Marine Bio quiz

Chapter 13

What is reproduction?

  • Reproduction without sex: ciliate cell division
  • w/o sex → genetically identical
  • Clonal growth + fission budding eggs that develop without fertilization
  • Creation of new individuals = essential for growth maintenance of population

Sexual reproduction

  • 2 sets of gametes combine to form a new individual

Costs of sexual reproduction

  • Asexual: After 2 generations, the female has made 4 new females
  • Sexual reproduction- the twofold cost
  • Female spends 50% of her energy producing male offspring
  • Male offspring is unable to produce offspring by itself
  • After 2 generations, the female has made 1 new female
  • Additional costs → finding new mates, sexual selection

Benefits of sexual reproduction

  • Sexual reproduction: New phenotypes w/o mutations, increase in diversity, faster
  • Genetic diversity:

- Resilience to environmental variability

- resistance to disease

- fills new niches

- prevents prevalence of recessive diseases

Equal exchange + unequal exchange

  • Recombination
  • Not always 50-50

Sexual selection (vs. natural selection) - polymorphism

  • Sexual selection: selection for traits that increase mating success, by males by conspecific competition (not always beneficial to survival)
  • Natural selection: Fitness, “best fit” survive + reproduce and become dominant.
  • Polymorphism: Physical differences between species
  • Ex. Elephant seals are 3x larger than females and use their size and strength to defend harems, ensuring their genes are passed on
  • Ex. Fiddler crab males use large claw display to attract females and for combat with other males

Sometimes the male is the primary parent!

  • Ex. Seahorses

Types of sexuality found in marine organisms

  • Gonochoristic - “typical” separate sexes in separate individuals
  • Hermaphroditic - 1 individual can have both MBF sex organs
  • Simultaneous - M+F same time
  • Sequential - one then the other in lifetime

- Protandrous - Male then Female (clownfish)

- Protogynous - Female then Male (wrasse)

Eusociality- Queen, males, immatures

  • Colonies with cooperative core + many generations
  • Ex. Synalpheus species- snapping shrimp
  • Altruistic behavior

- Kin selection

- helping relatives to ensure some genes passed

Life History Theory- K vs r selection

  • How many offspring + how fast they mature
  • R selected (type III) - High reproductive rate, low paternal investment, mature earlier, relatively short lived
  • Insects, rodents, plants
  • K selected - survivorship + growth rate

- Low reproductive rate + high paternal investment

- larger and longer lived

- specialized niche

- Elephants, humans, whales

Migration vs dispersal

  • Directional between specific sites
  • Adult stock
  • Spawning area
  • Nursery area

Migration types

  • Some species migrate between fresh and salt water (“diadromus”)
  • Anadromous: Most of life in ocean but breed in freshwater (ex. salmon)
  • Catadromous: spent most of life in freshwater or tidal creeks but breed in the ocean (Ex. Anguilla eels)
  • Fully oceanic - herring, green turtle, humpback whale
  • Specificity of site varies
  • Ex. Tagging locations, Pacific white shark, Carcharodan carcharias
  • Ex. Humpback whale, Megaptera

Dispersal types

  • Direct release - close by → release/ lay fever eggs + more paternal investment
  • Lecithotrophic larvae - dispersed by H2O but short distances → larvae don't need to feed during
  • Planktotrophic larvae - feed + locomote during dispersal

Larval types

  • Lecithotrophic larva: tadpole larva of the colonial ascidian Botryllus schloesseri
  • Planktotrophic larva of snail Cymatium Parthenopetum
  • Planktotrophic pluteus larvae of an urchin

General patterns of larval movement relative to the coastline

Tidal estuaries have two unique patterns for larval recruitment

  • Coastal migration and return - reduce predation risk
  • Estuarine retention- feeding

Estuarine retention

  • Mud crab: Rhithropanopeus harrisii
  • Larvae rise on the flooding tide, sink to bottom on the ebbing tide: results in retention of larvae within estuary Larvae defended against predation by erectile spines

Move offshore to return when larger

Chapter 14: The open sea, processes and Productivity in the water column

The open ocean

  • Pelagic ecosystem, in which living components are plankton and nekton
  • Consists of the portion of the ocean above the bottom, deeper/away from the neritic zone (coasts)

The role of light

  • Photic zone: where light reaches and phytoplankton survive
  • Aphotic zone: area with no light and no phytoplankton survive

Patchiness of plankton in the open ocean

Due to:

  • Upwelling
  • Sea surface variations
  • Vertical mixing
  • Downwelling
  • Predator presence
  • Diurnal movement - day vs night

Water currents can aggregate plankton

  1. Langmuir circulation converges (on surface)
  2. Circulation around an island
  3. Tidal current exiting a constriction at the mouth of an estuary

Chapter 11 Interlude: Phytoplankton seasonal changes

Phytoplankton seasonal changes- often bloom in spring

  • Svendrop model
  • Mixing depth
  • Critical depth - comparison of O2 produced vs. consumed
  • If mixing depth is greater than critical depth = no bloom if mixing depth is less than critical = bloom increase in phytoplankton population

Svendrop model

  • Sometimes populations bloom while H2O is odd + mixed

Behrenfeld alternative model

  • Maybe reduced pressure from predators is also a main driver of blooms

Phytoplankton seasonal changes

  • During summer nutrients used + settle out in fall they’re mixed in an accesside again

Effect of latitude

Artic

  • Short burst in summer
  • Followed by zooplankton
  • Similar to spring in temperature
  • Tropics- no pattern

Nutrient exchange between water column and benthos

  • Shallow water can always do exchange
  • Exchange b/c of mixing - fall/winter

Ecology of open sea

  • Pelagic ecosystem
  • Productivity based on plankton
  • Light near the surface, but few nutrients
  • 1 Degree- Photosynthesizing is the in water column
  • 2 degree- secondary productivity - organisms that consume primary producers

Primary productivity measurements

  • Measure wavelengths of light reflected vs absorbed by chlorophyll - needs local ground

Application to climate change

  • Sea surface temperature
  • Net primary productivity
  • Increase temp
  • Decrease wind driven mixing
  • Increase stratification
  • Decrease primary productivity

Food chain abstraction

  • Linear sequence
  • sequence/series of trophic levels

Transfer between trophic levels

  • Budget for ingested food (energy units):
  • I = E + R + G - tissues of organisms, can pass it up the food chain
  • I = amount ingested
  • E = amount egested (loss) - feces + urine + heat
  • R = Amount respired (loss)
  • G = growth (partitioned between somatic growth and reproduction) (gain)
  • Efficiency = amount extracted (put into G)/ amount that was supplied (I)

Incomplete transfer up a food chain:

  • Measure by food chain efficiency:
  • E = amount extracted from a trophic level/ amount of energy supplied to that level
  • E can also be as little as 10%, but as much as 50%

Food chain efficiency

P=BEn

  • P = production of the highest level
  • B = Primary production
  • E= food chain efficient
  • n = # of links in the system

Productivity that can go to the top of a chain depends on primary efficiency of levels

Food chain structure determination

  • Food chain dictated by predator presence
  • Dictated by amount of primary production

Descending to the depths

  • Some phyto sink below photic zone when they die → organic material for other 1 degree producers