Lecture 5.3 Flashcards
What was the predator prey example discussed in lecture
Prickly pear cactus in Australia
Imported from South America by a guy. Exploded around the country covering millions of acres. After some decades they went back to S. America and found a moth that is a parasite to the cactus. Introduced the moth in Australia
Predator prey relationships are relatively stable due to
Adaptations by both
There is always a ___ for prey and there is always ___ for predators
refuge
an alternative food species
a progression of changes through time in a community from pioneer species to climax species
Succession
No soil at the beginning, it has to be made
After a landslide
When a glacier retreats it leaves scowered rock
Takes longer, potentially centuries
Primary succession
when there is soil present at the beginning
Secondary succession
At the beginning of a sequence are ____species at the end are ___ species
pioneer
climax
More kinds of species emerge at the ___ of a sequence
End
As the community becomes more complex amount of ___ goes up
interactions
community + its physical environment
ecosystem
A type of community on the world level, communities of a same type the world over
Biome
Much of what is done with populations is
numeric
number of organisms born per female per unit time
Birth rate
Name the 5 things that can affect population size
Immigration Emmigration Birth rate Death rate Extinction
the number of organisms to die per unit time
Death rate
the population size is small then it might go extinct in what two ways
direct extinction
inbreeding
species tend to exist in clumps
Clumped population arrangement
Could be that the more spread out they are the more resources they have
If you are away from other groups, then predators won’t notice you
Less competition
Less predation
Regular/uniform/scattered population formation
the less common population arrangement
random distribution
looking at a population over time, numbers increase, hypothetical situation, does not exist in nature
Exponential population growth
Grows slowly, then increases, then levels off and comes to a halt
Sigmoid/logistic population growth
carrying capacity of an environement =
K
On a sigmoid curve where the curve is steepest represents
where the population is growing the best
The best time to harvest =
K/2
The science of statistics of populations
Started originally as a human science for life insurances
Demography
where one puts the data from a demographic study
life table
Start with a cohort of individuals and watch them through their life and how they survive
Demography
- Data most often used and graphed is the Proportion of organisms surviving at beginning of age interval
Survivorship curve
Some organisms live to an old age and then die
Type I survivorship curve
Can die anywhere from beginning to end Ex: birds
Type II survivorship curve
insects Die immediately
Type III survivorship curve
- Can collect from cohort
- Take females and look at them through their life and see when they have kids
- Can add up the offspring and see what’s going on in a population
Birth data
Having an offspring early means
the offspring can also have offspring
how long it takes a population to double
Doubling time
Birth data can help us to calculate
doubling time of a population
