SIO 132- Section 3

lectures 13-18

Fission

Fission

done by many unicellular organisms, asexual reproduction

Binary fission

asexual reproduction by a separation of the body into two new bodies .

an organism duplicates its genetic material, or deoxyribonucleic acid (DNA), and then divides into two parts (cytokinesis), with each new organism receiving one copy of DNA.

includes mitosis

Multiple fission

lots of nuclear replication in a single cell followed by cytokinesis to split into a bunch more cells

Budding

• growth of a whole new organism on the parent like a “tumor”

  • No splitting of the parent

  • Ex. solitary anemones 

• Advantages of asexual reproduction

• Only need yourself, no need to bother with finding and wooing a mate

• Pass on 100% genes to offspring

• Each offspring can also make its own offspring

Disadvantages of sexual reproduction

• Time and energy investment into mate finding, as well as risk from predation etc.

• Pass on half as many genes

• End up making a non-birthing sex (males)

Life Cycle

• the sequence of morphologies and ecologies through which an organism passes from a single cell of one generation to create a single cell of the next generation.

Simple Life Cycle

• direct development, no strong morphological or ecological shifts. Egg → juvenile → adult → egg

  • Any species whose juvenile form looks like a small version of the adult. Like cuttlefish

Complex Life Cycle

• organism abruptly transitions between ecologically and/or morphologically distinct stages. Egg → larva (maybe multiple larva stages) → juvenile → adult → egg

• more common life cycle

metamorphosis

the temporally compressed rebuilding of an organism between stages and those intermediate forms often suck massive ass

Parasitic life cycles

• Two habitats – the “normal” habitats like the ocean bottom or the water column, and the host

• Some end up having complex multi-host life cycles

  • Morphology depends on what hosts they have. Pretty fancy stuff 

colonies

• cloned organisms that stay together and are physically connected. Girls who slay together stay together

division of labor

• individuals in a colony form castes that specialize in certain tasks, like feeding, movement, defense, reproduction

example of division of labor: siphonophores

• Form a chain of a bunch of dudes, and different segments of dudes have different responsibilities, like a group that keeps the colony floating, one that does reproduction, etc.

Inclusive fitness

• an individual’s direct (personal reproductive success) fitness plus their indirect fitness (reproductive success of kin obtained with your help)

  • Ex. sea anemone soldier polyps have high inclusive fitness because they help the other members of the colony reproduce by protecting them despite having no gonads of their own 

symbiosis

long-term living together of two heterospecific individuals. There are different types.

• commensalism (ex.skeleton shrimp)

• an association between two organisms in which one benefits and the other derives neither benefit nor harm

• Usually detritivores or predators, and often live on other organisms for their entire life 

• Probably not feeding on the host, just hitching a ride or staying close to a larger organism for protection, coz the hosts don’t really notice they’re there

• Some are very host-specific

• Ex. of mutualism (or maybe domestication): corals and algae

• Algae receive protection and nutrition from the coral

• Coral receive sugar from algae’s photosynthesis

• Reef building coral get 95% of their nutrition from algae

• Some research thinks that the algae would have better fitness being free-living though so maybe it’s closer to domestication than mutualism

example of mutualism: pom pom crabs

• Claws evolved specifically to hold anemones – can’t do much else

• Can also take food that the anemone catch

• Anemones used to accentuate movements for crab-to-crab interaction (ex. Mating rituals?)

• Unsure if it’s real mutualism because the anemone doesn’t get as many benefits, but it’s not really found away from its crab partners so maybe there’s some benefit we haven’t noticed yet

• Crabs steal anemones from each other, but often they just take parts, so both crabs will still have anemones because the anemones regenerate

• If crabs can only get their hands on one anemone, they’ll just rip it in half so that they can still dual-wield

cleaner evolution

• Conspicuous coloration and behavior

• Set up “cleaning stations”

• Visited by many species of clients

client evolution

• Stereotypical behavior

  • Stop swimming

  • Open their mouths

  • Hold head up or down

  • Feeding restraint

Obligate feeding specialists

• species that evolved specifically to feed off micropredators

  • Ex. cleaner wrasses and gobies

  • Not usually found in the temperate zone 

aggressive mimicry

pretend to be cleaners but are actually micropredators

• harmful species evolving to look like harmless ones in order to attract prey

  • Some pretend to be prey’s food 

    • Ex. Anglerfish and their glowing lures – pretending to be a bioluminescent bacteria, invertebrate, etc

    • Some species of parasites aggregate together to look like a bunch of worms and then feed on whatever eats them

Batesian mimicry

• a harmless species disguises itself as a harmful one to avoid predators

  • Model other species that are toxic, or just evolve bright colors to signal toxicity

  • Dynamic batesian mimicry: ability to change shape and colors spontaneously

    • Ex. mimic octopus that can observe things in its environment and then change its movement and behavior to look like things that are harmful, like grouping their arms together in two directions to look like a sea snake. Smart cookie!!

Mullerian mimicry

• two or more harmful species evolving to resemble one another to maximize predator avoidance

Social mimicry

• similar but unrelated species schooling together for protection (since predators tend to hone in on any individual that sticks out from the group)

ecology

the study of the distribution and abundance of organisms, including causes and consequences. Has a hierarchy of sub-topics

autecology

• the ecological study of an individual organism, or sometimes a particular species

• single species, individual based

population ecology

• dynamics of a single population

community ecology

• studying more than one species

  • Interaction ecology: considers all sides of 2 or 3 species’ interactions

  • Assemblages

  • Food web ecology

ecosystem ecology

• adds in the abiotic environment – inputs, outputs, energy, minerals

ecological niche

• the environmental requirements of a species to have greater birth than death rates along with the effects of the species on those environmental conditions

fundamental niche

• the set of environmental requirements permitting species to persist

realized niche

• the area to which a species is restricted 

interspecific competition

• different species contending for the same limited resources

  • Niche overlap

  • Negative influence on each other’s populations

exploitation competition

• occurs via reducing resource supply (more common)

interference competition

• occurs via physical interaction between competitors

Important example of competition (specifically for space)

• foundational ecological research done on barnacles in the rocky intertidal

  • Chthamalus and semibalanus – share larval habitats, but not adult habitats. Chthamalus lives higher up than semibalanus 

    • Determined that chthamalus can live down low, but semibalanus outcompetes them

    • Also determined that chthamalus doesn’t outcompete semibalanus up high, but semibalanus die from the abiotic factors of that environment

biogeography

• study of the distribution of species and ecosystems in geographic space and through (geological) time

  • Completely fits within the definition of ecology, but focuses on history and geographic location

LDG (latitudinal diversity gradient)

• pattern that says there is a greater diversity of species in the tropics than temperate and polar regions

  • One of the most pronounced and pervasive patterns we know 

  • Diversity decreases as you head from the equator to the poles

• East atlantic latitudinal diversity data 

• Mediterranean hot spot – causes the peak on latitudinal diversity data

• Sahara upwelling – plummet after the mediterranean hot spot due to upwelling of colder waters from the deep ocean

West atlantic latitudinal diversity data

• Caribbean hot spot causes the peak in the west atlantic

• Giant mudbank deposited by the Amazon river causes the drop afterwards (chokes out diverse fauna and flora you’d normally get with coral reefs, etc., blocks caribbean fauna)

Taxon origination rates (speciation rates)

Warmer water → higher scope for growth → more reproduction → more chances to mutate, more chance for those mutated offspring to survive

Thought to be higher in the tropics.

-Warmer water has been shown to lead to higher mutation rates, species interaction rates, organisms move faster on an individual level.

-Diversity is also higher in warmer waters, even at the same latitudes

Taxon extinction rates

Might be lower in the tropics, meaning that even if every region has the same speciation rates, the tropics will retain more of those species, making them more diverse.

“Out of the tropics” (OTT) model

• Species start in the tropics, and then immigrate to other latitudes

  • Synthetic model that combines the previous two ideas and the idea of the tropics being an immigration pump 

  • Also showed lower extinction rates in the tropics

  • Also found that a large percentage of extratropical bivalves originated in the tropics

Marine biogeographic realms

• Areas with distinct biota have groups of species with shared/congruent evolutionary history 

• Also based on factors that control what kind of species can live in an area

• Creation of biogeographic provinces based on endemism

Marine “centers of origin”

Indo-pacific(mad coral diversity), caribbean, noth pacific, anarctic

fossil

any sign of a life form from a past geological age

body fossils

• preserved remains of a body/cell, usually lithified in some way. Casts and molds are also considered this

trace fossils

traces of an organism’s activity, like footprints, tracks, burrows, teeth marks, nests, etc.

chemical fossils

• biogenic chemicals left behind

Ediacaran fauna

• 640-540 mil years ago

  • Just before phanerozoic 

  • First large animals

  • Simple organization, no hard parts

  • Mostly epifaunal, not too many erect (sticking up tall… it was flat fuck friday)

  • Sessile and slow

  • Lots of deposit feeders

cambrian explosion

• 540 mya

  • Most modern phyla appear around this time, but also a lot of them have gone extinct oops

  • Hard parts

  • More burrowers

  • First pelagic animals

  • Some fast animals, more typical hunting predators

Escalation

• trend for predation and defenses against predation directionally evolving to become more intense and well-developed 

  • Ex. snails developing really spiny shells

Mesozoic marine reptiles

• one post-extinction group that thrived

  • At least 12 separate events/taxa

  • All air breathers

Sauropterygia

• Semi aquatic to fully aquatic organisms. Few different groups

• Placodonts – rigid body, webbed feet, strong teeth (looks like a fat turtle lizard combo)

• Plesiosaurs – come in two major morphs (one with a long neck and one with a long skull)

Ichthyopterygia

• All predators

• Most extremely adapted to the aquatic lifestyle

• Lizard like → dolphin like bodies

• No neck

• Streamlined body shapes

• Paddles → fins

• Shelf dwelling → ocean dwelling

• Big ol eyes relative to their body size for detecting prey in low-light conditions

• Mosasauridae

snakelike body with a large skull and a long snout. Their limbs were modified into paddles having shorter limb bones and more numerous finger and toe bones than those of their ancestors.

Chelonioidea

a family of typically large marine turtles that are characterised by their common traits such as, having a flat streamlined wide and rounded shell and almost paddle-like flippers for their forelimbs. They are the only sea turtles to have stronger front limbs than back limbs.

fisheries

the manipulation of aquatic organisms, aquatic environments, and their human users to produce sustained and ever-increasing benefits for people

Organisms in regards to fisheries

• Targeted species – the species the fishery intends to harvest, generally have high value, are landed (kept once caught)

• Non-targeted catch – not intended target species, but still valuable, so still landed

• Bycatch – not intended target species, low value, discarded (sometimes released but discarded is a broader term since they do die sometimes)

Trophic cascades

• when predators limit the density and/or behavior of their prey and thereby enhance survival of the next lower trophic level. (ex. Overhunting otters and allowing urchin populations to spiral out of control and kill off kelp)

Commercial fishery

• specifically fishing to sell catches

  • Usually large boats that can cover large distances and store a lot of biomass

  • High yields

  • For-profit

  • Feeds many

artisanal fishery

• catching for sale, but on a smaller scale

  • Small boats that cover short distances and can’t carry as much

  • Per vessel yield is low, but overall yield can be high

  • For-profit

  • Feeds many – used to feed the local community and families, excess is sold 

  • Typically done in developing countries

recreational fishery

• very small-scale, fishing for fun

  • Very small boats or no boats at all

  • Per fisher yield is low

  • May feed some if you keep what you catch

Subsistence/traditional fishery

• specifically feeding the fishers and their communities

  • Small scale

  • Low yield

  • Fishing for food – if they don’t catch anything, they miss out on a major source of sustenance

  • Not selling excess globally like artisanal fisheries

  • Might have been sustainable in the past but some fisheries have become unsustainable because of outside environmental impacts humans have had on marine life populations

Types of fishery equipment

• Pole and line – low bycatch

• Longline fishing – big ol rope (28 miles on average) with a bunch of hooks hanging off of it that’s attached to the boat. High bycatch coz it’s huge and often left hanging out for a full day

• Gill net – 1-2 mile long nets left out for hours. Can be set or drifted. High bycatch for obvious reasons

• Purse seine net – thousands of feet long, hundreds of feet deep, cast in a cylindrical sort of shape. When the net is closed, the bottom joins together and it turns into more like a sphere that captures whatever was inside. Typically cast around schools but still has potential for bycatch (ex. If dolphins are hanging around a school of tuna that they’re preying on and get caught in the net)

• Trawl nets – nets attached to the back of a vessel that are dragged either along the sea bed or midwater. High bycatch and potential for habitat destruction (for sea bed trawls especially) 

• Traps/pots – baited traps left on the sea bed generally used to catch bottom dwelling fish, lobsters, and crabs. Medium potential for bycatch (even potential for bycatch of larger marine mammals since all the traps are attached to a line on the boat, which they can get tangled in and eventually die). Can be small-scale or in huge quantities

• Harpoon – literally just a gun. Low bycatch. Often used for swordfish.

Fish stock

• loosely, a population, but can be defined by reproductive isolation, ecological separation, management boundary, fishery range

Stock assessment

• estimating a population size

leading edge

the front that is leading the directional shift in a species range (having the most advanced position)

trailing edge

the area where the populations stay despite climate change

marine reptiles

sea turtles(persisted), marine iguana, sea snakes, sea kraits

thermal pollution

what is this an example of?

a factory that uses water for cooling then releases warm water back into a natural body of water without treating it first

solid pollution

what is this an example of?

plastic water bottles (plastic waste)

chemical pollution

what is this an example of?

oil spills