seal). Adventism: a perfect biomechanical design for the aquatic environment created by God.

10. Choose one of the following tasks:
    • Visit an aquarium in your region. Observe and describe the daily feeding of one of the marine mammals present at that location.
    • Write a report of at least 500 words about a marine mammal of your choice.

    Answer: Visit an oceanarium, aquarium, or marine museum. Watch a documentary about cetaceans (BBC, National Geographic). Write a report with photos. Symbolically adopt a whale or dolphin through an NGO. Volunteer in marine protection projects. Give a talk to the unit. Document each activity for the instructor to evaluate. — Aquariums in Brazil: AquaRio, AcquaMundo, Beto Carrero. Museums: MAR (RJ), Oceanográfico (USP). Documentaries: BBC's 'Blue Planet', 'Encountering whales'. NGOs: Instituto Baleia Jubarte (BA), Projeto Toninhas. Volunteering: sighting records. Talk: present with slides to the unit. Adventism: environmental education values the divine creation and teaches responsible care.