Presentation on theme: "VCE Biology Unit 2 Area of Study 01 Adaptations of Organisms"— Presentation transcript:
1VCE Biology Unit 2 Area of Study 01 Adaptations of Organisms Chapter 13.2Environmental factors and adaptations
213.2 Living in water Good place to live. O2 and CO2 and N are dissolved from atmosphere.O2 also released from as by-product of photosynthesis and CO2 released as a by-product of respiration.Mineral nutrients (phosphates, nitrates, chlorides, sulfates and carbonates) dissolved from land.Run off from fertilised lands brings increased amounts of nutrients to the water.
313.2 Living in water Abiotic factor – pH pH – determined by amount of CO2 dissolved in water, which forms carbonic acid (H2CO3).pH of inland waters 6 – 9.Too much CO2 in water (low pH) will kill off fishAcid water (like acid soils) deficient in mineral nutrients
413.2 Living in water Abiotic factor – Temperature Water retains heat very well. Water absorbs and releases heat with little change in temperature.Aquatic habitats usually not affected by drastic temperature fluctuations.Deep water lakes have temperature layering (fig 13.2, page 246). As water warms up it becomes lighter. This creates different temperature environments
613.2 Living in water Abiotic factor – Light Water allows light to reach photosynthetic organisms.The quality of light changes with depth (see figure 13.3 page 247)Turbidity also affects penetration of light: the muddier the water the less light can penetrate. Few plants grow in muddy water
813.2 Living in water Adaptations of billabong animals Pygmy perch (Nannoperca sp.) small native fish that lives in slow moving waterFactor affecting Pygmy perch is competition from introduced species (carp, trout, mosquito fish [Gambusia affinis holbrooki])Waterboatmen also found in slow moving water. They have long paddle like feet to help them move across the surface of the water
1213.2 Living in water Adaptations of plants living in water Hydrophyte (water loving) plants – water low levels of [O2] and light compared to air.Aquatic vascular plants include rooted emergence plants e.g. reeds (Fig 13.6(a) p. 248), and crop plants e.g. rice.
1313.2 Living in water Adaptations of plants living in water continued Water lilies have roots anchored in mud with their leaves (filled with air spaces) floating on the surface (Fig 13.6(b) p. 248).The leaves have stomata only on the upper surface of the leaves.
1413.2 Living in water Adaptations of plants living in water continued Submerged sea grasses have their roots and shoots under water (Fig 13.6(c) p. 248).Leaves are flat with increased surface areaFew stomataVery thin cuticleGases diffuse between water and plant across the entire leaf surfaceSpongy tissue in leaves and stems ‘traps’ O2 from photosynthesis to be used for respiration in the roots.Small amount of transport tissue (xylem)
1513.2 Living in water Xylem and Phloem - Transport systems in plants Phloem transports sugars and other organic compounds through plantXylem transports water and mineralsSee Chapter 9 section 3 pages 161 – 167
2013.2 Living in waterDistribution of marine life on rocky shores ppEnvironmental factors change with position on shoreZonation determined by tideRising tide submerges organisms in sea waterFalling tide exposes organisms to airFrom low to high tide marks – graduation of increasing exposure to drying wind, sunlight, high temperatures during and low temperatures during night.
2113.2 Living in water Zones Supratidal – above high tide Spray – between average high tide and extreme high tideIntertidal – between average low and high tidesSubtidal – below average low tide
2413.2 Living in water Subtidal Zone Least stressful zone e.g. algae – most abundant brown kelp (strongly attached to rocks by holdfasts)Long floating fronds for photosynthesis, some have air-filled bladdersSmall red algae (epiphytes) live on brown kelp.
2513.2 Living in water Intertidal (Littoral) Zone Brown algae (Hormosira banksii) (also known as sea grapes or Neptune’s necklace)Protected from drying winds and high temperatures by a covering of sticky mucilage and water-filled bladders.Green and red algae live amongst brown algae.
2613.2 Living in water Intertidal (Littoral) Zone Herbivorous and carnivorous molluscs live amongst algae.Retreat into hard shells for protection.Barnacles do not move; when exposed to air they close their hard shells, when exposed to sea water they open up and filter water for nutrients.
2713.2 Living in water Intertidal (Littoral) Zone Rock pools provide places of refuge for sea stars, some fish, crabs, etc.Water temperature varies greatly depending on depth, length of time of exposure to air
2813.2 Living in water Spray Zone Receives spray and splashes of water Intense exposure to sunlight, evaporating water and concentrating saltExtreme variations in temperature (day - night)Few organisms live hereTolerant of dry conditions
2913.2 Living in water Spray Zone continued Cynobacteria (blue-green algae)CrustoseOrange or yellow lichensSnailsSupratidal ZoneCompletely out of range of sea water.
3113.2 Living in water Adaptations to mangroves Type of plant that can live in intertidal (littoral) zone on muddy soilFluctuating salinity levels (tides and freshwater from streams/rivers)Lack of O2 at rootsAquatic environment for seed dispersal
3513.2 Living in water Adaptations to mangroves Getting rid of salt Some mangroves actively pump salt out at roots.Some mangroves have salt-excreting glands on leaves
3613.2 Living in water Adaptations to mangroves Specialised roots O2 normally enter roots through lenticelsMangroves have evolved aerial roots, all of which have lenticelsThese include peg roots, pneumatophores and silt rootsPneumatophores increase surface area exposed to air for O2 uptake at low tide
3713.2 Living in water Adaptations to mangroves Specialised roots continuedCable roots spread laterallyCable roots and pneumatophores provide stability for plantCable roots have fine hair-like roots that absorb nutrients and water
3813.2 Living in water Adaptations to mangroves Seed dispersal Seed are buoyant and adapted for dispersal by water.Some mangroves are viviparous (seeds germinate and young plants whilst attached to parental plant).Young plants drop off with developing root system.Can quickly establish in muddy substrate and not get washed away by waves