1. Holoplankton:
Planktonic throughout life
I.e. Rotifers, Claudocerans, Copepods

2. Holoplankton:
Planktonic throughout life
I.e. Rotifers, Claudocerans, Copepods
Meroplankton: Planktonic for part of life-history
I.e. Chaoborus – terrestrial adult stage
Zebra mussel veliger – benthic adult stage

3. Life Cycle of Holoplankton:
Many are parthenogenic

4. Life Cycle of Holoplankton:
Many are parthenogenic
Resting eggs
Rotifers and Cladocerans
only the resting egg comes from sexual reproduction

5. Haploid (all female) eggs
Female (haploid eggs)
Male (haploid gamete)
Diapausing (diploid) egg

6. Cladoceran asexual reproduction

8. Sexual reproduction
Ephippium – modified from the female’s molted carapace

9. Life Cycle of Holoplankton:
Many are parthenogenic
Resting eggs
Rotifers and Cladocerans
only the resting egg comes from sexual reproduction
Copepods –
most eggs come from sexual reproduction
Hatching eggs (embryos) in summer,
resting eggs (embryos) in fall.

11. Nauplius – juvenile copepod

12. Filter feeders (most cladocerans, copepods and rotifers)

13. Filter feeders (most cladocerans, copepods and rotifers)
because size range of particles is large, many have adapted to optimal size via filter feeding

14. Filter feeders (most cladocerans, copepods and rotifers)
because size range of particles is large, many have adapted to optimal size via filter feeding
filter mechanism is composed of hair-like projections, body parts

15. Filter feeders (most cladocerans, copepods and rotifers)
because size range of particles is large, many have adapted to optimal size via filter feeding
filter mechanism is composed of hair-like projections, body parts
Size selection of particles

16. Filter feeders (most cladocerans, copepods and rotifers)
because size range of particles is large, many have adapted to optimal size via filter feeding
filter mechanism is composed of hair-like projections, body parts
Size selection of particles
have special sensory cells on antennae to locate particles

17. Benthic organisms – primarily living on the bottom
Worms
Malacostracans – shrimp, isopods, amphipods, Crayfish
Insects
Macroinvertebrates

18. Worms = Annelida
Leeches and Oligiochaetes
Chironomids are NOT worms

19. Leeches
Worm-like with distinct head
Parasitic

20. Sexual reproduction
Hermaphodites

22. Head nearly indistinguishable from tail
Oligeocheate worms
Segmented
Head nearly indistinguishable from tail

23. Most relatively tolerant of organic pollution Omnivorous
Many are burrowers
FIG Comparison of the distribution of the oligochaete Limnodrilus cervix over
the study period at all sites.

24. Fertilization occurs externally in a cocoon secreted by the clitellum
Reproduction
Hermaphroditic
Sperm exchanged then stored in spermatheca

26. Amphipods
Omnivores
Sexual reproduction
Amphipod eggs
Short distance swimmers

27. Isopods
Omnivores
Some parasitic

28. Sexual reproduction
Female carries eggs under the abdomen until they hatch
Mostly live on benthos but swim short distances

29. Crayfish

30. Sexual reproduction: The fertilised eggs are attached to the female' swimmerets on the underside of her jointed abdomen.
10 to 800 eggs that change from dark to translucent as they develop
Nocturnal
Omnivorous

32. Spread by bait buckets

33. Outcompete native crayfish (produce 80-575 eggs/year)
Compete with juvenile fish for invertebrate prey
Consume large quantities of aquatic plants – thereby reducing cover for juvenile fish
“Rusty” crayfish have an extremely high metabolic rate