WR locomotion and temperature (5,6) Flashcards
adaptation of gastropods on a rocky shore
Garrity 1984- adaptation of gastropods on a rocky shore
- Pacific coast of Panama
- When experimentally removed from refuge (crevices) to open spaces- microhabitat deemed vital in species such as the limpet Siphonaria mora. Determined via mass lost and relative survival.
- Siphonaria gigas reduced temperature through 1) evaporative cooling, facilitated by curling edges of the foot from home scar and creating mucus layer between foot and substrate to reduce contact- when manipulated they clamped down- predation pressure therefore can reduce the evaporative cooling as foot contact is maximised
- On sunny days Littorinids such as Littorina modesto withdrew into shell and sealed operculum. Orientated shell spire upwards around midday to reduce angle of projection on shell.
- Nerita Scabricosta demonstrates clumping and releases water from shell, animals in the middle of the multilayer clump remain damp.
Mcmahon 1990- Thermal tolerance, evaporative water loss, air-water oxygen consumption and zonation of intertidal prosobranchs: a new synthesis
Physiological
Physiological
• Aestivation- reduction of metabolic processes in periods of prolonged heat by withdrawing into shell, sealing aperture,
Mcmahon 1990- Thermal tolerance, evaporative water loss, air-water oxygen consumption and zonation of intertidal prosobranchs: a new synthesis
Morphological
- Shell morphology of species higher up are more lightly pigmented- allow them to reflect radiant solar heat. Small size aids dissipation of heat- both adaptations serve to reduce tissue temperature.
- Eulittoral species such as Austrochlea constrica are lower shore species are larger and have darker pigmented shells to help with heat absorption and retention.
- Gradient in behavioural adaptation of foot lifting to facilitate evaporative cooling as you go down the shore.
Example of excretory systems and physiological adaptations
Example of excretory systems and physiological adaptations
Emson et al 2002- excretory podocytes in littorinid gastropod Cenchritis muricatus.
- Long term study on water loss and haemolymph concentration of C.muritacus
- Concentration after 20 weeks is 250%
- Initial rapid increase in concentration is followed by slower reduction due to replacement of podocyte-containing filtration chambers in the heart by extracellular tubules permeating the walls of both auricle and ventricle. This reduces urine formation and therefore reduces water loss. Termed ‘uricotelic excretion’. - ABLE TO TOLERATE DESICCATION WELL
- Reduced surface area of the nephridal gland (excretory organ)= smaller production of urine. (reabsorbs solutes from urine)
Invertebrate locomotion
squids throughout ontogeny.
The study
Bartol et al., 2008
Swimming dynamics and propulsive efficiency of squids throughout ontogeny.
Study:
· Digital particle image velocimetry (DPIV) and kinematic data were collected from an ontogenetic range of long-finned squid Doryteuthis pealeii and brief squid Lolliguncula brevis swimming in a holding chamber or water tunnel to determine how swimming dynamics and propulsive efficiency change throughout ontogeny
· A total of 20 paralarval swimming sequences were studied.
Bartol et al., 2008
Swimming dynamics and propulsive efficiency of squids throughout ontogeny.
Results
Results:
- Doryteuthis pealeii paralarvae spent the majority of their time holding station in the water column; they ascended during mantle contraction and descended during mantle refilling.
- The duration of the refill period largely determined net vertical displacement in the water column.
- Study demonstrates that paralarvae have different jet dynamics and propulsive efficiencies than do juveniles and adults; due to the morphological, fluid mechanical, and ecological shifts these life-history stages experience
- Observations supported the idea that a paralarva’s rudimentary fins are thought to contribute little to production of thrust relative to juvenile/adult
- The S. lessoniana paralarvae exhibit higher contraction frequencies than adults during escape jetting
- Paralarval D. pealeii had shorter contraction periods during routine swimming than did adult L. brevis
- Mass-specific metabolic rates are generally higher in hatchlings than in adults- largely attributable to the costs of overcoming relatively high viscous drag forces at low Re
- loliginid squid exhibit greater locomotive flexibility, both in terms of jet and fin dynamics, at sizes42.0 cm DML
Bartol et al., 2008
Swimming dynamics and propulsive efficiency of squids throughout ontogeny
Critical analysis
Critical analysis:
- Findings are consistent with Thompson and Kier (2001) who predicted that velocity of expelled water should be lower in paralarvae relative to adults
- A multitude of fin wake patterns were observed- potentially due to Juvenile and adult L. brevis exhibiting a wide diversity of fin motions, from more wave-like (undulatory) motions to more flap-like motions
Burrowing of sandy-beach molluscs
The study
Brown and Trueman, 1991
Burrowing of sandy-beach molluscs in relation to penetrability of the substratum
Study:
- The Bivalve Donax serra and Gastropod Bullia digitalis mechanisms and energy costs of burrowing-
- § Donax burrowing vertically downwards, Bullia obliquely at an angle of 10 to 15 degrees
- Investigated the penetrability of an area of saturated sand into which the animals were able to burrow
- Penetrability was measured by means of a Model CL700 Penetrometer, pressure being exerted on a spring-loaded piston until it penetrates to a depth of 0.5 cm
- Pedal haemocoelic pressures during extension into the substratum exhibited in both
Burrowing of sandy-beach molluscs
The Results
Results:
- Both can only burrow into fully saturated sand and both produce water jets which liquefy the sand during each digging cycle.
- Donax probes the sand with its foot as a first phase of burrowing, Bullia does not
- Donax, must probe the sand to liquefy it sufficiently to allow pedal penetration, whereas Bullia can afford to burrow by a simple extension of surface crawling
- The mechanical energy cost of burrowing must be very much greater in Donax than in Bullia
Burrowing of sandy-beach molluscs
Critical anaysis
Critical analysis:
· Penetration of the sand using a metal piston in no way simulates penetration by the foot of a living animal, which presumably is adapted to using the least force to achieve the desired effect.
A comparative analysis of the locomotory systems of medusoid Cnidaria
The study
Gladfelter, 1973
A comparative analysis of the locomotory systems of medusoid Cnidaria
- · Surveyed a broad taxonomic spectrum of hydro- and scyphomedusae examining the pattern of locomotory structures and function where possible, in order to draw generalizations about fundamental characteristics of medusa swimming mechanisms.
- · The locomotory systems of forty-two genera of hydro- and scyphomedusae, representing nine orders, were surveyed, to serve as a basis for generalizations about medusan locomotion
- · Many forms are slightly negatively buoyant, and some locomotory ability is necessary to maintain the animals in the water column.
- · It is important for animals to be able to change their position with respect to possible food sources in the surrounding water; the most dramatic example of this is the diurnal vertical migrations undergone by some medusae, correlated with optimizing feeding stations.
Lecture 8: Polar Seas – Adaptation to the Cold
(Sommer & Pörtner, 2002)
Metabolic adaptation to the cold of Arenicola marina (Lug worm) - Study
- Mitochondrial mechanisms – may define an organism’s thermal tolerance window
- Two intertidal populations of A.marina from two locations tested: North sea (boreal) and White sea (subpolar)
- North Sea (higher mean annual temperature, ~10°C) and White sea (lower mean annual temperature, ~4°C)
Metabolic adaptation to the cold of Arenicola marina (Lug worm)
(Sommer & Pörtner, 2002)
Results
- Results:
o 2.4X higher mitochondrial density in muscle tissue in White sea population
o Overall rise in capacity of aerobic energy production with cold adaptation
o At extreme temperatures (25°C) lugworms from the White sea showed a drastic increase of oxygen consumption – this indicates that ‘energy-consuming’ processes may be involved In the mechanisms for improved thermal tolerance.
Study on the blood of a high-Antarctic fish
(Kunzmann et al., 1991)
Study
- Focussed on 1 Notothenioid species: Bathydraco marri
- General trend of reduced number of erythrocytes and haemoglobin has been reported in all Notothenioid families
- “Lack of haemoglobin and reduced erythrocytes is regarded as a mechanism of evolutionary adaptation. Therefore the Channichthyidae (ice fish) are the most advanced group of fishes in the Antarctic as they have a total lack of haemoglobin and only a few erythrocyte-like cells.”
- In large tanks B.marri showed a low level of routine activity, resting on the bottom for most of the time
- However, when disturbed, demonstrated prolonged and high level of activity – swims with fast bursts of the tail in zig-zag patter for up to 3-4 minutes – this behaviour is still observable in individuals which have been in captivity for >2 years – innate behaviour
- Reduced haematocrit and low haemoglobin means oxygen bust be transported in plasma
- O2 solubility in plasma (0.8 vol %)
- Total O2-carrying capacity was calculated to be 4.76 vol % in blood and 27.9 vol % in erythrocytes.
- Contribution of plasma to the total O2-carrying capacity in stressed individuals is at least 16.7%: 1/6 of the total O2 transported in blood is therefore carried by physical solution in plasma
- Not negligible.
Lecture 9: Polar Seas – Adaptation to Warming
(Place & Hofmann, 2004)
Stress inducible HSP (heat shock protein gene, hsp70, expressed in phylogenetically distant Antarctic fish
study
(Place & Hofmann, 2004)
Stress inducible HSP (heat shock protein gene, hsp70, expressed in phylogenetically distant Antarctic fish
- HSPs can be either constitutive (transcribed continuously) or inducible (only transcribed when needed)
- hsp70 – inducible
- hsc71 – constitutive
- study examined the expression of these two genes in three fish species:
- Trematomus bernacchii and Pagothenia borchgrevinki – two closely related notothenioid species
- Lycodichthys dearborni - phylogenetically distant Antarctic species
