APS11007 Principles of Ecology and Conservation Flashcards
1
Q
What 6 key processes drive distribution and abundance?
A
- Colonisation and extinction
- Emigration and immigration
- Births and deaths
2
Q
Unitary organisms
A
- Easy to recognise genetically separate individuals
- Form is determinate, programmed by birth
- Variation smaller than in modular organisms
- Strong programming means local damage has serious consequences
3
Q
Modular organisms
A
- Genetic individual, genet, starts life as a single celled zygote but doesn’t follow set developmental programme
- Growth occurs by repeated production of modules (leaves, polyps etc)
- Indeterminate growth and development, not predictable
- Individual not dead until all modules are dead, local damage is unimportant
4
Q
The Life History
A
“Life history theory predicts how natural selection should shape the way organisms parcel their resources into making babies” Reznick, D. N. (2010)
5
Q
Life history questions
A
- When start producing?
- How often?
- How many offspring?
- Many small or few large offspring?
6
Q
‘Parity’
A
Number of times a female has reproduced
7
Q
Key traits of life history
A
- Rates, e.g. somatic growth and senescence
- Timing, e.g. maturation and frequency of reproduction
- Allocation, e.g. offspring size and number
8
Q
Somatic growth
A
Growth of body exclusive of gametes
9
Q
Senescence
A
- Process of deterioration with age
- Loss of a cell’s power of division and growth
10
Q
Semelparity
A
- Large number of offspring produced in a single reproductive event
- After which the individual soon dies
- E.g. many annual plants, some perennial plants, a few vertebrates
11
Q
Iteroparity
A
- Reproduction is spread out
- Produce offspring during repeated reproductive episodes
- E.g. most mammals, most perennial plants, many insects
12
Q
Annual life history
A
- Simplest
- An adaptation to living in seasonal environments
- One ‘generation’ per year, growth, seed and death
- Spend part of life as dormant seeds, can be viable for 10-100s of years
13
Q
Ephemerals
A
- Adult lifespan lasts only few weeks or months
- Desert annual plants (dormant seeds)
- Some amphibia (dormant eggs)
- Remain dormant most of life
- Emerge and reproduce in occasional years that conditions are good
- Complete life cycle in <8 weeks
14
Q
Population
A
- Group of organisms of one species that interbreed and live in same place at same time
- Compete for food, breeding sites and partners
15
Q
Metapopulation
A
- Larger scale
- Collections of populations linked via dispersal
16
Q
Survivorship
A
- How many individuals are expected to survive to any specific age (x), donated by lx
- Plotting the log of this number on y-axis and age on x gives survivorship curve
17
Q
Types of survivorship curves
A
- Type I, relatively high mortality later in life
- Type II, constant mortality throughout life
- Type III, relatively high mortality earlier in life
18
Q
Life tables
A
- Summarise births and deaths for organisms at different ages of lives. Shows quantities like survivorship for different ages
- Cohort life table, represents age-specific rates over the lifetime of a cohort of organisms born during a short time period
- Period life table, age-specific rates during specific time period of certain pop (different age groups born at different times)
19
Q
Column in a cohort table
A
- Survivorship, survival from age 0 to age x
- Survival (Sx), age-specific survival from age x to age x + 1
- Fertility (mx), mean number of offspring produced by each surviving individual over the age of x-1 to x
- Lx x Mx
- X x Lx x Mx
20
Q
What can be calculated from life tables?
A
- Measures of population growth
- Net reproductive rate
- Annual growth rate
- Generation time
21
Q
Net reproductive rate: R0
A
- Average number of female offspring produced by one individual over her lifetime
- R0<1, population declines, R0 >1, population grows, R0 = 1, stable
- Measure of per-generation population growth
- Measure of fitness
- Sum of lx x mx
22
Q
Generation time: T
A
- Average time between successive generations (birth of individual and birth of offspring)
- A weighted average of age (x) at reproduction of cohort
- Weights (lx mx) are the expected contributions from birth to the next generation arising at each future age
- Sum of x lx mx, all over R0
23
Q
Population growth rate: (lambda)
A
- R0 tells if population is growing, but not how fast per unit of time
- Population growth gives amount by which a population will grow each year
- R0 to the power of 1/T
