Ch2 Physiological Adaptations, Reproduction, and Larval Transport

What is the difference between a regulator and a conformer?

A regulator maintains internal physiological conditions (temperature, ion concentration, etc.) within a narrow range despite environmental fluctuations, expending energy to do so. A conformer's internal conditions match (track) the surrounding environment, saving energy but limiting habitat range. MarineBio_Ch2_Organisms Slide2

Define scope for growth and give its formula.

The energy available for growth and reproduction after meeting maintenance costs. Scope for growth = energy consumed (assimilated) − basal metabolic rate. Acclimation temperature, ration, and stress all shift it. MarineBio_Ch2_Organisms Slide3

What shape is the typical mortality-rate vs. test-temperature curve, and why?

A U-shape: mortality rises at both temperature extremes, with a broad survival minimum near the species' optimum. Cold extremes disrupt enzyme kinetics/membrane fluidity; hot extremes cause oxygen-delivery failure and protein denaturation. MarineBio_Ch2_Organisms Slide4

Compare homeotherms and poikilotherms.

Homeotherms maintain a relatively constant body temperature regardless of ambient temperature (most birds and mammals). Poikilotherms have body temperatures that vary with the environment (most fish, invertebrates, reptiles). MarineBio_Ch2_Organisms Slide5

What is a countercurrent heat exchanger and what does it accomplish?

A vascular arrangement in which warm outgoing arterial blood runs alongside cold incoming venous blood, transferring heat between them. It conserves core body heat (e.g., in tuna red muscle, marine mammal flippers) by preventing heat loss to cold extremities or surrounding water. MarineBio_Ch2_Organisms Slide5

What is Q₁₀, and what is the typical biological value?

The temperature coefficient — the factor by which metabolic rate changes for a 10 °C rise in temperature. Q₁₀ = (MR at T₂) / (MR at T₁) for a 10 °C interval. Most biological reactions have Q₁₀ ≈ 2-3. MarineBio_Ch2_Organisms Slide6

What are isozymes and how do they help organisms acclimate to temperature change?

Different molecular forms of an enzyme that catalyze the same reaction but have different temperature optima. Organisms can express different isozymes seasonally (or after acclimation) to maintain stable metabolic rates as temperature shifts. MarineBio_Ch2_Organisms Slide7

What are heat shock proteins (HSPs) and what do they do?

Molecular chaperones produced in response to thermal stress (and other stressors). They bind misfolded proteins, refold them, or target them for degradation, protecting the cell from heat damage. MarineBio_Ch2_Organisms Slide8

What is homeoviscous adaptation?

The adjustment of membrane lipid composition (ratio of saturated to unsaturated fatty acids) to maintain proper membrane fluidity across temperatures. Cold-acclimated organisms incorporate more unsaturated fatty acids to keep membranes fluid; heat-acclimated organisms do the opposite. MarineBio_Ch2_Organisms Slide8

How do antifreeze glycoproteins protect polar fish from freezing?

They bind to the surface of small ice crystals and block further water molecules from joining the lattice, lowering the freezing point of body fluids non-colligatively (without disturbing osmotic balance). MarineBio_Ch2_Organisms Slide8

Distinguish hyperosmotic and hypoosmotic (with respect to seawater).

Hyperosmotic = body fluids more concentrated (saltier) than the surroundings → water flows IN by osmosis (e.g., freshwater fish vs. their water). Hypoosmotic = body fluids less concentrated than surroundings → water flows OUT (e.g., marine bony fish vs. seawater). MarineBio_Ch2_Organisms Slide10

What is the difference between an osmoconformer and an osmoregulator? Give marine examples of each.

Osmoconformers let internal osmolarity match seawater (e.g., most marine invertebrates, hagfish, elasmobranchs). Osmoregulators actively maintain internal osmolarity different from the environment (e.g., marine bony fish, which are hypoosmotic regulators). Note: a hagfish is both an osmoconformer AND an ionoconformer; sharks are osmoconformers but ionoregulators. MarineBio_Ch2_Organisms Slide10-11

What are organic osmolytes, and name three classes used by marine animals.

Small organic solutes accumulated intracellularly to balance external osmotic pressure without disrupting protein function. Examples: free amino acids, urea, and methylamines (e.g., TMAO, which counteracts urea's destabilizing effects in elasmobranchs). MarineBio_Ch2_Organisms Slide10-11

How does metabolic rate scale with body mass across animals, and what does this mean for small vs. large organisms?

Metabolic rate scales as roughly mass^0.75 — total metabolism rises with size, but mass-specific (per-gram) metabolic rate FALLS with size. Small organisms have higher per-gram oxygen demand; very small ones can rely on diffusion alone, while large organisms require dedicated circulatory and respiratory systems. MarineBio_Ch2_Organisms Slide12

Name the five major respiratory pigments and the metal each uses.

Hemocyanin (Cu, highly variable size); hemerythrin (Fe, non-porphyrin, small); chlorocruorin (Fe, porphyrin, very large); hemoglobin (Fe, porphyrin, highly variable); myoglobin (Fe, porphyrin, small, intracellular muscle storage). MarineBio_Ch2_Organisms Slide14

What is the Bohr shift on an oxygen dissociation curve?

A rightward shift of the hemoglobin O₂-saturation curve caused by lower pH (or higher CO₂/temperature), which DECREASES O₂ affinity. This unloads more oxygen in metabolically active tissues where CO₂ is high and pH is low. MarineBio_Ch2_Organisms Slide15

Name the three image-forming eye designs in marine animals and which organisms use each.

(1) Pinhole camera — Nautilus (open eye with no lens); (2) lens — fish, squid, lobsters; (3) curved reflector — scallops (a concave mirror behind the retina focuses light). MarineBio_Ch2_Organisms Slide16

What is the Reynolds number and what does a high vs. low value mean?

Re = (Vlρ)/μ, the ratio of inertial to viscous forces (V = velocity, l = characteristic length, ρ = density, μ = viscosity). High Re → inertial forces dominate (turbulent, like a swimming fish); low Re → viscous forces dominate (like a copepod or larva, where water feels "thick" and motion stops as soon as effort stops). MarineBio_Ch2_Organisms Slide18

Give one main benefit and three costs of sexual reproduction.

Benefit: genetic diversity (better response to changing environments, parasites). Costs: maintaining secondary sexual characteristics, intraspecific competition for mates, increased exposure to predation during display/mating, and high female investment in eggs. MarineBio_Ch2_Organisms Slide20

Distinguish intrasexual from intersexual selection, and name three hypotheses for why females prefer certain males.

Intrasexual = competition WITHIN one sex (often males) for access to mates (e.g., leks). Intersexual = mate CHOICE by the other sex, producing sexual dimorphism. Three hypotheses: runaway selection (Fisherian), good genes, and parasite resistance (Hamilton-Zuk). MarineBio_Ch2_Organisms Slide21

Distinguish protandrous from protogynous sequential hermaphrodites; give an example of each.

Protandrous = male first, then female (e.g., clownfish). Protogynous = female first, then male (e.g., many wrasses, parrotfish). Both are sequential hermaphrodites — different from simultaneous hermaphrodites, which are both sexes at once. MarineBio_Ch2_Organisms Slide22

What is polyspermy, why is it a problem, and how do eggs block it?

Polyspermy = fertilization by more than one sperm, which is lethal because it produces too many chromosomes. Eggs block it via a fast block (rapid membrane depolarization) and a slow block (cortical granule release that lifts/hardens the fertilization envelope). Particularly important for broadcast (free) spawners exposed to many sperm. MarineBio_Ch2_Organisms Slide23

Name four modes of asexual reproduction in marine organisms.

Fission (splitting in two, e.g., some anemones); fragmentation (breaking off body pieces that regenerate, e.g., sea stars); modular budding (e.g., colonial cnidarians, ascidians); and reduction bodies (dormant survival propagules in some sponges/bryozoans). MarineBio_Ch2_Organisms Slide25

Distinguish semelparity from iteroparity; give an example of each.

Semelparity = a single, large reproductive event followed by death (e.g., Pacific salmon, octopus). Iteroparity = multiple reproductive events over a lifetime (e.g., most fish, marine mammals). MarineBio_Ch2_Organisms Slide26

Define anadromous and catadromous migration, and give an example of each.

Both are diadromous (migrating between salt and fresh water). Anadromous = adults live in the sea, return to fresh water to spawn (e.g., salmon). Catadromous = adults live in fresh water, migrate to the sea to spawn (e.g., freshwater eels, Anguilla). MarineBio_Ch2_Organisms Slide27

Distinguish lecithotrophic from planktotrophic larvae and the trade-offs between them.

Lecithotrophic = larvae fueled by yolk (do not feed in plankton); typically short pelagic stage, lower dispersal, higher per-larva survival. Planktotrophic = larvae feed on plankton; longer pelagic phase, much greater dispersal, far higher fecundity but high mortality. MarineBio_Ch2_Organisms Slide30

Distinguish oviparity, viviparity, and ovoviviparity.

Oviparity = lays eggs that develop and hatch externally (most fish). Viviparity = embryos develop inside the mother with maternal nutrient transfer, born live (e.g., some sharks, marine mammals). Ovoviviparity = embryos develop in eggs retained inside the mother and hatch internally before birth, but rely on yolk rather than maternal nutrients. MarineBio_Ch2_Organisms Slide30

Match each named larval type to its phylum/group: planula, trochophore, pluteus, nauplius, zoea, veliger.

Planula → Cnidaria; trochophore → annelids and many mollusks; pluteus → echinoderms (sea urchins, brittle stars); nauplius → crustaceans (early stage); zoea → decapod crustaceans (later stage, e.g., crabs); veliger → mollusks (gastropods, bivalves). MarineBio_Ch2_Organisms Slide32

Name the four mesoscale processes that transport larvae onto a coastline.

Wind-driven onshore recruitment, self-seeding eddies, internal waves and tidal bores, and longshore drift. Loss to offshore waters is the counter-process that removes larvae from the shore population. MarineBio_Ch2_Organisms Slide35

How do cyclonic gyres and vertical migration both serve as larval RETENTION mechanisms (rather than dispersal)?

A cyclonic (closed-loop) flow keeps larvae circulating within a region near suitable adult habitat (e.g., Nephrops norvegicus larvae held over the Irish Sea mud patch). Vertical migration lets larvae exploit oppositely flowing water layers (e.g., descending on ebb tide and rising on flood tide) so that net horizontal transport is zero or directed back toward the estuary/coast. MarineBio_Ch2_Organisms Slide36-38