Biology 12000, Ecology I, Wall

Ecology -the scientific study of the distribution, abundance of life and the interactions between organisms and their natural environment.

-Physiology
- Behaviour
- Evolution
- Genetics
- Applied ecology: Conservation biology
- Applied ecology: Ecosystems management
- Applied ecology: Population management.

T.R.Malthus.

-Descriptive ecology
-Physiological ecology
-Evolutionary ecology

How organisms are adapted to their environment.

A quantitative experimental approach to testing hypotheses and detecting patterns.

They want to break down complex systems to understand them.

They look at a system as a whole to understand it, without breaking it down.

Observation, careful experiments, replication and statistical analysis important.

Because some organisms are abundant for a short time, some are not so abundant, but for a long period of time.

The range of environmental factors that individual can tolerate (eg temperature: 4-17 degrees).

There are lots of environmental factors that determine whether organism is able to live in that part of the environment, we have to put together to define a niche for an individual.

Temparature, water, wind, light, salinity, pH.

Effect of temperature on other aspect of the environment, eg food availability.

The niche in which an org. can live.

The one that has narrow niche breadth.

Depends on the stability of the environment.

It is not the average temperatures, but frequency of occurrence of extremes.

Because they depend on the stability of the environment they live in. Their niche is very narrow, so if the env. changes, they cannot tolerate those changes.

An org. with wide niche breadth, can tolerate wide range of conditions. But can be easily outcompeted by specialists.

For small.

For big ones.

Habitat is the environment where the organisms lives, niche tell us how is the habitat used.

Niche for an org. in the absence of other organisms, ideal conditions.

Niche for an org. in the presence of other org., predators, competitors, parasites, etc.

Within a species of vertebrate smaller individuals are more often found in warm climates near the equator, while larger are found in colder regions.

Larger animals produce more heat and lose less (small surface area relatively to their mass).

In mammals, individuals in warmer climates also tend to have longer limbs and appendages.

Adaptation for different temperature environments. In warmer environments lower surface area/mass ratio to lose less heat.

Reversible physiological changes that help maintain the functioning of the org. under changed enviromnent circumstances (eg biochemical changes in enzyme production after a change in the env.

Diff. growth forms that help org. survive in diff. environmental circumstances. Acclimation.

Supercooling, organisms produce glycerol which acts as an antifreeze for living through cold environmental conditions.

Acclimation,
Hibernation,
Dispersal,
Diapause,
Bergmann's rule,
Allen's rule.

Quadrat, number per sample, use traping net - catch per unit fishing effort, traps.

Footprints, scat/frass samples, burrows - damage to the env., vocalisation frequency, number of nests, etc.

Quantitative, must give a numerical measure.
Comparible - the technique should be able to work different times of the day/year/weather.
Cost effective.
Biologically relevant to the org. we study - using appropriate scale (no use measuring elephants with a quadrat).

Mark, release, recapture next time, calculate using:
N of marked animals in sample/total caught in sample (2nd day) = Size of marked population (1st day)/Total population size.
For ex. 50/200 = 120/ TPS

It assumes stable population.
Mark has to have no affect on animal.
Ignores immigration, emigration.

Appropriate sampling technique, timing of sampling (because of different activity of animals at diff. times of day/year/etc.), number of samples.

Regular
Random
Aggregated
Binominal (very clumped).

Almost all the time will get the same number of individuals per quadrat, because they are evenly distributed, so plot - one high line in the middle, two small on each side of it.

Normal-poisson distribution plot. Normal bell-shaped distribution, but slightly moved to the left.

Logarithmic distribution plot. Bell shaped distribution strongly moved to the left.

Binomial distribution. Most of the times get zero. Very small N of occasions will get large number per plot. Very important indication of number of samples we need to take.

We will know how many samples we need to take to measure abundance correctly (more aggregated the distribution, more samples need to be taken);
Our ability to compare populations, detect parasitism etc;
How we handle, analyze and interpret the data - parametric or non-parametric statistics?

Birth rate, Death rate, Immigration, Emigration.

The basic/intrinsic rate of reproduction. The maximum rate of increase in the population in unconstrained environment.

The max. number of eggs that a female can produce. Only females drive changes in abundance.

1. Age of reproduction of female. How long it takes to reproductive age;
2. frequency of reproduction
3. number of offspring produced
4. reproductive life span - for how long live and being able to reproduce.

Net rate of increase : Births - Deaths.

Using population age-structure.

Weight
Size
Wear (teeth, wings)
Annual growth rings
Colour change
Physiological measures (ovary development, amount of waste products accumulated in tissues).

Net rate of increase and death rate.

Type I - For younger individual mortality rate is low, dying an increased rate as individuals get older.
Type II - the mortality factors effect individuals evenly at different ages. Very unusual.
Type III - Mortality if the juvenile is extremely high. Once it gets to a certain age it gets less.

Cohort life table - dynamic, follows a cohort over time. follow an organisms through life.
Static life table - snapshot of the population at one time.

The highest mortality rate.

k-factor (immigration is a k-factor).

Killing power.

No.