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Adaptations of Organisms to Lotic Habitats By: Victoria Lewis Natalie Jackson Nancy Jones Ruth Starr-Keddle.

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Presentation on theme: "Adaptations of Organisms to Lotic Habitats By: Victoria Lewis Natalie Jackson Nancy Jones Ruth Starr-Keddle."— Presentation transcript:

1 Adaptations of Organisms to Lotic Habitats By: Victoria Lewis Natalie Jackson Nancy Jones Ruth Starr-Keddle

2 Introduction H In lotic systems, the velocity of flowing water is a major influence on: Àsubstrate type, with boulders deposited in fast-flow and fine sediments in slow-flow areas, Átransport of particles, either as a food source for filter- feeders or, during peak flows, as scouring agents, Âmaintenance of high levels of dissolved oxygen.

3 H A stream or river contains heterogeneous micro-habitats interspersed with; Àriffles, Ádeeper natural pools, Âerosion of banks, Ãsediments deposited, Äareas of unstable, shifting sandy substrates.

4 Adaptations Of Aquatic Plants To Lotic Habitats H Leaves & stems within, or floating on Water. H Upper leaves or shoots able to grow above the water, lower ones able to grow submerged. ÀTall monocotyledons- Grasses, sedges & rushes ÁShort dicotyledons-the fringing herbs-typically found fringing the sides of small brooks ÂShort monocotyledons, mainly grasses, again frequently at the sides of brooks ÃA very few tall dicotyledons H Bank plants growing above normal water level, flooded after heavy rain.

5 Adaptations of Insects to Lotic Habitats H Morphological Adaptations ÀDorsoventral Flattening ÁCase Construction ÂSuckers ÃSilk Nets ÄSize H Behavioural Adaptations ÀUse of Drift ÁBurrowing

6 Morphological Adaptations H Dorsoventral Flattening ÀAllows the organism to stay close to the substrate where there is a layer of still water. An example of this is the Water Penny. H Case Construction ÀA variety of case shapes made by caddis fly larvae assist in streamlining and act as a ballast.

7 Morphological Adaptations H Suckers ÀAllows the insect to stick to quite smooth exposed surfaces such as rock faces or in waterfalls, some Diptera larvae use this. H Silk Nets ÀUsed to maintain position in flow. Blackfly larvae attach their claws to a silk pad attached to a rock.

8 Morphological Adaptations H Size ÀBeneficial to be smaller and have flexible bodies, allowing them to live in the bed (benthos) of the stream between the boulders, stones and pebbles.

9 Behavioural Adaptations H Drift ÀA drifting stategy can be used to move from an unsuitable location. Some insects such as Baetis follow a diurnal periodic pattern of drift. Catastrophic Drift is used by some as a response to physical disturbance.

10 Behavioural Adaptations H Burrowing ÀInsects will burrow deep into the substrate (the hyporheic zone) where they can avoid fluctuations in the environment.

11 Adaptations of Vertebrates to Lotic Habitats H All 5 phyla possess species adapted to life in lotic habitats;fish, amphibians, reptiles, birds, and mammals. H Streamlined body shapes to reduce friction in water. H Some more specialised adaptations in life history, physiology and morphology.

12 Adaptations of Fish H 8,500 freshwater species. H Salmonoids & Lampreys; DIAROMOUS ÀLampreys larval stage; AMOCOETE ÁSalmonoids can vary their growth rates H CATADROMOUS, e.g. eels H DIADROMOUS GLOBOID; larval stage at sea.

13 Adaptations of Amphibians H 2 common families; URODELA (salamanders & newts), ANURA (frogs & toads). H Eggs laid in freshwater. H Larval stage possess gills, but also use skin for gaseous exchange. H Adults possess lungs but still use their skin as well for gaseous exchange.

14 Adaptations of Reptiles H Some species of snake and turtle are found in lotic habitats. H Crocodiles; ÀEyes, nostrils & ears on top of head. ÁNICTITATING membrane to cover eyes. ÂValves to close ears & nostrils. ÃLong thin body with short legs good for sinuous swimming movements.

15 Adaptations of Birds H Dippers; ÀDense, waterproof feathers. ÁNasal flaps. ÂWings used like flippers when in water. ÃNICTITATING membrane. H Ducks; ÀFew species are confined to a lotic habitat. ÁHarlequin duck, truly lotic.

16 Adaptations of Mammals H Few aquatic species exclusively reside in lotic habitats. H Otters; lutra (genus) ÀStreamlined body shape. ÁBroad flat tail involved in sinuous swimming movements. ÂShort dense fur impermeable to water. ÃLarge lung capacity allowing long dives. ÄPartially webbed feet for swimming.

17 H Platypus; ÀWebbed feet, short fur, Lacks external ears. ÀFeeds on bethic invertebrates. ÀBill covered with soft skin possessing many electrosensors. ÀBroad flat tail used as rudder when diving & surfacing H River Dolphin; Àonly mammal confined to lotic habitats. ÁPoor vision. ÂNarrow, very sensitive sonic beam for location of food & obstacles. ÃSmaller body size than marine dolphin.

18 Conclusion H Some plants and invertebrates have specific adaptations to the lotic environment, and vertebrates tend to be suited to an aquatic environment. H All are linked together in the lotic environment, ie. Submerged plants provide egg-laying sites for invertebrates and fish, and lurking sites for predators.

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