Topic 6 Flashcards
Designing the perfect plant
grow fast
* get large
* be toxic
* be thorny
* reproduce early
* reproduce often
* make lots of seeds
* make big seeds
* disperse seeds a long way
* live a long time
Can this be done?
No. Not all these things are possible, think of it think a budget. How to spend resources well as they are limited. B/c not enough resources to support all those traits. There are design and investment trade offs
Designing the perfect plant
A design tradeoff
(the same form cannot be
optimized for 2 different tasks)
- make big seeds
- disperse seeds a long way
Big seeds can’t travel far
Small seeds can travel far
Dandelions seeds evolved to disperse small seeds far
Avocado seed evolved to be high in resources for offspring but can’t travel far
Designing the perfect plant
An investment tradeoff
(the same resources cannot be
invested in two different activities)
- make lots of seeds
- make big seeds
Ex: plants only have so much H2O, minerals from soil, etc
—> so could produce a lot of offspring in hopes some live (low chance of survival)
—> or could produce small amounts of offspring to invest in increasing chance of survival
Designing the perfect plant
Name three variables you could
measure if you were studying
animals instead of plants.
Growth
Size
Defence —> can be other things to consider
Reproduction
Offspring characteristics
—> ex: the quality, size, amount
Lifespan
Life History
The schedule & characteristics of an organisms growth, development, reproduction & survival.
Ex:
How fast was growth, did they reproduce, how many offspring, when in life did they have offspring, when did they die.
Life History Traits
- Lifespan
- Age at 1st reproduction
- Mortality rates
- # offspring/fecundity
- # reproductive events
- Parental care
- Offspring size
Study of 10 darter species from 64 locations
Female size vs. fecundity:
- the females of larger darter species produce more eggs
Egg Size vs. # Eggs:
- darter species that produce larger eggs lay fewer
Number of offspring an individual produces trade off with size of offspring.
—> some enviro it’s more beneficial to make larger or smaller eggs
Trade offs in multiple species and in diff environments
—> understand why life history traits/trade off evolve
—> under what conditions are traits advantageous
Life history trade off
- might predict that natural selection result in all darter species being large so they can produce more eggs - there’s a negative correlation between egg # and size.
—> producing more egged means those eggs will be smaller
Reproductive trade-offs in plants
plants that produce larger seeds produce fewer.
(# of seeds vs seed mass(size))
This is a common trade off in many species
Alternative Life Histories: Coho
salmon
Trade offs within species
- diff phenotypes
Maturity
- when become able to repro
— varies for this species
— reason for diff is b/c have diff repro strategies
— both can have success for competing for mates
- external fertilization
Hooknose
- mature at 18 months
- large size when mature
- more colour
- fight for access to females
Jacks
- mature at 6 months
- small size when mature
- reason to small size and less colour is to look more like females.
- “sneaker male”
The “principle of allocation”
How they decide to spend/allocate their resources.
— quantify the differences in individuals
1st circlelonger lived individual:
growth 30%
maintenance 25%
defense 10%
reproduction 15%
activity 20%
2nd circleshorter lives individual:
growth 5%
maintenance 17%
defense 3%
reproduction 55%
activity 20%
Niche concept
Range of resources that a species uses
Or
Range of conditions under which a species could exist
Fundamental niche
Conditions under which a species can survive
— not considering interspecific interactions
- will be broader than the realized niche
Realized Niche
The portion of fundament niche that’s actually used
— interspecific interactions are considered
