Lecture 1; Adaptations, movements and colonization

Question 1

Direct colonization

Answer 1

direct movement of species from organisms evolved in oceans moving into freshwaters

Question 2

Secondary colonization

Answer 2

Terrestrial/land ancestors evolved into freshwater organisms

Question 3

examples of direct colonized organisms

Answer 3

• crustaceas, molluscs and fish

Question 4

examples of secondary colonized organisms

Answer 4

• insect groups, mollusca

Question 5

some adaptations for respiration

Answer 5

• air breathing
• plastron
• pigments
• tracheal gills

Question 6

adaptations for coping with flow

Answer 6

• streamlines shape/body parts ‘hydrofoils’
• suckers
• modified gills
• modified feeding appendages
• hook and silk

Question 7

Adaptations related to coping with drought and food availability

Answer 7

• life cycle traits
• niche separation
• dormant stages; diapause

Question 8

leaves on Nuphar lutear ‘Brandy Bottle’

Answer 8

• large flat leaves on water surface

- under water; thinner leaves

Question 9

Adaptation of leaves on nuphar lutear

Answer 9

• under water leaves; fold up and reduce resistance when there is an increase In flow velocity

Question 10

colonization

Answer 10

a process where organism disperse, come into contact with a new habitats
choose an area suited to

Question 11

What time of day/year are organisms more likely to move upstream?

Answer 11

at night and summer

Question 12

Macroinvertebrate drift

Answer 12

movement downstream of invertebrates either involuntarily due to disturbance or volunatirly

Question 13

3 types of drift

Answer 13

• catastrophic
  behavioural
  Constant

Question 14

catastrophic drift

Answer 14

due to unfavourable conditions, may be washed into the flow,

Question 15

Behavioural drift

Answer 15

some form of diurnal periodicity involved

actively enter the drift by choice

Question 16

Constant drift

Answer 16

Occurring all the time at low levels

Question 17

why drift at night?

Answer 17

avoid predation by fish

Question 18

4 adaptive advantages of drift

Answer 18

• colonization of downstream areas and of disturbed patches
• when food is scarce
• avoid unfavourable condition-pollutants, temperature, ice, floods, drought, low DO
• avoid predation

Question 19

Definition of hyporheic

Answer 19

• Saturated interstices beneath the stream bed and into the stream banks that contains some portion of channel water or surface water infiltration

Question 20

Hyporheos

Answer 20

community which lives in the hyporheic zone

Question 21

temperature in hyporheic zone

Answer 21

less variation diurnally and seasonally

Question 22

light in hyporheic zone

Answer 22

light doesn’t penetrate > 4.5 X grain size of sediment

Question 23

Current velocity in hyporheic zone

Answer 23

reduced when water infiltrates

Question 24

DO in hyporheic zone

Answer 24

declines with decreasing depth ( at 30cm deep, can be 5% of that at surface)

Question 25

what is CO2 linked to in hyporheic zone

Answer 25

linked to respiration and flow

Question 26

Nitrate in hyporheic zone

Answer 26

hyporheic plays major role in transfer between terrestrial and aquatic environments and acts as a buffer zone

Question 27

4 advantages to living in the hyporheic zone

Answer 27

• lack of predators
• plentiful food
• more steady environment
• survival during adverse conditions

Question 28

5 disadvantages of living in hyporheic zone

Answer 28

• limited space
• reduced current velocities
• low DO, high CO2
• lack of light, very dark conditions
• accumulation of waste

Question 29

osmoregultion

Answer 29

the maintenance of constant osmotic pressure in fluids of an organisms by control of water /salt concentration

Question 30

Osmoconformers

Answer 30

maintain an internal environment which is isotonic to their external environment

Question 31

Difference between osmoregulators and osmoconformers?

Answer 31

• osmoconformer= ONLY MARINE organisms

- osmoregulators = freshwater OR marine organsisms

Question 32

Adaptations of caddisfly

Answer 32

• streamlined cases (flow)
• flattened legs; hydrofoil
• can orientate with flow