Theme 3 Part 1

Question 1

What is special about life on water that isn’t the same for life in air

Answer 1

High heat capacity in water
Waters a universal solvent
Waters viscous
Waters more dense than air

Question 2

What are the challenges in on land

Answer 2

Dessication
Concentrated waste
Need a gas exchange mechanism (in water gasses diffused by water)
Need a weight supporting strat (no more buoyancy)
Gametes need a protective coating or need to be held internally

Question 3

How do organisms on land prevent cells from drying out (dessication)

Answer 3

Need to keep a certain concentration of fluids (be bathed in fluids)

The humidity inside the animal (100%) needs to be greater than the environments humidity

Maintain a balance between water loss and gain

Question 4

What characteristics do organisms have to reduce water loss

Answer 4

Have waxy cuticle skin (protective barrier)

Change behaviour (shift their schedule to avoid times of great water loss)

Produced concentration urine (removing water from urine to preserve water) by loop of henle

Question 5

What characteristics do organisms have to replace water loss (once it’s happened)

Answer 5

Drink or eat moist food

Use metabolic water (water made by their own metabolism this where most of their water comes from)

Question 6

What is an example of dessication tolerance

Answer 6

Instead of avoid it the push through it

Aestivation which is a state of dormancy

Lung fish use this by digging in mud during dry season. They form mucus around themselves and then when water comes back they dig out of mud

The mucus protects from skin infections blood loss and bacteria sepsis

Question 7

What is an example of organisms changing their life cycles to avoid dessication

Answer 7

Parthenogenesis in rotifers

Initially doing asexual reproduction when pond is stable and wet

When instable environment they reproduce sexually

Question 8

What is the asexual. (Unstressed) life cycle of rotifers

Answer 8

Makes diploid asexual egg then egg turn into asexual female

Question 9

What is the sexual (stressed) life cycle of rotifers

Answer 9

Asexual females asexual egg turns to sexual female

The female is inseminated by a meiotic egg which creations a diapausing egg

The diapausing egg goes into the sediment and pops up when environmental is favourable

Question 10

What is a performance curve

Answer 10

Describes the rate and efficiency of the animals processes over a range of temps

Question 11

During temperature extremes, What happens to the cells below zero degrees

What happens to the cells as they approach 45 degrees

Answer 11

Ice crystals form and destroy organelles and cell membranes

Proteins and nucleic acids unfold and lose function

Cells function between 0-45 degrees

Question 12

How do organisms avoid temp extremes

Cold and hot

Answer 12

Endothermy (produce their own heat)
Sweat to cool down
Differ behaviours to avoid extremes
Freeze avoidance to lower freeze point

Question 13

How do organisms do freeze tolerance

Answer 13

Ice nucleating proteins (help smaller crystals form so they down get hurt by them)

Higher proportion of phospholipids

Lower their metabolism (hibernation, torpor)

Question 14

How do organisms on land limit water loss through excretion

Answer 14

On land ammonia doesn’t get diluted by water so it’s toxic and doesn’t help

Urea (which is less toxic and can be stored in higher concentrations) is used now

As well as uric acid which is insoluble and can be stored as a crystal poop that doesn’t contact the organism

Question 15

How are reproductive structures protected from dessication

Answer 15

Internal fertilization
Mate finding (need to find mate for internal fert)

Embryo is present with membrane (fluid) surrounding the embryo for protection

Question 16

What has to happen to has before oxygen can enter the cell

What’s easier to get rid of

Answer 16

It has to be dissolved in a solution then go into the cell

It’s easier to get rid of co2 but harder to get oxygen in the water than on land

Question 17

What changed for gas exhacnge in air breathing animals

Answer 17

Diffusion rate of oxygen is 10000x faster in air and there’s a high oxygen content in air

Since air has lower density and viscosity, the energy needed to move water across a respiratory surface is decreased

So the respiratory surface is covered by a thin layer of fluid and is inward to prevent evaportion

So every cell in insect touches the tracheal system (tracheoles) that lead to the outside. So cell always connected to air

Question 18

What are sensory receptors, what signals to they detect

Answer 18

Things that detect signals (stimuli) from out side

Light (radiant energy)
Sound (waves of pressure)
Smell, taste
Touch (mechanical force, displacement)

Question 19

What does the speed of sound depend on

Answer 19

Compressibility
If more compressible, sound travels slower

If less compressible(diamond), sound travels faster

Faster in water than air

Question 20

What does the speed of light depend on

Answer 20

Faster in air than water

If more compressible travels faster
If less compressible travels slower

Question 21

What does speed of smell depend on

Answer 21

Pressure
Diffusion rate of a molecule
Temperature
Turbulence

Question 22

What is amplitude and wavelength on a graph

Answer 22

Amplitude (how loud) is the up and down distance

Wavelength it peak to peak distance

Question 23

How do insects smell

Answer 23

Through olfaction (they have hair like structures on antannas)

Pores of the antennae let’s odour molecules from air to enter then the odor molecules dissolve into a fluid.

Then they can be detected by the Chemosensor receptors

Question 24

How to insects hear

Answer 24

Mechanosensors

Insects have a tympanal organ that has air sack behind it. The membrane in front of the air sack can vibrate.

The vibrations are detected by sensors connected to the air sack

To detect diff frequencies, diff thickness of the membrane vibrates at diff frequencies . That tells the frequncy

Ear next to legs

Question 25

How does hearing work in vertebrates

Answer 25

The ear is an air filled cavity. The ear drum also has air on either side of it so it vibrates in response to sound

Air on one side of eardrum, fluid on the other. Bones in the ear transfer the vibrations from the eardrum to the fluid media inside the spiral to amplify the sound

Question 26

What did the inner ear bones that amplify sounds evolve from

How many inner ear bones do reptiles have

Answer 26

From parts of the jaw

Reptiles have one inner ear bone

Question 27

Where does sight move faster, how does it happens in land animals

Answer 27

Move faster in air

In water, the size of the eyeball doesn’t lead to diff in sight

On land, the larger eyes size increases the visual range (can see much further)

Question 28

What is the hypothesis of light sensing and eyes size

Answer 28

The transition from water the land is cause by the diff ranges of sight they could have on land

Eyes shift from the top of head to the side of the head