ZOO 4910 Lecture Notes - Lecture 4: European Perch, Tide Pool, Cardiac Output
2 May 2018
School
Department
Course
Professor
Environmental challenges -temperature, oxygen, salinity, pressure
•
Habitat loss -Aestivation and diapause
•
Extreme cold -living in a frozen world
•
Adaptations of Aquatic Environments:
Increased metabolic rate
○
Increase heart rate
○
Similar cardiac output
○
Decrease heart size
○
Resting adaptations for chronically warmed:
•
*see slide with figures
•
Energy Conservation: chronically warm-adapted perch have
an intrinsically lower heart rate (at same temperatures as the
reference perch)
1.
Upper Limits: maximum temperatures tolerated is similar
between groups (=genetic plateau)
2.
Findings:
•
Study: European perch acclimatized for 3 generations to higher water
temperatures
Large gills
!
Low Hb-O2 P50
!
Low routine O2 consumption
!
Fish that are adapted to hypoxia conditions will have a Pcrit
shifted to the left:
○
Measure of tolerance to hypoxia = Pcrit
•
Tidepool species have a lower Pcrit compared to shallow
water species
○
Gill surface area is greater in more hypoxia tolerant species
○
Oxygen turnover rates are increased in more hypoxia tolerant
species
○
Routine metabolic rates are reduced in more hypoxia tolerant
sculpins
•
Some species will come up to the surface and role around to pick
up oxygen (and may even have emergence behaviour)
•
Study: Hypoxia Challenges in Fish
Actively takes up ions through gills
○
Absorbs water through skin
○
Excretes dilute urine
○
Freshwater environment -fish body is hyper-osmotic
•
Excretes ions through gills
○
Loses water through skin
○
Excretes concentrated urine
○
Saltwater environment -fish body is hypo-osmotic
•
Kidney: decrease in number of glomeruli
○
Intestines: increase permeability to water
○
Silvering and increase in body length (vs body mass)
○
Increase number of teeth
○
Increase chloride cells in gills
○
Increase gap junctions
○
Increase & decrease in gene expression levels
○
Decrease mucus
!
Increase columnar epithelium (impermeable to water)
!
Change in oesophagus:
○
Parr --> Smolt (transformations to changing environment to
conserve water)
•
Challenges of Osmoregulation in Freshwater and Saltwater:
Extreme pressure
○
Lack of oxygen
○
Extreme cold
○
Low food abundance
○
Low density of conspecifics
○
Electroreception?
○
Bioluminescence?
○
Challenges:
•
Lower metabolic rates
○
Solution:
•
Increased use of polyunsaturated lipids in lipid membranes
○
Causes an increase in osmolality (not as hypo-osmotic;
less energy to maintain ionic balance)
!
Increasing levels of TMAO (trimethyl amine oxide) in
tissues -acts as protein chaperone
○
Protein ratios changes
○
Decreasing production of urea
○
Maintaining body shape and protein functions:
•
Found below 6000-800m depths
○
Reduced levels of proteins and other components
found in white muscle
!
Acts as a shock absorber
!
Have specialized jelly tissue (high water content)
○
Ex. Hadal Snailfish
•
Under Pressure: Living in the Deep
They have adapted by using diapause stages during
embryonic development to delay the emergence (after
hatching) of young into a new aquatic environment
○
Diapause I-III
□
Diapause Embryo -production results in arrest in
diapause
!
Escape Embryo -production results in direct
development sand possible hatching
!
Four stages of development:
○
Main characteristic of all diapause stages is a reduction of
embryonic metabolic rates
○
Period Length Triggers
Diapause I days Intrinsic (genetic)
Diapause
II
Months-
years
Increased daylight
•
Fluctuating
temperature
•
Fluctuating O2
•
Rehydration of
perivitelline space
•
Rapid changes in abiotic
factors:
Diapause
III
Up to 4
months
Depletion of yolk reserves
Factors that cause changes in diapause:
○
Temperature extremes
!
Hypoxia
!
Salinity stress
!
Dessication
!
Specific adaptation of Diapause II Embryos, have resistance
to:
○
Several species belonging to the Order Cyprinodontiformes
(killifish) experience complete habitat loss during part of the year
•
Lower -heart rate, BP, O2 capacity
!
Higher -CO2, osmolality
!
Convert NH3 to urea (urea is stored in tissues)
!
Converts air bladder to young; lowers overall metabolic rate
○
Absorb large amount of water prior to and
during early aestivation
1.
Mainly stored in muscle2.
Helps maintain ionic balance and 'buffers' urea
accumulation
3.
Lungfish lose a considerable proportion of body mass
when they re-emerge
!
Water flux:
○
Aestivation in Lung Fish:
•
Habitat Loss:
Increase in heart size
○
Increase in number of capillary beds
○
Decrease in air bladders
○
Anatomy:
•
Increase in mitochondria
○
Loss of Hb types
○
Increase in fatty acid metabolism
○
Decrease in muscle proteins
○
Metabolism:
•
Thermal hysteresis prevents ice crystal growth
○
As freezing point decreases, the production of AF proteins
increase in the blood serum
○
Contain antifreeze proteins
•
Crocodile ice fishes -lost capability of binding oxygen to the
blood (so blood is thinner to aid in blood circulation)
○
Loss of all functional haemoglobin genes in icefishes and
myoglobin genes in some species
•
Increase levels of mitochondria in cells and increased catalytic
efficiencies of enzymes increases energy production in polar fishes
•
*see slide with figure
•
Adaptations to Extreme Cold:
Aquatic & Terrestrial Adaptations
of Fishes
Monday,*September* 18,*2017
12:29*PM
Environmental challenges -temperature, oxygen, salinity, pressure
•
Habitat loss -Aestivation and diapause
•
Extreme cold -living in a frozen world
•
Adaptations of Aquatic Environments:
Increased metabolic rate
○
Increase heart rate
○
Similar cardiac output
○
Decrease heart size
○
Resting adaptations for chronically warmed:
•
*see slide with figures
•
Energy Conservation: chronically warm-adapted perch have
an intrinsically lower heart rate (at same temperatures as the
reference perch)
1.
Upper Limits: maximum temperatures tolerated is similar
between groups (=genetic plateau)
2.
Findings:
•
Study: European perch acclimatized for 3 generations to higher water
temperatures
Large gills
!
Low Hb-O2 P50
!
Low routine O2 consumption
!
Fish that are adapted to hypoxia conditions will have a Pcrit
shifted to the left:
○
Measure of tolerance to hypoxia = Pcrit
•
Tidepool species have a lower Pcrit compared to shallow
water species
○
Gill surface area is greater in more hypoxia tolerant species
○
Oxygen turnover rates are increased in more hypoxia tolerant
species
○
Routine metabolic rates are reduced in more hypoxia tolerant
sculpins
•
Some species will come up to the surface and role around to pick
up oxygen (and may even have emergence behaviour)
•
Study: Hypoxia Challenges in Fish
Actively takes up ions through gills
○
Absorbs water through skin
○
Excretes dilute urine
○
Freshwater environment -fish body is hyper-osmotic
•
Excretes ions through gills
○
Loses water through skin
○
Excretes concentrated urine
○
Saltwater environment -fish body is hypo-osmotic
•
Kidney: decrease in number of glomeruli
○
Intestines: increase permeability to water
○
Silvering and increase in body length (vs body mass)
○
Increase number of teeth
○
Increase chloride cells in gills
○
Increase gap junctions
○
Increase & decrease in gene expression levels
○
Decrease mucus
!
Increase columnar epithelium (impermeable to water)
!
Change in oesophagus:
○
Parr --> Smolt (transformations to changing environment to
conserve water)
•
Challenges of Osmoregulation in Freshwater and Saltwater:
Extreme pressure
○
Lack of oxygen
○
Extreme cold
○
Low food abundance
○
Low density of conspecifics
○
Electroreception?
○
Bioluminescence?
○
Challenges:
•
Lower metabolic rates
○
Solution:
•
Increased use of polyunsaturated lipids in lipid membranes
○
Causes an increase in osmolality (not as hypo-osmotic;
less energy to maintain ionic balance)
!
Increasing levels of TMAO (trimethyl amine oxide) in
tissues -acts as protein chaperone
○
Protein ratios changes
○
Decreasing production of urea
○
Maintaining body shape and protein functions:
•
Found below 6000-800m depths
○
Reduced levels of proteins and other components
found in white muscle
!
Acts as a shock absorber
!
Have specialized jelly tissue (high water content)
○
Ex. Hadal Snailfish
•
Under Pressure: Living in the Deep
They have adapted by using diapause stages during
embryonic development to delay the emergence (after
hatching) of young into a new aquatic environment
○
Diapause I-III
□
Diapause Embryo -production results in arrest in
diapause
!
Escape Embryo -production results in direct
development sand possible hatching
!
Four stages of development:
○
Main characteristic of all diapause stages is a reduction of
embryonic metabolic rates
○
Period Length Triggers
Diapause I days Intrinsic (genetic)
Diapause
II
Months-
years
Increased daylight
•
Fluctuating
temperature
•
Fluctuating O2
•
Rehydration of
perivitelline space
•
Rapid changes in abiotic
factors:
Diapause
III
Up to 4
months
Depletion of yolk reserves
Factors that cause changes in diapause:
○
Temperature extremes
!
Hypoxia
!
Salinity stress
!
Dessication
!
Specific adaptation of Diapause II Embryos, have resistance
to:
○
Several species belonging to the Order Cyprinodontiformes
(killifish) experience complete habitat loss during part of the year
•
Lower -heart rate, BP, O2 capacity
!
Higher -CO2, osmolality
!
Convert NH3 to urea (urea is stored in tissues)
!
Converts air bladder to young; lowers overall metabolic rate
○
Absorb large amount of water prior to and
during early aestivation
1.
Mainly stored in muscle2.
Helps maintain ionic balance and 'buffers' urea
accumulation
3.
Lungfish lose a considerable proportion of body mass
when they re-emerge
!
Water flux:
○
Aestivation in Lung Fish:
•
Habitat Loss:
Increase in heart size
○
Increase in number of capillary beds
○
Decrease in air bladders
○
Anatomy:
•
Increase in mitochondria
○
Loss of Hb types
○
Increase in fatty acid metabolism
○
Decrease in muscle proteins
○
Metabolism:
•
Thermal hysteresis prevents ice crystal growth
○
As freezing point decreases, the production of AF proteins
increase in the blood serum
○
Contain antifreeze proteins
•
Crocodile ice fishes -lost capability of binding oxygen to the
blood (so blood is thinner to aid in blood circulation)
○
Loss of all functional haemoglobin genes in icefishes and
myoglobin genes in some species
•
Increase levels of mitochondria in cells and increased catalytic
efficiencies of enzymes increases energy production in polar fishes
•
*see slide with figure
•
Adaptations to Extreme Cold:
Aquatic & Terrestrial Adaptations
of Fishes
Monday,*September* 18,*2017 12:29*PM
Document Summary
Extreme cold - living in a frozen world. Study: european perch acclimatized for 3 generations to higher water temperatures. Energy conservation: chronically warm-adapted perch have an intrinsically lower heart rate (at same temperatures as the reference perch) Upper limits: maximum temperatures tolerated is similar between groups (=genetic plateau) Fish that are adapted to hypoxia conditions will have a pcrit shifted to the left: Routine metabolic rates are reduced in more hypoxia tolerant sculpins. Tidepool species have a lower pcrit compared to shallow water species. Gill surface area is greater in more hypoxia tolerant species. Oxygen turnover rates are increased in more hypoxia tolerant species. Some species will come up to the surface and role around to pick. Some species will come up to the surface and role around to pick up oxygen (and may even have emergence behaviour) Parr --> smolt (transformations to changing environment to conserve water) Silvering and increase in body length (vs body mass)
