[Jul 30th, 2015] – Lectures, Seminars (Team Round-headed Apple Borer)
Blog Entry Written by Team: Round-headed Apple Borer
Team Members: Jacqueline Chiu (U of T), Joshua Boateng (Trent U), Yunhui Zhou (Fudan), Yeqi Lin (SW).
Weather: Sunny, Temp: 20-28℃.
Today was filled with many seminars and lectures and so we were indoors all day. We started the day with Dr. Wang’s lecture on Fish Biodiversity and Conservation. We learned about the origins of fish including the fact that fish are the first vertebrates in history. We learned about two species of jawless fish, which are hagfish (Myxiniforms spp.) and lamprey (Lampetra spp.). Here are some facts about the hagfish and the lamprey species:
|~60 species, eyes covered with thick skin, lack paired fins, predator & scavenger.||~40 species, pre-longed larval period with multiple life stages, parasite to fish, eggs buried in sediment, spawn in freshwater, migrate to seawater, 75-100 cm, sectorial disc teeth, lack paired fins.|
Lamprey can be an invasive species, so people have adopted several methods to control this including:
-building dams to block the lamprey
-using chemicals to kill the lamprey
-using pheromones to attract males and sterilize them and then put them back into the ecosystem; this prevents the males from being able to spread their sperm, which in turn helps decrease the population.
But strictly speaking, jawless fish is not a “fish”, though they usually have a fish-like body shape. The hagfish and lamprey we mentioned above actually belongs to the class Cyclostomata, which does not include the fish we commonly refer to.
The next topic was about jawed fish, which is split up into two categories, bony fishes (Teleostomi), in which 41% are freshwater fish, and cartilaginous fish (Chondrichthyes). Dr. Wang mainly focused on bony fishes. The structures of the fish correspond to specific functions. They have gills for gas exchange, ion regulation, acid-base regulation, filtering water and excreting nitrogen waste. They also have a complex skull to allow feeding, respiration and sensation. Their skeleton and muscles are mainly focused in the trunk of the fish body.
The next lecture presented by Dr. Wang was about his past and current research on Comparative Physiology. Dr. Wang mentioned that he did his research on non-lab animals which means that he always brought the lab to where the species were located as opposed to having the species brought into a lab. This ensured that the species were in their natural environment. Another key point that Dr. Wang mentioned was that morphology reflects functionality. He talked about fishes he encountered during the period of his research including Pirarucu (Arapaima gigas), Oscar (Astronotus ocellatus), Armoured catfish (Pterygoplichthys multiradiatus) and Naked carp (Gymnocypris przewalski). Here are some further details about each fish:
|Species of Fish||Features|
|Pirarucu||l 2-3 m in size
l Obligated air-breather, use bladder to retrieve O2
l Deformed gills, remove CO2 through the gills
l Extraordinary kidney
|Oscar||l Have a bright spot on the tail to trick predators and increase their chance of survival
l Can tolerate 0.3 mg/L of O2 at 30 degree Celsius
l Can tolerate the daily fluctuation of O2 (0.3- 9 mg/L)
l Can shut down one gill to slow down metabolism and conserve energy
|Armoured catfish||l Can tolerate extreme hypercapnia and acid-base disturbance
l Do not regulate extracellular pH
l Hemoglobin does not display the Root effect
|Naked carp||l No scales
l Slow growth (300 g/10 year)
l Migrates to freshwater for spawning (anadromous)
l Not stenohaline (can tolerate a large fluctuation in the salinity of water)
l Hypoxic tolerant (can tolerate low levels of O2)
Since all these fish have swim bladders, they all experience the Root Effect which is a physiological phenomenon that occurs in fish hemoglobin where with an increased H+ or CO2 concentration, hemoglobin’s affinity and carrying capacity for oxygen decreases.
In the afternoon, we had four student seminars. The topics we talked about include Climate Change, Invasive Species, Eutrophication and Dams. We were one of the groups to present and our topic was Eutrophication. Eutrophication is a natural phenomenon that occurs in an aging lake or pond where nutrients that enter the bodies of water feed the algae causing excessive growth of the algae. Eventually, the algae have to compete for resources and nutrients and some die off, decaying and settling to the bottom of the body of water, decreasing the size of the water body. Our day ended after the student seminars.
l 只能在空气中呼吸, 从鱼鳔中获取O2，从鱼鳃中排出CO2。
l 可以忍受极低的氧含量(0.3mg/L, 30摄氏度)。
l 可以忍受氧含量的大幅波动O2 (0.3- 9 mg/L)。
|Armoured catfish||l 可以忍受血液中高浓度的CO2，和体内pH严重偏离。
l 血红蛋白不会有Root effct
|Naked carp||l 无鳞鱼。
l 生长缓慢(300 g/10年)。