Survival Flashcards
What are the main problems animals must solve the survive?
1) Get food and oxygen
2) Maintenance of water and salt balance
3) Removal of waste
4) Reproduction
What can the body design of an animal be affected by?
The environment
Size of the animal
The mode of existence
What are some of the zones found in a marine environment?
Photic zone - where light can penetrate (up to ~200m) and phytoplankton can photosynthesise
Neritic zone - Over the continental shelf
Littoral - beach zone
Eulittoral zone aka intertidal zone - area between low and high zone
Name some animals often found in the intertidal zone
Barnacles
Sea anemone
What type of reefs are found on the continental shelf?
Fringing reefs
What type of sponge is found in the deep sea? What unusal behaviour does it exhibit?
Harp sponge
Evolved to become a predator, carnivourous behaviour is usual for sponges
What is the deepest area of the oceans?
The abyssal plain
However, trenches can go deeper than the plain e.g. the Mariana Trench
What does pelagic mean?
Suspended or swimming in water
What does benthic mean?
Bottom
What are the different ways marine animals can live? Give a brief definition of what they mean
Errant = mobile/active
Sessile = attached
Sedentary = unattached but imobile
What are the advanatges of living in the sea?
Space - means there is large amounts of productivity
Often constant temperature (due to high SHC, salinity, oxygen and pH
What does buoyancy allow for?
Increase in the size of organisms
What do marine animals secrete as waste?
Ammonia as it is very soluble in water - therefore do not need to change it into a less toxic byproduct like terrestrial organisms
Give the two indirect life cycles? What causes the difference?
Little egg yolk:
Free spawning
Plankotrophic free-swimming larvae
Settlement and metamorphosis
Juveniles
Maturation
Weakly isolecithal ova
More Egg Yolk:
Free spawning
Lecithotrophic free-swimming larvae
Settlement and metamorphosis
Juveniles
Maturation
Moderately to strongly telolecithal ova
Give the direct lifecycle
Mating
Brooding or encapsulation of embryos
Hatching as juveniles
Maturation
Strongly telolecithal ova
Give the mixed lifecycle
Mating
Brooding or encapsualtion of embryos
Hatching as free-swimming larvae
Settlement and metamorphosis
Juveniles
Maturation
Moderately telolethical ova
When are direct and mixed lifecycles more common? Why?
More common in freshwater
Osmoregulation may be required for eggs/sperm in freshwater
What are estuarine life cycles dependent on?
The organism
Can be indirect, direct or mixed
What has evolved for organisms depending on their mode of existence?
Free-moving - bilateral symmetry and cephalisation (concentration of sense organs at the anterior end of the body which forms the head and brain)
Attached/sedentary - radial symmetry or asymmetry
