Directed reading Flashcards
Shark embryos
Bamboo shark
•late stage embryo when exposed to predator-simulating sinusoidal electrical field stop respiratory gill movement - minimises electro & mechano outputs
•stage 32 when electrosensory system becomes functional
•older stages like 34 respond to lower Hz than 32 or 33
•repeated exposure = desensitisation
•greatest response to potential predators like teleosts and sharks
Barnacle penises
Diverse penis form that varies according to tidal patterns of environment
Display phenotypic plasticity and vary widely from group-to-group
Those in more wave exposed coasts will have shorter, thicker penises - enabling them to control in harsh water flow
Variability down to constraints in needing to control it but needing to reach enough mates
-risk of it just varying due to leg length though
Sea anemone personality traits
• Winners found to be bolder than losers - have shorter-startle response periods, quicker to recover from perturbation
-negative response between startle repsonse duration and peels inflicted
• Their fighting ability changes as a result of fighting - if they lose, they are more likely to gave a longer period and lose again
-increased caution being beneficial to avoid further injury?
Clearly demonstrates behavioural plasticity
Cichlid diversity
•F show strong preference for conspecific male when olfactory cues present
-chemical communication
•links with olfactory-related mate preference and the major histocompatibility complex and F preference for genetically dissimilar Ms
•M colour divergence driven by male competition ?
-as it has evolved without F preference
-may reduce territorial aggression so can establish territory quicker
Coral larvae move towards reef sounds
•free swimming larvae moved towards reef sounds (like crustaceans and fish calls/grunts)
•showed by horizontal and vertical directional movement to reef noises
•likely the coral respond to particle motion - detection distance limits from 10s-100s meters
•also been demonstrated they have photo, mechano and chemo receptors
-implications for noise pollution
Shark skin
Lesser spotted dogfish
•dermal denticles - a new function
•external manipulation of food - juveniles don’t have as much biting power
•attach food where denticles are larger - lateral-caudal body region
•head moves rapidly away from the region creating an opposing force necessary for small pieces of food to be grasped and removed from main part
•adults denticles are an order of magnitude smaller - food anchoring less successful, explaining low frequency of occurrence
Dolphin electroreception
- vibrissal crypts have been transformed into an electroreceptive system - previously seen to be vestigial in other marine mammal species, like other toothed whales
- contain sense innervation and a blood supply - supporting that they’re functional
- ampullary shape similar to the Ampullae of Lorenzini found in sharks
Eel raptorial jaws
•drag large prey items into gullet with second pair of grasping jaws - thrust forward from deep in throat
•different to other pharyngeal jaws - has ability to reach far forward from resting position in pharynx
-ells don’t use suction feeding so possibly an adaptation in response to pressures from this
Fatal attraction in rats
Toxoplasma gondii
•alters its intermediate host’s behaviour
•subtly altering brain chemistry to reverse the anti predator reaction it would normally have to a cat (the definitive host)
•rats now attracted to cats odour, increasing likelihood of predation by the cat and transmitting the parasite
Malaria infected mosquito behaviour
Plasmodium
•alter vector - a mosquito, behaviour to enhance transmission
•alters the vectors attraction to the smell of the host (human)
•suggested to cause changed in olfactory region - alteration of odourant-binding proteins (OBPs) or olfaction receptors, as malaria infected mosquitos will land and probe more at a surface with human odour than mosquitos that were not infected
Whale bone-eating tube worms
Male dwarfism
•natural selection driving force - where females are sedentary and hard to find
•Ms live in Fs tube
•worms are gutless and mouthless, relying on endosymbiotic bacteria living in bacteriocytes to provide the host with energy
•F has short time to reproduce (bones only last a few years)
•environmental sex determination - when larva settles on whale bone becomes F, when on F tube worm becomes M
•no direct evidence tho
Mimic octopus
•most obvious impersonations are on animals that produce strong toxins
•likely to be batesian mimicry as the fact is employs camouflage and predator avoidance suggests its not toxic
-and batesian mimicry favours a range of models as means there are more novel encounters to the mimic - less likely to recognise it isn’t the real animal
•dynamic mimicry enabled by lacking a rigid skeleton so can adopt different shapes, and can change colour via chromatophores
Snails love darts
- the love dart injects mucous - as well as stimulating the target mechanically
- it is the mucous that is the important part (mechanical simulation alone is not enough)
- mucous causes contractions in snails spermatophore receiving organ - allowing allosperm to avoid enzymatic digestion and to head for the spermathecal storage sacs
Spider that eats mosquito
•indirectly feeding on vertebrate blood
•consistently chose females carrying blood than those not
-innate preference for blood-fed females, as the individuals used had never been exposed to or had experience with blood meals previously
•these spiders don’t have the specialised mouth parts of mosquitoes for piercing into vertebrate skin and ingesting blood
-selection acting on individuals that can pick these individuals
