L1 Revision Flashcards
(19 cards)
What is demography?
Study of processes such as births and deaths to predict and understand the changing structure of populations
Give some examples of population composition
How many of each age class
How many males vs females
How many juveniles vs adults
Size of individuals
What does life history theory predict?
How natural selection should shape the way organisms parcel their resources into making babies
What is iteroparity and semelparity?
Iteroparity - grow, become sexually mature, reproduce every year and have a post-reproductive phase
Semeparity - grow, become reproductive and die after reproducing
What are pulsed and continuous breeders?
Pulsed - reproduction is confined to a set time/season
Continuous - can reproduce at any point in the year
What classes come under pulsed and iteroparous breeders?
Most birds and mammals
What comes under pulsed and semelparous breeders?
Some fish and plants
What type of breeders are humans?
Continuous and iteroparous
What is the life history of an organism shaped by?
Natural selection to produce the largest possible number of surviving offspring into future generations
What does natural selection favour?
Combinations of traits that maximise fitness
What is the principle of allocation?
Each organism has a limited amount of energy that it can allocate for maintenance, survival, growth and reproduction
Energy allocated to one function is not available for another
Give some types of trade-offs
Intra-individual trade-offs:
-Reproduction vs Survival
-Reproduction vs Growth
-Reproduction vs Condition
-Current reproduction vs Future reproduction
-Number of offspring vs Size of offspring
-Number of offspring vs Survival of offspring
Inter-generational trade-offs
-Parental survival vs Number of offspring
-Parental survival vs Offspring condition
What is survivorship?
How many individuals in a population are expected to survive to any specific age (known as lx)
What are the types of survivorship curves?
Type 1
Type 2 - constant mortality
Type 3 - higher mortality earlier in life
What can be calculated from life tables?
Population growth rate:
-Net reproductive rate (per generation population growth rate)
-Annual growth rate (how the population changes over a year)
Generation time
What is the net reproductive rate?
The average number of female offspring produced by one individual female over her lifetime (from birth to death)
Ro < 1 = population is declining
Ro > 1 = population is growing
Ro =1 = population is stable
What can you interpret from the net reproductive rate?
A measure of per-generation population growth rate
A measure of fitness (lifetime reproductive success)
What is generation time?
The average time between successive generations (average time between birth of individuals and births of their offspring)
Why do we need to use generation time?
Net reproductive rate does not tell us how fast a population is changing whereas generation time can
