Lecture 16- Australian invertebrates' diversity Flashcards
What are the 6 terrestrial invertebrate phyla?
- Platyhelminthes: flatworms 2.Nematoda: roundworms 3.Annelida: segmented worms 4.Arthropoda: insects etc 5.Onychophora: velvet worms 6.Mollusca: snails etc -invertebrates are the most species rich part of the animal kingdom, and most abundant -possibly 90% of world species
What do Platyhelminthes look like?
- bilateral symmetry
- eye spots (light sensory)
- dorso ventrally flattened in transverse section
What are the two main types of Platyhelminthes?
- Free living: e.g. brown striped flatworm, some flatworms are brightly coloured, most quite small constrained to small size 2. Parasitic: e.g. tapeworm from vertebrate digestive tract, often quite well develop interaction, some have complex life cycles, even more hosts
What do Nematoda look like and what are their characteristics?
-large groups -(roundworms):
some free-living, mostly parasitic
- e.g. in kangaroo gut, non harmful to the animal
- extremely sophisticated!
What do annelida look like and what are their characteristics?
- segmented worms, like earthworms for example
- metamorphic segmentation, both on the inside and outside
- more complex body structure
- some grow very big:Giant Gippsland Earthworm up to 3m long!!!
- leeches: parasitic -also many in marine environment -e.g. rainforest groups: turquoise earthworm
What are the key unifying characteristics of arthropoda?
-largest invertebrate group in terrestrial systems 1. exoskeleton (external) & 2. jointed legs -
What are the characteristics of subphylum of Arthropoda the Chelicerate?
-(no antennae): spiders, mites, ticks & scorpions -very abundant group, 39000 species of spiders in Australia alone
What are the characteristics of spiders?
-many are active hunters and have venom to subdue or kill their prey, have fangs (inject the venom) -or have webs - some sp. exhibit maternal care: female carrying her young (e.g Wolf spider)
What are the characteristics of scorpions?
-some are active hunters, some wait and then attack -in the arid zone -sting in their tail -also in rainforests
What are the characteristics of subphylum of Arthropoda the Crustacea?
-2 pair antennae branched legs e.g. crabs, slater (pill bug) etc -most are marine
What are the characteristics of subphylum of Arthropoda the Myriapoda?
-1 pair antennae centipedes, millipedes -myriapods= many legs
What are the characteristics of subphylum of Arthropoda the Hexapoda?
-insects: butterflies, moths, ants, beetles etc. amazing diversity in morphology & ecology -good for experiments, as cheap, can manipulate, can have many in an experiment
What is the value of invertebrate models in connection to climate and species distribution?
-Common Brown Butterfly -distribution: correlates with winter rainfalls and milder temperature -
What is the life cycle of Common Brown Butterfly?
-tiny larvae and eggs probably most susceptible to dryness and heat -project to test this -and yes highly susceptible to desiccation and heat, so can’t adapt quickly
How was the experiment with butterflies done?
• Portable weather- station: macroclimate data (air temp, rainfall, wind-speed etc.) Air temp • measured Computer programs: reconstruct microclimate from macroclimate data • Data-loggers: temp & humidity in grass tussocks (sun/shade) -this was to confirm the lab results, and yes!
What are characteristics of the Phylum Onychophora?
-(velvet worms) early lineage links to arthropods -closer related to arthropods than to worms
What are characteristics of the Phylum Mollusca?
-huge group in marine environments -snails etc.
What are the fossils of invertebrates found in SA?
-Invertebrate fossils in SA: 600MY -also Jurassic dragonfly (approx 190MY) -have quite a few fossils in Australia -dragonflies still have the same body plan
What are the origins of Australia invertebrate faun?
- Gondwanan groups e.g. freshwater worms 2. Asian elements e.g. bird eating spiders 3. Archaic element: descendants of widespread Pangean (when world was Pangea) groups, primitive cockroaches, scorpion flies, velvet worms
What are some more characteristics of Onychophora (velvet worms)?
-up until DNA studies not many species 70 worldwide, with DNA testing 40 more genera and only in Australia have 40 species -all of them have similar body plan, similar habitat so *Allozyme (allele codes for particular enzyme or proteins= can inform us about population relations) studies on Euperipatoides leukartii: more species including E. rowelli * Euperipatoides rowelli mtDNA & micro satellite studies: found a # of divergent groups! -habitat: woods
What was the study with velvet worms?
-velvet worms live in wet environment often, rotting log -habitats are small, many geographical barriers on a small scale -have area with one species and another one with another species, the overlapping zone= should have hybrid babies with defects, -the species vary by 20% in their DNA! a lot! -Birth defects in a velvet worm due to “out-breeding depression” (this is due to 2 distinct species interbreeding) low fertility & 5% of young have birth defects, e.g. missing legs -the hybrid zones supported the DNA results
How does reproduction work in velvet worms?
- not romantic
- male comes along, puts sperm on the body of female, there her body will break down and the sperm will get into the reproductive system of the female
- can have up to 25 embryos in her, at different development stages, this is as she can control when the sperm starts developing
- tested for paternity, multiple fathers!
= mate selection! maximum change for offspring success
