BIol 371 Robinson lectures Animals Flashcards
What are the terrestrial lineages, what does terrestrial lineage mean?
Arthropods, such as insects, myria pods (centi and millipedes) and arachnids (spiders)
Vertebrates- reptiles
Amniote vertebrates- birds and mammals
Amphibians
What terrestrial lineage is still aquatic in its lifecycle?
Amphibians
What are the advantages to living in water?
Water supports the body
Reproduction is facilitated by flow, gametes don’t dry out-
Less fluctuation of temperature in water than in air
Metabolic wastes are removed easily
Sound transmits well
It limits metabolic rates
Explain why its a benefit that water supports the body
- water holds up body which is why we don’t see gelatinous zooplankton or jellyfish on land as there’s no medium there that will hold up their bodies.
Explain why its a benefit that reproduction is facilitated by flow
gametes don’t dry out- gametes can travel through water in order to reach their destination, water is a moist environment for them.
What are the advantages to living in water?
Water supports the body
Reproduction is facilitated by flow, gametes don’t dry out- gametes can travel through water in order to reach their destination, water is a moist environment for them.
Less fluctuation of temperature in water than in air
What are the advantages of water in removing metabolic wastes?
When aquatic organism makes waste, water dilutes it and carries it away. Land doesn’t have this easy way to dispose of waste.
What are the advantages of sound for aquatic organisms?
Sound is transmitted well in water, different in air
What are some disadvantages to living in water?
Density and viscosity of water causes cost of locomotion, visual range
Limits metabolic rates
Lower oxygen content
High thermal conductance
How is the density and viscosity of water a disadvantage?
As water is more dense and 50x more viscous than air, Takes a lot more energy to displace water than in air. Locomotion is much slower and energy consuming. Also is hard to see in.
How is the lower oxygen content in water a disadvantage?
Theres a low oxygen content in water, animals in water have to breathe more water than animals in air have to breathe air to get the same amnt of oxygen.
How is high thermal conductance a disadvantage?
Water heats up more quickly, means organisms will heat up more in water than air in warm temps.
What are challenges to living on land?
Desiccation- less liquid so there’s more chance of drying out
Temperature extremes- They are extreme on land more chance of freezing or boiling
Excretion- harder to remove waste from you
Reproduction- gametes can’t flow in water, easily dry out, need to find ways to travel without drying out in order to do external fertilization.
Locomotion- harder to move as water isn’t carrying you
Gas exchange- finish later
What are the four major challenges to living on land?
Dessication (not drying out)
Gravity- In an aquatic environment water is entirely supporting body, need structure to stop gravity from crushing you.
Breathing air- Breathing air is different than breathing water, more access to oxygen in air but need to convert it to work in a water based body.
Sensory systems and structures- There’s different sensory systems and structure made for air and water- challenge is taking information from out side body in air and translating that to water in the inside of the body.
How we do we avoid desiccation on land?
With mechanisms to reduce water loss and mechanisms to replace water loss
What are some mechanisms to reduce water loss?
Thick skin, waxy cuticle- is external structure which allows you to retain moisture
Behaviour- loss- for example some animals will avoid dry areas/dry habitats.
Produce concentrated urine (loop of Henle)- In the vertebrate kidney theres a loop of henle that reabsorbs water, want a longer henle if your in a dry environment in order to reabsorb more water and produce more concentrated urine.
What are some mechanisms to replace water loss?
We can drink and eat moist food
We have metabolic water that nourishes us, this water is produced by breaking of atp.
In kangaroo rats all of their water is produced by atp.
What is aestivation?
Is when organisms form a cocoon around themselves of mucus in order to tolerate desiccation during dry periods. Coccoon contains living tissues to prevent animal from getting sepsis and protect it from bacteria
What is an example of an animal that does aestivation?
African lung fish
Describe how rotifers adjust their reproduction in stressed vs unstressed enviroments
In unstressed environments (wet)- rotifers do asexual reproduction where a asexual female form a asexual egg which then also turns into a asexual female. The loop goes on and on.
In stressed environments (dry)- rotifers switch to sexual reproduction and do this by having the asexual female produce a asexual egg which forms into a sexual female that produces males through their unfertilized egg.
This male producing sexual female produces a meiotic egg which become a degenerate male, this male then copulates with the sexual female which results in a fertilized egg developing within the female, this zygote is resistant and can survive if the local water supply should dry up. The zygote stays dormant until conditions are favourable- this is when it is released to hatch in water and becomes an asexual female again.
In an environment are rotifers asexual or sexual?
Usually a mix of both, never one or the other
How can temperature extremes damage an animal?
Heat can denature proteins, extreme cold can make ice crystals in the cell and damage it’s functions
How do organisms deal with temp extremes?
Can avoid temp extremes by producing your own heat (thermoregulation)
Can avoid through behaviour- see animals that forage only during suitable temperatures.
Some animals do freeze avoidance, they lower the point that they can freeze at by concentrating their sugars.
Another way to avoid temp extremes, organisms use antifreeze proteins that bind with ice crystals make them small, and then cause less damage towards the cell. Do this by increasing phospholipids.
also do this through life cycle stages- through Hibernation, lowering metabolism through this in order to conserve energy in cold.
How do gametes avoid dessication?
they do internal fertilization- gametes enter body which is aqueous or stay in body in case of eggs.
How do embryos avoid dessication
Aquatic larvae- have embryo first develop in larvae so it can avoid dessication by living in water until adulthood.
Thick covering on eggs- turtles do this, do thick shells to protect embryo
Amniote (reptiles, birds, mammals) vertebrates surround embryo in
amniotic membrane- amniotic membranes can also create a fluid environment for a developing embryo
How do animals excrete waste in a way that they conserve water?
In terrestrial environments you want to discrete water w out losing a lot of water.
Production of nitrogenous waste is in the form of ammonia, this is toxic so having it be near the body and be concentrated is bad for animals.
To avoid this animals form substances out the water and create urea, which is less toxic and then can be exposed of at high concentration to avoid water loss.
Uric acid is less toxic than urea, is not soluble so it will ppt out of solution- lose little water in process. Is useful when retained in eggs, the formation of uric acid allows waste crystals to be isolated from the developing animals.
Why is a moist surface needed for gas exchange?
When breathing in o2 we need it to dissolve into and diffuse across membranes, dissolving the o2 in liquid allows this to happen.
Why is the gas exchange system internalized?
Is internalized to reduce water loss in mammals, allows them to conserve moisture as water isn’t released when gas exchange occurs.
How does the insect tracheal system reduce water loss?
Spiracles which are the small opening on the tip of the trachea (where gas exchange occurs) reduce water loss by opening and closing, so they only open when they need air and close when they need to conserve moisture
How do nasal passages in mammals reduce water loss?
The nasal passages are cool and extract water in the air exhaled through condensation.
Why is gas exchange better in air?
Air contains more oxygen, and oxygen can diffuse through air 10000x faster. Therefore easier to obtain o2 and do gas exchange.
Is sound faster in air or water?
400% Faster in water, higher pitched, has higher frequency, is louder
Is the speed of light better in air or water?
Iight is 25% slower in water so air.
How does olfaction work in mosquitoes?
The mosquitoes have hair-like structures on their antennae which they use to sniff out their hosts. The pores on these hair allow odor molecules to enter and transport through fluid and then bind to receptors sending the info to them.
What is an example of a organ that senses sound in insects?
The typanal organ, is a stretched membrane with air on both sides of it which detects vibrations using it.
What is an example of an organ that senses sound in humans?
The middle ear, is an air filled cavity, and the oval window is where vibrations in air are converted into vibrations in fluid, between the eardrum (air filled) and the oval window connecting to fluid filled- sounds are amplide by 20.
Where did our inner ear bones come from?
the reptilian jaw
How many ear bones do reptiles have?
one
