Lt 10 PDF - Chordate and Marine Adaptations

Four Key Features of Chordates All chordates have four distinctive structures – A notochord: a stiff flexible rod extending the length of the body – A dorsal, hollow nerve cord: lies above the digestive tract and expands anteriorly to form the brain – Pharyngeal gill slits: locat...

Four Key Features of Chordates All chordates have four distinctive structures – A notochord: a stiff flexible rod extending the length of the body – A dorsal, hollow nerve cord: lies above the digestive tract and expands anteriorly to form the brain – Pharyngeal gill slits: located in the pharynx that may form respiratory organs or may appear as grooves – A post-anal tail: the chordate tail extends past the anus  Notochord The notochord is a flexible, rod-like structure derived from mesoderm. – The first part of the endoskeleton to appear in an embryo. – Place for muscle attachment. – In vertebrates, the notochord is replaced by the vertebrae. Remains of the notochord may persist between the vertebrae.  Tunicate incurrent siphon excurrent siphon (water enters) (water exits) atrial tail mouth opening anus gill slits nerve attachment gill gut cord points slits notochord heart gut gonad larva adult (b) Tunicate https://www.youtube.com/watch?v=yrSUlvzKPMI Hagfishes https://www.britannica.com/animal/reptile/Circulatory-system  Distribution of species on Earth The land has more species because it has greater environmental variability than the ocean Most ocean species are benthic because of greater environmental variability compared to pelagic environments Animal Diversity-4 Prof. Eddie Ma 4 Nov 2024 Adaptations of organisms to the marine environment The marine environment presents many challenges to organisms because seawater: 1. Has high viscosity 2. Variations in salinity 3. High transparency 4. Change of pressure with depth Marine organisms have various adaptations for the conditions of the marine environment 1. Seawater’s viscosity controlled by temperature Condition: – Seawater’s viscosity (resistance to flow) is strongly affected by temperature – Cold water has higher viscosity than warm water, so is more difficult to swim through – Warm water has lower viscosity, so organisms tend to sink within the water column  Density How dose temperature affect density? Decreasing temperature increases density; cold water is denser. Molecules are slower at colder temperature and more concentrated. 1. Seawater’s viscosity controlled by temperature Adaptations: – Many warm- water organisms have ornate appendages to say afloat – Many cold-water organisms are Warm-water Cold-water copepod copepod streamlined to swim more easily  2. Variations in salinity Condition: – Coastal environments experience greater salinity variation than the open ocean or at depth Adaptations: – Many shallow-water coastal organisms can withstand a wide salinity range (are euryhaline) – Most open ocean and deep-water organisms can withstand only a small change in salinity (are stenohaline)  Osmosis Adaptations:  3. Seawater’s high transparency Condition: – Seawater has high Camouflage transparency Adaptations: http://www.youtube.com/watch?v=PmDTtkZlMwM – Transparency – Camouflage Countershading – Countershading – Migration (DSL) 3. The deep scattering layer (DSL) A zone of biological origin within the ocean, at a depth of 270 –360 meters Organisms within the deep scattering layer undertake a daily migration to hide in deep, darker waters during daytime 4. Increase of pressure with depth Condition: – Pressure increases rapidly with depth Adaptations: One adaptation is that lungs and rib cages collapse (flexible) when diving to deep depths. The leatherback sea turtle can dive to over 100 meter. Its collapsible lungs and flexible shell help it stand the high-water pressure.  Leatherbacks can dive to depths of 1371 meters—deeper than any other turtle— and can stay down for up to 85 minutes. High concentrations of hemoglobin and red cells in their blood and myoglobin in their muscles, enhancing oxygen storage during dives. The turtles can also move the oxygen into their bloodstream even when lung oxygen levels are very low. Decrease their heart rate while diving. In a study of diving leatherbacks, heart rates decreased about 30 percent for dives of less than 10 minutes. One turtle’s heart rate declined from 27 beats per minute at the surface to 3.6 beats per minute during a 34-minute dive. Some turtles’ heart rates briefly go as low as 1 beat per minute during dives. https://www.youtube.com/watch?v=xqKQ0NlA4T0 Warm blood flowing out of the core of the seal’s body and towards its flippers dumps heat to cool blood returning from the flippers to the core of the body. This ensures that valuable heat isn’t lost while blood is in the seal’s flippers. This process is called counter-current heat exchange. Ocean Life Zones intertidal nearshore zone open zone ocean sunlit photic region zone 200 meters “twilight” region aphotic zone 1,000 meters darkness  Rocky shores Also called rocky intertidal zone – many places to live in this habitat, means high biodiversity Organisms must be adapted to wave action, changing tide levels  Mostly Spray or Splash Zone shelled orgs High Tide Zone 80-10nurs Middle Tide Zone Many soft Low Tide Zone bodied orgs and algae  Spray zone: dry, desiccation, air exposure, not many species, mostly exposed to physical stresses. High tide zone: only covered at high tide, both biological and physical stresses. Middle tide zone: regularly covered by water, more diverse, more time to submerged and less time exposed to physical stresses. More competition. Low tide zone: usually submerged, only exposed at very low tides. Not many physical stresses, mainly biological stresses.  Upper limits determined by physical stresses (desiccation/temperature fluctuation).  Lower limits determined by biological stresses (predation/competition). To prevent physical stresses own - parking spot  Limpet The limpet is a gastropod, a soft-bodied invertebrate Mollusca They return to the same place on their rock each night. No one knows exactly how they find their way back to the same spot each time. Refer as “home scar”. dislocation warm prevent the rock fit on to  Environmental constraints Submerged by incoming tides Exposed to air, heat, cold and desiccation to low tide Wave shock  Physical adaptations Thick shells are defense against predators and desiccation Produce antifreeze compounds in tissues Flattened body or shell that dissipate the force of waves  Mussels secrete byssal threads to securely attach to underwater surfaces and withstand the high forces exerted by waves. During formation of a byssal thread, glands along the mussel foot secrete a mixture of byssal collagens that self-assemble and solidify into the thread shaft and the adhesive plaque. the rock Attach on to eat them Pack tyt + harder for predator , closely https://www.youtube.com/watch?v=4vWtkzwFnS0 Hydrothermal Vent Communities  Ocean floor – Hydrothermal vent communities have been discovered in 1977 on the ocean floor where tectonic plates are separating (~1500m) These vents, called “black smokers,” emit superheated water rich with sulfur and minerals In this community, sulfur bacteria serve as the primary producers, harvesting energy from hydrogen sulfide released from cracks in the Earth’s surface in a process called chemosynthesis https://www.youtube.com/watch?v=xFAu8CqCtR8 https://education.nationalgeographic.org/resource/oce an-vent/  Ocean floor – Many of the bacteria are free-living and are fed upon by mussels, clams, sea anemones, crabs, and fish – Others live within the bodies of giant tube worms, which lack guts and get all their nourishment from the bacteria – These tube worms may live for 250 years – Organisms in this unique ecosystem—including giant tube worms and snails with iron-laden armor plate—can tolerate temperatures up to 106ºC  Hydrothermal vent snail http://www.wired.com/2015/02/absurd-creature-of-the-week-scaly-foot-snail/#slide-1 No digestive system Freshwater Wetland Habitats  Most of the water on earth is in the oceans ~97% Most freshwater aquatic systems – lakes, rivers and wetlands are dynamic environments Water depth, velocity, turbidity, temperature, oxygen concentration change daily  From Stream to River to Sea bacteria more rain and snow Or high Or level -> consume plankton Or level lower tributary bass source region lement set down transition zone washl i floodplain ocean trout estuary > - great blue heron secement accumulate catfish here Stream and River  Streams and Rivers Streams and rivers collect and transport surface water – Streams often originate in mountains, the source region, where runoff from rain and melting snow cascades over impervious rock Little sediment reaches the streams here, phytoplankton is sparse, and the water is clear and cold Algae adheres to rocks in the streambed, where insect larvae find food and shelter Turbulence oxygenates the water, providing home for trout, which feed on insect larvae  Streams and Rivers – At lower elevations, in the transition region, small side streams merge This forms wider, slower-moving streams and small rivers where the water warms slightly More sediment is carried in, providing nutrients for aquatic plants, algae, and phytoplankton Black bass, bluegill, and channel catfish (which require less oxygen than trout) are found here  Streams and Rivers – As the land becomes lower and flatter, the river warms, widens, and slows, meandering back and forth When precipitation or snow melt is high, the river may flood the surrounding land, called a floodplain, depositing nutrient-rich sediment The water becomes murky with sediment deposits from side streams and dense with phytoplankton Decomposer bacteria deplete oxygen in deeper water, but carp and catfish can still thrive where oxygen is low  Streams and Rivers – Rivers drain into lakes or other rivers that ultimately lead to oceans At sea level, the river moves more slowly, depositing sediment The sediment disrupts water flow, breaking the river into small winding channels Saltwater from the ocean mixes with incoming fresh water, creating estuaries  Oligotrophic lakes Freshwater lakes are classified according to their nutrient content – Oligotrophic lakes are very low in nutrients and support relatively little life Many were formed by glaciers and are fed by mountain streams Because there is little sediment or microscopic life to cloud the water, oligotrophic lakes are clear, and light penetrates deeply Fish, such as trout, which require well-oxygenated water, thrive here  Eutrophic lakes – Eutrophic lakes receive relatively large inputs of sediments, organic material, and inorganic nutrients from their surroundings These lakes can support dense plant communities The water is murky from phytoplankton and suspended sediment, so the limnetic zone is shallower than in oligotrophic lakes Lower oxygen level since the metabolic activities of decomposer organisms use up oxygen A Eutrophic Lake  Estuaries Definition: an area in which fresh water from a river mixes with salt water from the ocean; a transition area from the land to the ocean Other names: bay, sound, lagoon, harbor, Ocean The Ocean Area where fresh and salt & water mix River bringing % freshwater to the sea Mountain  Characteristics of Estuaries Water is brackish: a mixture of freshwater and saltwater There is a gradient (gradual change) in the salinity – near the input from the river: 0-5 ppt – in the middle of the estuary: 5-25ppt – at the ocean: >25 ppt 2 solidity. 5 (ppt = parts per thousand, a unit for salinity)  Mobile Bay – one of the largest estuaries in the U.S. Tensaw River Mobile River Mobile Bay Gulf of Mexico Dauphin Island  Estuary animals oysters lobster  Characteristics of Estuaries Very nutrient rich ecosystems  leads to high productivity and high biodiversity Fast-moving rivers and waves carry nutrient-rich particles Sediment settles out in the estuary when the water slows down It accumulates on the bottom (benthic zone) Great place for plants to grow!  Important functions of estuaries: for living things 1. habitat 2. nursery 3. fisheries 4. recreation  Important functions of estuaries: related to water 5. Water purification 6. Flood control (from upstream) 7. Buffer land from hurricanes, absorb storm surge Loss of coastal wetlands in Louisiana made Hurricane Katrina’s effect worse than it would have been  End Tropical Rainforest  30°N Tropic of Cancer Equator Tropic of Capricorn 30°S Key Tropical forest Chaparral Coniferous forest High mountains Savanna Temperate grassland Arctic tundra (coniferous forest Desert Temperate Polar ice and alpine tundra) broadleaf forest Tropical rainforests are located close to the Equator between the Tropic of Cancer and the Tropic of Capricorn. This means that it is always hot – between 20 and 30°C. Why? The sun is overhead at the equator, it is at a rather slant angle at the poles.  The Amazon Rainforest 40% ↓ 2 - 6 One of the most well known rainforests is the Amazon Earth surface Where is the Amazon? South America The Amazon rainforest is the largest rainforest in the world It covers an area about two thirds the size of the US Two thirds of the Earth’s freshwater can be found there BURNED AREAS OF THE AMAZON COULD TAKE CENTURIES TO FULLY RECOVER The Amazon basin - home to about three million species of plants and animals, and one million indigenous people - is crucial to regulating global warming, with its forests absorbing millions tonnes of carbon every year. But when trees are cut or burned, the carbon they are storing is released into the atmosphere and the rainforest's capacity to absorb carbon is reduced.  ~1.2 tons tree stores 1 ton of carbon which is equal to 3.67 tons of CO2 https://cabiblog.typepad.com/hand_picked/2011/06/ever-wondered-how-much-carbon-is-stored-in-a-tree.html  More Facts about Rainforests… Many of the animals found Nearly half of the world’s in rainforests are found no plants, animals, and where else on Earth. microorganisms will be Indigenous people live in destroyed or threatened in rainforests, today, there are the next 25 years due to ~1 Million people living in deforestation. the rainforests. There are about 3,000 fruits Rainforests cover about 6% found in the rainforests. of the Earth’s surface, but About 2000 trees a minute over 50% the plant and are cut down in a rainforest. animals on Earth live in the rainforest.  Tropical rainforest Rainforests are home to more than half of the world’s plant and animal species. By using a lot of carbon dioxide each day, rainforests keep the temperature, humidity, rainfall and wind levels of the Earth stable. The tropical rainforests are known as the lungs of the world. They provide over 20% of the world’s oxygen. Rainforests are a Rich Source of Medicines 25% of the ingredients in today's cancer-fighting drugs come from organisms found only in the rainforest. Some of the compounds in rainforest plants are also used to treat malaria, heart disease, bronchitis, hypertension, rheumatism, diabetes, muscle tension, arthritis, glaucoma, dysentery and tuberculosis. Commercially available anesthetics, enzymes, hormones, laxatives, cough mixtures, antibiotics and antiseptics are also derived from rainforest plants and herbs. An area of tropical rainforest the size of a football pitch is lost every second. every second  14%  6% Tropical rainforests used to cover 14% of the Earth’s surface. Now they only cover 2-6%.  28 Birds (1) Emergent layer The emergent layer of the rain forest is the highest in elevation marked by the tallest trees randomly protruding upward from 20 to 50 meters from bases of up to 5 meters in diameter. Animals that live in the emergent layer are exposed to more elements than animals protected under the umbrella of leaves and branches. Animals there get around by flying, gliding, or crawling and are generally small, as the tree tops cannot support heavy weight.  Emergent Layer Animals The uppermost layer of the rainforest is the emergent layer, an area characterized by some trees considerably taller than the rest in the rainforest. This area receives the full effects of any weather in the rainforest. Animals capable of flight are the main species found here, with various bats and a multitude of butterflies comprising many of them. The harpy eagle is a major predator of the rainforest; this raptor can weigh as much as 20 lbs. and can kill with its sharp long talons. The pygmy glider is another resident of the emergent layer, being a mammal so tiny that it can glide through the air by extending flaps of skin between its legs.  Emergent-Layer Birds Two major type of bird: macaw and the hummingbird including the bee hummingbird, which is the smallest bird in the world.  Macaw The macaw is the largest of all parrots and there are 16 different varieties. They are considered intelligent, social animals that like to nest in holes in trees in the emergent layer. Size ranges from 1 to 3 feet, with long, colorful tails. Live on nuts, fruits and seeds and have sharp, hooked bills that enable them to crack open nut pods. Strong gripping feet with two toes pointing forward and two toes pointing backward so they can grab their food and bring it to their mouth. to neutralize the toxin clay. Eat  http://www.youtube.com/watch?v=7Ljm1Zm dySo  Why clay? Today, clay is being rediscovered not only for mud baths and facials. To neutralize alkaloids from the seed they feed on. Clay blind the alkaloid and keep them from being poisonous. The Draco Lizard Gliding Frogs  Pygmy Gliders One small animal that makes its home in the emergent layer is the pygmy glider. It protects itself from eagles by feeding at night on insects, buds and tree sap. It can move around easily by using flaps of skin that stretch between its front and back legs to glide from branch to branch. It has tiny treads on its feet for a better grip and sharp claws on fingers and toes for safe landings. During the day, the pygmy glider sleeps in a group in a leaf-lined hole in a tree, invisible to its hungry neighbors.  http://www.youtube.com/watch?v=WOfWejQ fyKk http://www.youtube.com/watch?v=FxSGpCOt kSc (2) Canopy Layer Animals  Sloth There are two species of sloth, the two-toed and the three-toed. They have short, flat heads and are about the size of a small dog, weighing around 20 pounds. Sloths can stay in the same tree for years and can live up to age 30. They are nocturnal and sleep for up to 18 hours at a time usually hanging upside down.  Because they are often covered with algae, their fur blends in with the trees around them. They live high up in trees. the sloth moves so slowly that green algae actually covers its otherwise gray and brown fur. Use their claws to slash at their predators in an effort to scare them away or wound them. Very slow movements help to camouflage them, as faster movement is easier to detect in the dense forest. The sloth's economy of movement and food intake impart a slow metabolism, enabling them to survive with little food.  http://www.youtube.com/watch?v=ndMKTnS RsKM http://www.youtube.com/watch?v=ES32UFlP OUA