Sedimentology and Paleontology Lecture 4: Functioning Morphology and the Echinodermata Flashcards
Define Morphology
The study of shapes
Define functional morphology
The relationship between anatomy and functionality.
Functional morphology allows us to reconstruct basic behavioural aspects of organisms.
What is order ranging from reliability and assumption making when deducing functionality of fossils.
Reliable/Reliability —————————> Assumptions
Empirical evidence , Homology, Analogy, Biomechanical studies
When deducing functionality from fossils, what is empirical evidence?
Empirical evidence is direct evidence of something in a fossil. For example direct evidence of functionality in the form of a body part of a fossil.
Direct evidence of functionality, biological processes, or behavior.
When deducing functionality from fossils, what is homology?
Comparing fossils to living versions of the same species, providing they are still alive today.
When deducing functionality from fossils, what is Analogy/Analogous anatomies?
Anatomical traits of distantly related organisms that share functionality. Or similar features that evolved entirely separately, For example wings in bats, birds and pterosaurs.
When deducing functionality from fossils, what is Biomechanical studies/biomechanics?
Using principles and software’s of physical engineering to model anatomies and anatomical forms.
Describe Echinodermata
Echinodermata includes; crinoids (sea lillies), echinoids (sea urchins), asteroids (starfish), Ophiuroids (brittle stars) and sea cucumbers (holothuroids)
- Ranged from Cambrian to recent.
-6000 living species in all manner of marine environments.
Describe the anatomy of the echinodermata
-Skeletons comprised of porous mono crystalline calcitic plates.
-These skeletons are mesodermic meaning they lie underneath a thin dermal layer. These skeletons disintegrate rapidly after death.
-Tube feet and the water vascular system (WVS). The water vascular system is hydrostatic pressure/water pressure used to control movement.
- WVS is unique to echinodermata. Podia at tube feet are used in walking, respiration and feeding.
Echinodermata are primarily benthic, but very diverse.
What does this mean?
Benthic means organisms that live on the seabed.
Many echinoderms live on the seabed but there are various other species which do not.
In Echinoderm classification
Define Pelmatazoans
Define Eleutherozoans
Pelmatazoans - Mainly fixed, stalked forms (Meaning have stalk like stems) lacking a complex respiratory system.
Eleuthrozoans - Mobile, non stalked forms(Meaning have stalk like stems).
Describe Pelmatazoa:Crinoidea
- Cambrian to recent
-Palaeozoic heyday
-Small body (Calyx)
-Brachials lined with food groves.
-Stem comprised of columnals
-Fixed to substrate/seabed via stem and holdfast/ Benthic
Althouth there are also non benthic, free living crinoids which use cirri or brachials to move.
Describe Crinoid anatomy and functionality
Crinoids are filter feeders collecting drifting organic material from the water column. Stem elevates feeding apparatus from seabed.
-Modern stalked crinoids are rheoplilic.
-Angle their brachia towards currents
Many crinoids were pelagic, meaning they were attached to; driftwood, buoyancy aids and free living in water column.
Describe Eleuthrozoans: Echinodea
Ranges from Ordovician to recent
Has Irregular and regular forms
Located in mostly shallow marine environments.
Describe echinoid anatomy
divided into 5 sections of ambulacral and
interambulacral plates
Clear pentameral symmetry (organism can be divided into 5 equal parts)
Podia extend through pore
pairs of ambulacral plates
Muscular tubercles anchor
spines
Feeding apparatus formed
from five calcite ‘teeth’ (which is in the peristome/mouth)
Periproct is anus.
Spines Formed from single calcite
crystals
and are Attached to tubercles
on plates
functions: mobility,
stability, and defence.
Echinoids have spikes for defence Some contain neurotoxins and Others snap off and trigger
potentially-destructive
autoimmune responses
