Transcript Chapter 13
INTERTIDAL COMMUNITIES Part of Chapters: 2, 4, 5, 11, 13, 20 Study of Ecology Environment: All of the living and non-living factors of an area. biotic factors: living factors (animals, plants, fungi, ect) abiotic factors: non-living factors (wind, temp, currents, salinity, ect) Habitat: a place where an organism lives Niche: the role an organism plays in their environment. No two species can have the exact same niche. Populations and Communities Population : A group of the same species in a specified area. Community : Many different populations in a specified area. Populations and Communities Population growth there are many ways in which a population can increase in size Birth and immigration exponential growth: drastic growth in a short period of time. carrying capacity: the amount of organisms a specific area can support without running out or degrading resources. Populations and Communities Distribution of marine communities pelagic division: all the water in the oceans neritic zone: water above the continental shelf. pelagic zone (oceanic zone): all the water pass the neritic zone (covers the deep areas) photic zone: where sunlight can penetrate and support photosynthesis disphotic zone: minimal sunlight can reach. Not enough for photosynthesis aphotic zone: no sunlight Plankton: organisms that drift with currents Nekton: organisms that can swim against currents Populations and Communities Benthic division: The ground below the water in the oceans Shelf zone: area that extends from high tide line to the continental slope Bathyal zone: Below the shelf zone Abyssal zone: Below the Bathyal zone (the deep) Hadal zone: Below the Abyssal zone. Deepest areas in the oceans. Usually found in trenches. Epifauna: Organisms that live on the sea bottom Infauna: Organism that live in the sediment of the sea bottom Characteristics of the Intertidal Zone Daily fluctuations of the environment organisms must tolerate radical changes in temperature, salinity and moisture, and endure the crushing force of waves Inhabitants are most active during high tide, when area is submerged water provides food for filter feeders As the tide retreats, organisms adjust to exposure to air and sunlight Environmental Factors Affect Organism Distribution Maintaining homeostasis (internal balance) Affected by changes in external environment internal adjustments made to maintain a stable internal environment homeostasis and the distribution of marine organisms Optimal Zone range: of stress: Zones of intolerance: Environmental Factors Affect Organism Distribution Physical environment sunlight Photosynthesis Vision Desiccation temperature Ectotherms: Endotherms: Environmental Factors Affect Organism Distribution Salinity: Solutes: Osmosis: Isotonic: Hypertonic: Hypotonic: Environmental Factors Affect Organism Distribution metabolic requirements nutrients and limiting nutrients oxygen as a requirement for metabolism anaerobic and aerobic organisms Eutrophication: metabolic carbon wastes dioxide is a common byproduct of metabolism Environmental Factors Affect Organism Distribution Biological environment Competition interspecific: intraspecific: competitive exclusion: resource partitioning: predator-prey balance relationships of abundance of prey vs. predators keystone predators: Tides Why tides occur tides result from the gravitational pull of the moon and the sun though smaller, the moon is closer to earth, so its gravitational pull is greater water moves toward the moon, forming a bulge at the point directly under it the centrifugal force opposite the moon forms another bulge areas of low water form between bulges Tides Spring and neap tides during spring tides, the times of highest and lowest tides, the earth, moon and sun are in a line, combining the pull of the sun and moon when the sun and moon are at right angles, the sun’s pull offsets the moon’s, resulting in neap tides, which have the smallest change between high and low tide Tides Types of Tides: Diurnal: Semidiurnal: mixed Tidal semidiurnal: range: Waves Wave formation Wave: Generating force: most common = wind also geological events, falling objects, ships Restoring force: Waves deepwater and shallow-water waves deepwater waves: breakers deepwater waves become shallow-water waves when they move into shallow water surf zone: breakers form when the wave’s bottom slows but its crest continues at a faster speed plungers form when the beach slope is steep spillers are found on flatter beaches Waves tsunamis seismic sea waves are formed by earthquakes tsunamis have long wavelengths, long periods and low height compression of the wave’s energy into a smaller volume upon approaching a coast or island causes a dramatic increase in height Intertidal Zonation Zonation—separation of organisms into prominent horizontal bands defined by color or distribution of organisms As tide retreats... upper regions exposed to air, changing temperatures, solar radiation, dissication lower regions exposed only a short time before tide returns to cover them Intertidal Zonation Supralittoral (maritime) zone: Supralittoral fringe (splash zone): Intetidal Zonation Zone system (continued) Midlittoral zone: Infralittoral Subtidal fringe: (infralittoral) zone: Intertidal Fishes Resident species typically have special adaptations for surviving harsh intertidal conditions small size; absent, reduced or firmly attached scales; compressed/elongate or depressed body shape; absent or reduced swim bladder; greater body density tolerant of temperature and salinity changes some intertidal fish can leave the water to feed Temporary inhabitants tidal, seasonal and accidental visitors Rocky Shores and Sandy Shores Rocky shores are found on the west coast from Alaska south and on the east coast cape cod north. Have all 5 intertidal zones. Organisms attach to rocky surfaces and create a visiable zoning. Sandy Shores are found mainly on the east coast, cape cod south and along gulf coast. Only have 3 zones (Supralittoral zone, Midlittoral, Infralittoral zone). Does not show zonation because most organisms are found in the sand. Role of Waves and Sediments Sediment particle size influences the beach’s nature, porosity of sediments, ability of animals to burrow Wave action influences sediment type: heavy wave action = coarse sediments little wave action = fine sediments Beach slope results from interaction of waves, sediment particle size, and relationship of swash and backwash Role of Waves and Sediments Swash: Backwash: Types of beaches: dissipative usually flat with fine sediment reflective usually beach: beach: steep with course sediment Role of Waves and Sediments On all sandy beaches, a cushion of water separates the grains of sand below a certain depth especially true on beaches with fine sand where capillary action is greatest Fine sand beaches have a greater abundance of organisms greater water retention sediment is more suitable for burrowing Meiofauna Meiofauna: Characteristics of the meiofauna invertebrates from many phyla generally elongated with few lateral projections many are armored to protect them from being crushed by moving sand grains include predators, herbivores, suspension feeders and detrivores Linnaeus and Biological Classification Binomial system of naming binomial nomenclature: introduced by Swedish botanist Karl von Linné (Carolus Linnaeus) in 1750 e.g. Chaetodon longirostris (long-nose butterflyfish) and Chaetodon ocellata (spotfin butterflyfish) are both in the same genus Linnaeus and Biological Classification Taxonomic categories Early schemes of classification all living things were classified into 1 of 2 kingdoms, Animalia and Plantae, until 1960s Modern classification major categories: domain, kingdom, phylum, class, order, family, genus, and species Domains: Archaea, Eubacteria, Eukarya Kingdoms: Eukarya contains 4 kingdoms, Fungi, Plantae and Animalia, Protista protists—eukaryotic organisms that do not fit the definition of animal, plant or fungus Marine Reptiles Reptiles adapted for success on land, then used the same characteristics to return to the sea and gain success there as well Modern-day reptiles include: crocodilians turtles lizards snakes Amniotic Egg An amniotic egg is covered by a protective shell and contains: Amnion: yolk sac: Allantois: Chorion: Copulatory organs allow efficient internal fertilization Physiological Adaptations Advanced circulatory system in which circulation through the lungs is nearly completely separate from circulation through the rest of the body more efficient method of supplying oxygen Kidneys are efficient in eliminating wastes while conserving water Skin covered with scales and lacking glands decreases water loss Marine Crocodiles Best adapted to the marine environment is the Asian saltwater crocodile (Crocodylus porosus) Large animals (up to 6 m long) Feed mainly on fishes Drink salt water and eliminate excess salt through salt glands on their tongues Lives along the shore, where it nests Sea Turtles Adaptations to life at sea protective shells that are fused to the skeleton and fill in the spaces between the vertebrae and ribs protect their bodies outer layer of shell composed of keratin inner layer composed of bone Carapace: Plastron: leatherback turtle lacks shell and has a thick hide containing small bony plates Sea Turtles Adaptations to life at sea (continued) shell is flattened, streamlined,d reduced in size and weight, for buoyancy/swimming large fatty deposits beneath the skin and light, spongy bones add buoyancy front limbs are modified into large flippers back limbs are paddle shaped and used for steering and digging nests Sea Turtles Behavior generally solitary, don’t interact remain submerged while at sea; breathe air but can stay under water for as long as 3 hours alternate between feeding and resting during the day sleep on the bottom under rocks or coral Sea Turtles Feeding and nutrition have a beak-like structure instead of teeth green sea turtle is the only herbivore leatherback sea turtles eat jellyfish pharynx is lined with sharp spines to hold slippery prey digestive system adapted to withstand stings large amounts of salt consumed with food and water are eliminated as concentrated tears through salt glands above the eyes Sea Turtles Reproduction courtship – males court females before mating; males may compete for a female, or 1 female may mate with several males nesting – females dig shallow pits on the beach, usually at night, and bury eggs development and hatching temperature determines development time and sex ratio hatchlings rush for the safety of the sea after hatching Sea Turtles Turtle migrations females migrate from feeding grounds to the beaches where they were born to nest green sea turtles feed on grasses in warm, shallow continental waters, but breed on remote islands some breed on a 2- or 3-year cycle method for navigation over long distances is unknown Sea Turtles Sea turtles in danger beach erosion artificial lighting near nesting beaches sea turtles are killed when trapped in fishing nests, especially those used for shrimpers turtle exclusion devices can reduce turtle mortality by as much as 95% when used for shrimp nets turtles are hunted by humans for meat, eggs, leather and shells Marine Iguana The marine iguana of the Galápagos Islands off Ecuador is the only marine lizard Most are black, but some are mottled red and black dark coloration is thought to allow more absorption of heat energy raising body temperature allows them to swim and feed in cold Pacific waters Marine Iguana Feeding and nutrition herbivores with a short, heavy snout for grazing on dense mats of seaweed swallow small stones to reduce buoyancy for feeding under water excess salt from consumed seawater is extracted and excreted by specialized tear and nasal glands Marine Iguana Behaviors good swimmers, using lateral undulations of the body and tail each male occupies a small territory on the rocks, usually with 1 or 2 females intruders or challengers are attacked when they enter the male’s territory fights between male iguanas rarely result in serious injury Sea Snakes Adaptations to life in the sea scales are absent or greatly reduced for streamlining tail is laterally compressed into a paddle nostrils are higher on the head valves in the nostrils prevent water from entering when the snake is submerged single lung reaches to the tail, and trachea is modified to act as an accessory lung by absorbing oxygen Sea Snakes Adaptations to life in the sea (cont.) can exchange gases through the skin while under water can lower metabolic rate to use less O2 Feeding and nutrition eat mainly fish and eels, sometimes eggs most ambush prey and strike with venomous fangs can swallow prey more than twice their diameter Sea Snakes Sea snakes and humans sea snake venom is toxic to humans being timid, sea snakes rarely bite humans; people eat them in Japan Seabirds 250 of 8,500 bird species are adapted to live near or in the sea Seabirds feed in the sea Some spend months away from land, but all must return to land to breed Types of seabirds: shorebirds gulls and their relatives pelicans and their relatives tubenoses penguins Adaptations for Flight Homeothermic: Feathers aid in flight and insulate High rate of metabolism to supply energy for active flight/nervous system Strong muscles, quick responses, great deal of coordination Advanced respiratory system with 4-chambered heart Keen senses Adapting to Life in the Sea Large amounts of salt are consumed with food and salt water salt glands above the eyes produce tears to remove excess salt these tears have twice the salt concentration of seawater Shorebirds Waders with long legs and thin, sharp bills used to feed on intertidal organisms Oystercatchers, curlews & turnstones oystercatchers use long, blunt, vertically-flattened orange bills to slice through adductor muscles of bivalve molluscs long-billed curlew uses its bill like a forceps to extract shellfish from burrows Shorebirds heavyset turnstones use slightly upturned bills as crowbars to turn over stones, sticks and beach debris in search of food Shorebirds Avocets, stilts, and sandpipers avocets and stilts have very long legs, elongated necks, and slender bodies avocets wade through shallow water, moving a partially opened beak from side to side through the water, to feed stilts probe the mud for small animals (e.g. insects, crustaceans) with their bills sociable sandpipers feed on small crustaceans and molluscs as the surf retreats Shorebirds Herons (e.g. egrets and bitterns) most stand still and wait for prey to come in range to feed some stalk prey or stir up the bottom to frighten prey into motion so it can be caught Gulls and their Relatives Gulls have webbed feet and oil glands to waterproof their feathers They are not true ocean-going birds, and do not stray far from land Have enormous appetites Are not very selective feeders Relatives of gulls include terns, skuas, jaeger birds, skimmers and alcids Gulls and their Relatives Gulls herring gulls are the most widespread, and are vocal, gray and white, and travel in large groups feeding noisy, aggressive, efficient predators and scavengers may drop prey with hard shells on rocks or parking lots to break the shell open highly successful at finding food and surviving Gulls and their Relatives Gulls (continued) nesting highly gregarious; gather in large colonies not picky about nesting sites or materials both sexes assist in incubating 2-3 eggs chicks hatch in 3-4 weeks, and remain in the nest until almost fully grown, camouflaged by speckled down chicks are vulnerable to predation by other animals and by other gulls Gulls and their Relatives Terns small, graceful birds with brightly-colored and delicatelysculpted bills, forked tails hunt by plunging into the water for fish and invertebrates; will steal food usually gregarious nesters Skuas and jaegers very aggressive omnivores and predators “hawks” or “vultures” of the sea jaegers will pursue other birds to steal their prey Gulls and their Relatives Skimmers (scissorbills) small birds with pupils that are vertical slits and a flexible lower jaw protruding much farther than the upper bill fly over water and use the lower bill to create ripples at the water’s surface that attract fish fish are then collected by flying along the same path over the water a second time Gulls and their Relatives Alcids (e.g. auks, puffins, murres) look like penguins but are related to gulls convergent ecological major evolution: equivalents: difference is that alcids can fly Pelicans and their Relatives E.g., gannets, boobies, cormorants, darters, frigatebirds, tropicbirds Have webs between all 4 toes Upper mandible is hooked in pelicans, cormorants and frigatebirds Many are brightly colored, or have head adornments Pelicans and their Relatives Pelicans large birds preferring warm latitudes and estuary, coastal and inland waters require a large fish population to support colonies of large birds feed just under the water’s surface using gular pouches as nets gular pouch—a sac of skin that hangs between the flexible bones of the bird’s lower mandible Pelicans and their Relatives Boobies dive into the sea from 18-30 m up to fish species lay differing numbers of eggs; this is thought to reflect the reliability of the food supply around where they nest Cormorants swim along the surface scanning for fish, then plunge deep to pursue them lacking oil glands, they must periodically dry their wings in order to fly Pelicans and their Relatives Cormorants (continued) most are strong fliers, but the Galápagos Island species is flightless guano cormorant of the coast of Peru valued for its guano (bird manure) Frigatebirds lightweight body and near 2 m wingspan lacking oil glands, they feed by skimming with their bills pursue/attack other birds to steal prey Tubenoses E.g. petrels, albatrosses, shearwaters Have obvious tubular nostrils on their beaks which join with large nasal cavities within the head Nasal glands secrete concentrated salt solution Stomachs contain a large gland that produces a yellow oil composed of liquefied fat and vitamin A, used for feeding hatchlings and defense Tubenoses Albatrosses gliders with wings nearly 3.5 m long most live in the Southern Hemisphere where winds circle the earth without encountering land usually come to land only to breed courtship displays precede mating 1 egg is incubated by both parents on a volcanoshaped nest, and the young are fed on stomach oil, then regurgitated fish Penguins Bird most adapted to marine lifestyle Awkward on land, but swift swimmers flap their wings to swim torpedo-shaped bodies are streamlined flat, webbed feet are used for steering leap from the water to breathe Eat fishes, squid and krill Eaten by leopard seals and killer whales Penguins Reproduction in Antarctic species adelie penguins lay eggs in summer; emperor penguins in mid-winter female emperor penguin lays 1 egg, which the male incubates for 2 months while she visits her feeding grounds egg sits on his feet, covered by a fold of skin male can feed the chick a secretion from his crop if it hatches before female’s return crop—a digestive organ that stores food before it is processed Penguins female returns with food in her crop for the chick, and male can feed both parents help to feed the chick once it reaches 6 weeks by summer, the chick can feed itself, and is ready to enter the sea