Theme 3 - Dr. Robinson Flashcards
What are the two main terrestrial lineages?
Athropods (insects and arachnids) and Vertebrates (amniote such as reptiles, birds, and mammals)
Which lineage on land still needs water to complete their lifecycle?
Amphibians
How are Temperature, Waste, Sound, Body Support, and Reproduction affected by living in water?
Temperature is stable
Metabolic waste is removed
Sound transmits well
Water supports the body
Reproduction is facilitated by flow and the gametes do not dry out.
What is the benefit of life in water which has a high heat capacity?
Stable thermal environment
What is the benefit that oxygen has in air vs water?
In water, oxygen has to be dissolved, so there is less. In air, oxygen diffuses quickly and flows easily across a surface.
What is the corresponding challenge adaptation to land for each quality in water?
1) Stable temperature
2) Diffuse Waste
3) Gases diffuse from water
4) Weight supported by water
5) Gametes exchanged in environment
1) Desiccation
2) Concentrate waste and reduce water loss
3) Gas exchange mechanism
4) Requires weight supporting strategy
5) Protective coating or internal structures.
What are 5 challenges of living on land?
1) Desiccation
2) Rid of toxic wastes
3) Breathing air
4) Sensory systems and structures
5) Gravity
What are 3 mechanisms to reduce water loss and avoid desiccation?
Develop a skin or waxy cuticle
Behaviour changes
Produce concentrated urine
What structure was developed to concentrate urine?
Loop of henle
What are the mechanisms used to replace water loss?
Drink, eat moist foods, and metabolic water
What is the term for desiccation tolerance?
Aestivation
What is a change to the lifecycle as a mechanism to deal with water loss?
Parthenogenesis (in rotifers, where habitats fluctuate between suitable and unsuitable periods)
This is asexual reproduction
What is a performance curve and how do cells become affected at the temperature goes towards 0 and 45 degrees?
Describes rate and efficiency of animal’s processes
Cells function between 0 to 45 degrees
Below 0 degrees, ice crystals destroy organelles and cell membranes and approaching 45 degrees proteins and nucleic acids denatures
How do organisms avoid damage by extreme temperatures?
Endothermy
Sweating
Behavior
What is freeze tolerance?
Ice nucleating proteins
higher proportion of phospholipids
Lower metabolism
What are the challenges with excretion of wastes on land and how do organisms evolve to adapt to them?
Ammonia is toxic. Urea is less toxic, and can be stored in higher concentrations which limits water loss
Uric Acid is insoluble and is retained in the egg and in waste.
How do organisms protect their reproductive structures from desiccation?
Gametes - internal fertilization and mate finding
Embryo - Aquatic larvae, shells on eggs, amniotic vertebrates (membrane and fluid)
Why do mitochondria need Oxygen?
To produce ATP
How can gas enter a cell?
Must be dissolved in solution
How much faster in the diffusion rate of oxygen in air than in water?
10 000x faster
What must a respiratory surface have in order to exchange gases?
A film of fluid on it to capture gases
What is the benefit of internalized gas exchange?
Inward, protected, moist surfaces
Increased surface area
reduces water loss
(Tracheal system in insects and nasal passages in mammals)
What sensory signals are there in air and how are they transmitted?
Light: radiant energy
Sound: Waves of pressure
Smell/Taste: Small molecules
Touch: Mechanical force
In water, speed of sound is (faster/slower) and speed of light is (Faster/slower)
400% faster
25% slower
