Marine biology Flashcards
What are the 3 modes of life in the sea?
- Pelagic
- Shifting & Ephermal
- Plankton - drift
- Nekton - swim - Benthic/demersal (bottom)
How do pleagia maintain buoyancy?
Through spines/hairs, trailing threads, flattened body, inclusion of oils/fats and gas chambers
Give 4 examples of plankton
- larvae
- cnidarians such as jellyfish
- zooplankton
- phytoplankton
Give 4 examples of nekton
- bony fish
- elasmobranchs (sharks and rays)
- marine mammals
- cephalopods (octopi and squid)
What is a characteristic of benthic dwellers?
Often have attachments to the surface
What are interface animals?
Animals that exploit the interface between the sea and the air, often have sail appendages for dispersal
What are porifera?
Parazoa (sponges) refers to ostia (pores)
Circulate water via special cells, and are the most primitive of marine multi-cellular organisms
Describe the anatomy of the eumatazoa/cnidarians
- Radially symmetrical
- Diploblastic (2 types of tissue)
- Mesoglea is invaginated between endoderm (making the enteron/gut) and ectoderm
- Has an incomplete digestive tract
- stinging cells (nematocysts) on marginal tentacles
What are the 3 main body parts of molluscs?
- Muscular foot
- Visceral mass
- Mantle
What are the 4 types of molluscs (with examples)?
- Bivalves (2 shells) - clams, oysters
- Gastropods (single shell) - sea snail
- Polyplacophoran - chitons
- Cephalopods - octopus, squid, cuttlefish
What are 3 features of anthropods?
- segmented bodies
- jointed appendages
- exoskeleton
Name 6 features of echinoderms
- Spiny skin
- Radial anatomy
- Pentamorous (5 parts)
- Water vascular system
- Endoskeleton
- Tube feet
What are the features that must be present in chordates?
NOT NECESSARILY A SPINE
- Dorsal, hollow nerve chord
- Notochord
- Pharygeal slits
- Post anal tail
What are the 2 types of cnidarians?
Polyps - sat on the ground with mouth up
Medusa - swimming with mouth down
What are the 2 types of polyps?
Hard case - calcified skeleton provide protection and support, live individually
Soft case - proteinaceous case and live colonially
How do adaptations for swimming differ with body size?
smaller - need to maintain buoyancy therefore high surface area
larger - inertia, torpedo shapes
What are the advantages of burrowing?
Good for responding t osmotic/thermal/respiratory stress
Describe the mechanism echinoderms use to move
- Central ring canal extends out into radial canal
- Water flows through radial canal, into lateral canal and ampullae which then contracts
- Causes extension in tube feet
What are passive suspension feeders?
animals that expose a large surface area to currents to feed on suspended particles using cilia/filtration/sticky mucus
How are sponges active suspension feeders?
- Actively generate currents using flagella to force water out of the osculum and in through the ostia
- Food trapped by the flagella flows down the collar into the cell body
What are deposit feeders?
- Feed on sediment of microalgae and particulate organic matter
- Either at surface or under sediment
What are the advantages and disadvantages of internal fertilisation?
- Higher chance of fertilisation
- Lower chance of finding a mate
What are the advantages and disadvantages of external fertilisation?
- Do not have to find a mate
- Gametes at risk of predation and dilutiojn
Which 5 ways can improve the odds of external fertilisation?
- Ensuring sperm transfer
- Volume of gametes
- Reduce distance between sexes
- Minimal water turbulance
- Gamete behaviour (active swimming)
- Timing
Describe gonochoristic fertilisation
- Form aggreagations and take up spawning posture
- One individual releases spawning hormone triggering spawn of all other individuals
Give an example of a simultaneous hermaphrodite
Aplysia (sea hare) forms mating chains either laying eggs or depositing sperm alternatively
What are protandrous hermaphrodites?
Male first
Explain the mating systems of
a) Crepidula fornicata
b) Amphiprion ocellaris
a) form a stack where bottom most male becomes female
b) oldest and largest male becomes the female
What are the 3 different reproductive systems of crustanceans?
- Simultaneous hemaphrodites
- Androdioecy - hemaphrodites and dwarf males
- Dioecy - females and dwarf males
How do barnacles reproduce?
Female barnacle broods eggs which released as cyprid larvae which metamorphose head down on a suitable surface
What are the 3 methods of asexual reproduction?
- Fission - one idividual separates into 2 individuals
- Budding - new organism growing off the original organism
- Fragmentation (pedal laceration) - New organism forms off fragment of parent
