12. Adaptions And Colonisation Flashcards
What is direct colonisation
One done by an animal such as a fish, actively swimming
What is secondary colonisation?
Mainly land ancestors. Small snails insects and plants
What happens with animals and salt water?
Normally a defined line where you can’t have more salt in body than water, however some crabs can survive
How did animals first start to move inland?
Through rivers, adapted to fresh water
How many animal orders are there in fresh water in the USA?
13
What is strange about freshwater communities globally?
They are all very similar
What are some adaptations for respiration?
Air breathing, plastron, pigments and tracheal gills
What are some adaptions for coping with exploiting flow?
Streamlined shape, hydrofoils. Suckers. Modified gills, modified feeding appendages. Hooks. Silk
Adaptations related to drought and food availability?
Life cycle traits, dormant stages diapause
What adaptations do water crow foot have?
Streamlined leaves reduced flow resistance
What can rudenculus do?
Shed leaves and regrow in spring and summer
Which family shows the most adaptions?
Insects
What do Caddisfly do to protect themselves?
Make cases which they hide in
What blepharoceridae can do to to stay on rocks river flow?
They use suckers to cling to rocks
Which insect has a flattened body to stop being washed away in rivers
Rhithrogena, mayfly larvae
What is the boundary layer?
Area at the bottom of the river which sees little to no flow
What does a simulacra have to catch food?
Filtering fans
Which Caddisfly spins nets used for catching food?
Hyropsychidae
What things lead to the persistence of survival?
Dispersal, contact, choice
When do insects tend to do the most diurnal and nocturnal movements?
Different times for different species
Why do mayfly fly upstream
To lay eggs
Where do other species of mayfly lay eggs?
Beneath stones
What is invertebrate drift?
The movement downstream of invertebrates either involuntarily or on purpose
What is catastrophic drift?
Unfavourable conditions, did not drift on purpose
What is behavioural drift?
Some sort of diurnal periodic involved
What is constant drift?
Occurring all the time at low levels
Why do organisms drift at night?
Avoid predation by fish
How far do organisms travel in drift?
50-60m, low in winter
How can we catch species drifting?
Big nets in rivers
When do species drift the most?
About 11pm
Where did evolution start first?
In the oceans
What does pano conform mean?
To follow the level of salt in the water with there body
How many fresh water species groups are entirety aquatic?
5
What is a macrophytes?
Larger aquatic plants
What is a main adaptation for insects?
Most type and shape
How do Caddisfly make their case heavier?
Weighted stones or ballast
In Rhithgena how does it cling on to rocks?
Suckers like gills on its front
How do larger organisms get upstream?
Swim
What can constraint drift be defined as?
A low level from of the other two drift mechanisms
When is the peak of drift
Time of maximum darkness
What happens when there is artificial light on a stream?
No daily pattern to drift
Where is there a stronger pattern of drift?
In stream with predator fish
What are the 4 advantages to drifting?
Colonisation downstream, when food is scarce, avaoid unfavourable conditions, avoid predation
What are the 3 main dimensions of a rivers
Lateral. Longitudinal and verticals
What other dimension or scale can impact rivers
Temporal
What is the hyporheic zone?
The zone under and sounonding the river underground
Where is the hyporheic zone most important?
In gravel rivers
What is the name of the community that live in the hyporheic zone?
Hyporheos
How deep can this hyporheic zone be?
1 Meyer below the surface of the ground
Who developed theories on hyporeic zones in Montana?
Jack Stanford
What organisms are found below 40cm of the river bed?
Meiofauna
In terms of temperature, what is different than the normal river channel?
Temp is less variable
Why is it dark in the hyporhous?
Light cannot penetrate the river bed
Compared to the river above. How does the hyporheous compare oxygen wise?
5% of that at the surface
Is CO2 higher or lower in the hyporheous?
Higher
How much make acidic is the hyporheous?
1 pH more acidic
What are the advantages to living in the hyporheous ?
Lack of predators, plentiful food, more steady environment, no floods
