Lecture 7

Question 1

Distribution:

Answer 1

• Geographic area where individuals of a species occur
• Can map out

Question 2

Abundance:

Answer 2

• Number of individuals in a given area
• can be reported as population size (# of individuals), or density (# of individuals per unit area)
• an vary throughout a species’ range

Question 3

Population:

Answer 3

• Group of interacting individuals of the same species living in a particular area
• Interactions within populations include sexual reproduction and competition

Question 4

Individuals:

Answer 4

• products of a single fertilization

Question 5

2 Types of Individuals:

Answer 5

1. Genet
2. Ramet

Question 6

Genet:

Answer 6

• one unit
• cluster
• Ex. the aspen grove

Question 7

Ramet:

Answer 7

• If members of a genet are independent physiologically
• units within genet

Question 8

Estimating Abundance and Distribution:

Answer 8

• Complete counts of individual organisms in a population are often difficult or impossible
• Several methods are used to estimate the actual abundance or absolute population size

Question 9

Area-based Counts:

Answer 9

• Used most often to estimate the abundance of immobile organisms

Question 10

Quadrants:

Answer 10

• Sampling areas of specific size, such as 1 m2
• Individuals are counted in several quadrats; the counts are averaged to estimate population size.

Question 11

Distance Methods:

Answer 11

• distances of individuals from a line or point are converted into estimates of abundance

Question 12

Line Transects:

Answer 12

• The Observer travels along the line and counts individuals and their distance from the line

Question 13

Mark-recapture Studies:

Answer 13

• Used for mobile organisms
• A subset of individuals is captured and marked or tagged, then released
• Tag should not affect their performance in life

Question 14

Ratio for Mark-recapture studies:

Answer 14

marked/ total population : recaptured marked / total caught

Question 15

Relative Population Size:

Answer 15

• Number of individuals in one time period or place relative to the number in another
• Estimates are based on data presumed to be related to absolute population size
• Interpretation of relative population size can be tricky

Question 16

Distribution and Abundance:

Answer 16

1. The distribution and abundance patterns of species and populations vary in their spatial extent across the landscape
2. The distributions and abundances of organisms are limited by habitat suitability, historical factors, and dispersal

Question 17

The distribution and abundance patterns of species and populations vary in their spatial extent across the landscape:

Answer 17

• Not all habitat within a range is suitable: resulting in patchy distributions
• This can operate at different spatial scales
• At large scales, climate may dictate the locations of populations
• At small scales, soils, topography, other species, etc., can determine patchiness

Question 18

Dispersion:

Answer 18

• spatial arrangement of individuals within a population
• Often results from the distribution of resources
• Interactions can influence dispersion- individuals may repeal or attract others

Question 19

Types of Dispersion:

Answer 19

1. Regular
2. Random
3. Clumped

Question 20

Regular Dispersion:

Answer 20

• Individuals are evenly spaced (checkerboard)

Question 21

Random Distribution:

Answer 21

• individuals scattered randomly

Question 22

Clumped Distribution:

Answer 22

• the most common pattern

Question 23

Random or Clumped Dispersion results from…

Answer 23

• short dispersal distances

Question 24

Competiton:

Answer 24

• results in the regular dispersion of some species

Question 25

Species Distribution Modelling:

Answer 25

- Predicts a species’ distribution based on conditions at locations the species is known to occupy

Question 26

Habitat Rules for Each Species:

Answer 26

- describes environmental conditions where it was most likely to be found

Question 27

Biotic Features:

Answer 27

- Organisms are affected by herbivores, predators, competitors, parasites, and pathogens

Question 28

Cooperative Breeding:

Answer 28

- Young birds postpone breeding and instead help their parents raise more offspring - In high-quality territories - Results in clumped dispersion - Advantageous when high-quality territories are scarce -If high-quality territories are abundant, cooperative breeding is not favoured

Question 29

Disturbance:

Answer 29

- Events that kill or damage some individuals, create opportunities for other individuals to grow and reproduce - Some species' distribution depends on disturbance

Question 30

Historical Factors:

Answer 30

- Evolutionary history and geologic events affect the modern distribution of species

Question 31

Dispersal Limitation:

Answer 31

- Can prevent species from reaching areas of suitable habitat - Species vary in their ability to disperse

Question 32

Migration:

Answer 32

- involves round-trip movement in response to seasonal variations in resources

Question 33

Metapopulation:

Answer 33

- A set of spatially isolated populations linked by the dispersal of individuals or gametes - Characterized by repeated extinctions and colonizations of small individual populations, but the metapopulation persists

Question 34

Habitat Fragmentation:

Answer 34

- Large tracts of habitat are converted to isolated patches, resulting in a metapopulation structure - As patches get smaller and more isolated, colonization decreases and the extinction rate increases

Question 35

Isolation by Distance Definition:

Answer 35

- when patches are too far apart

Question 36

Isolation by Distance May Affect:

Answer 36

- the chance of extinction - a patch that is near an occupied patch may receive immigrants repeatedly - the chance of extinction - a patch that is near an occupied patch may receive immigrants repeatedly

Question 37

Patch Size:

Answer 37

- small patches may be hard to find and have high extinction rates

Question 38

Rescue Effect:

Answer 38

- high rates of immigration that protect a population from extinction

Question 39

Geographic Range:

Answer 39

- The entire geographic region over which a species is found - There is great variation in species ranges the geographic ranges of many species are not well-known - Many tropical plants have small ranges - In 1978, 90 new species were discovered - includes areas occupied during all life stages