Chapter 45 bio notes (textbook)
Quiz 5: Ch. 18 (Speciation). These include:
Sections 18.1, 18.2, 18.3, 18.6 (intro, 18.6a, 18.6b), 18.7 (intro, 18.7a, 18.7b), and 18.8
(intro, 18.8a, 18.8b, 18.8c).
= quiz 6
Ch. 18, section 18.9 (intro, 18.9a, 18.9b, 18.9c), 18.10, and Ch 45 (we're starting
Ecology!), sections 45.1 and 45.2a and 45.2b.
The quiz covers readings in Ch. 45: 45.2 [45.2c, 45.2d, 45.2e, 45.2f, 45.2g]; 45.3 [Intro,
45.3a - only have to know in very general terms what a life table summarizes, 45.3b]
45.4 [Intro, 45.4a, 45.4b, 45.4c].
• Models of Population Growth - there is math in this section - Ch 45 [45.5 (Intro,
45.5a, 45.5b)]. Please note: logistic growth is simply a derivation of exponential
• Population regulation: Ch 45 [45.6 (Intro, 45.6a, 45.6b, 45.6c, 45.6d)].
45.1 The Science of Ecology
- Ecology can divided into 4 levels of organization
1. Organismal ecology: researchers study organisms to determine the gentic,
biochemical, physiological, morphological, and behaviourial adaptations to
the Abiotic environment.
2. Population ecology: focus on the groups of individuals of the same species tht
live together. Pop ecologists study the size and other characteristics of pops
change in space and time.
3. Community ecology: biologists examine pops of species, analyzing how
predators, competition, and environmental disturbances influence a
community’s development, organization, and structure.
4. Ecosystem ecology: explore how nutrients cycle and energy flows b/w biotic
components of an ecological community* and the biotic environment.
- Mathematical models express hypotheses about ecological relationships and
different variables, allowing researchers to manipulate the model and
document resulting change.
- Experimental and control treatments are necessary b/c they allow ecologists
to separate cause and effect.
45.2 a Geographic Range: Boundaries of Distribution - Geographic range (every pop has it and there is a wide range): the overall
spatial boundaries w/i which it lives.
- Habitant ( every pop occupies one) : the specific environment in which it
lives, as characterized by its’ biotic and Abiotic features
- Other characteristics such as size, distribution in space, age structure are also
45.2 b Population size and density: number of individuals per unit area
- Population size: is the # of individuals comprising the pop at a specified
- Population density: is the number of individuals per unit area or per unit
volume of habitat.
- A lower pop density means tht individuals have a greater access to resources
such as sunlight and water.
- The capture-mark-recapture technique assumes:
1. A mark has no effect on individual’s survival
2. Marked and unmarked individuals mix randomly.
3. There is no migration throughout the estimation period
4. Marked and unmarked individuals are equally likely to be caught.
45.2c Population Dispersion :the distribution of individuals in space
- populations can vary in their dispersion: clumped, uniform and random
- dispersion and animal dispersion can vary through time in response to natural
1. Clumped Dispersion(common ) : happens in 3 different situation 1. Suitable
conditions often patchily distributed (ex. pasture plants), 2. Pops of some social
animals are clumped together b/c it is easier to find mates, 3.when species
reproduce by asexual clones tht remain attached to parents.
2. Uniform Dispersion: when individuals repel one another b/c of shortage in
resources. Territorial behaviour can produce uniform dispersion.
3. Random Dispersion: when environmental conditions do not vary much w/i a
habitant( species are not attracted or repelled)
45.2d Age structures : # of individuals of different ages
-all pops have an age structure: a statistical description of the relative #s of ini of
- Pops grow as the young mature and reproduce.
45.2e Generation Time: Average Time b/w birth and death
- Generation time is also an characteristic tht influences a pop’s growth. - Generation Time: the average time between the birth of an organism and birth of
45.2f Sex ratio: Females: Males
- The # of males in a pop of mammals has little impact on the pop growth b/c
females bear the weight of pregnancy thus limiting pop growth.
- Interesting fact: male sea horses give birth.
45.2g Proportion reproducing: incidence of reproducing ini in a pop
- pop ecologists try to determine the proportion of the pop tht are reproducing.
- Pop growth : birth and immigration ( movements of organisms into pop)
- Pop decline: deaths and emigration(organisms leaving)
- Demography: the statistical study of the processes tht change a pop’s size
and density through time.
- Demography is used to predict the pop’s future pop growth, develop plans to
save endangered species.
45.3 a (refer only to the table 45.1
45.3b Surviving Curves: Timing of Deaths of ini in a pop
Survivorship curves: displays the rate of survival for ini over the species’ average
- 3 main SCs
1. Curves reflect high survivorship curves until late in life (pg. 1119) :
typical in large animals tht produce few young and provide them with
extra care for the 1 year until they learn to fend for themselves.