Lecture 7 Flashcards
1
Q
Distribution:
A
- Geographic area where individuals of a species occur
- Can map out
2
Q
Abundance:
A
- 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
3
Q
Population:
A
- Group of interacting individuals of the same species living in a particular area
- Interactions within populations include sexual reproduction and competition
4
Q
Individuals:
A
- products of a single fertilization
5
Q
2 Types of Individuals:
A
- Genet
- Ramet
6
Q
Genet:
A
- one unit
- cluster
- Ex. the aspen grove
7
Q
Ramet:
A
- If members of a genet are independent physiologically
- units within genet
8
Q
Estimating Abundance and Distribution:
A
- 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
9
Q
Area-based Counts:
A
- Used most often to estimate the abundance of immobile organisms
10
Q
Quadrants:
A
- Sampling areas of specific size, such as 1 m2
- Individuals are counted in several quadrats; the counts are averaged to estimate population size.
11
Q
Distance Methods:
A
- distances of individuals from a line or point are converted into estimates of abundance
12
Q
Line Transects:
A
- The Observer travels along the line and counts individuals and their distance from the line
13
Q
Mark-recapture Studies:
A
- Used for mobile organisms
- A subset of individuals is captured and marked or tagged, then released
- Tag should not affect their performance in life
14
Q
Ratio for Mark-recapture studies:
A
marked/ total population : recaptured marked / total caught
15
Q
Relative Population Size:
A
- 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
16
Q
Distribution and Abundance:
A
- The distribution and abundance patterns of species and populations vary in their spatial extent across the landscape
- The distributions and abundances of organisms are limited by habitat suitability, historical factors, and dispersal
17
Q
The distribution and abundance patterns of species and populations vary in their spatial extent across the landscape:
A
- 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
18
Q
Dispersion:
A
- spatial arrangement of individuals within a population
- Often results from the distribution of resources
- Interactions can influence dispersion- individuals may repeal or attract others
19
Q
Types of Dispersion:
A
- Regular
- Random
- Clumped
20
Q
Regular Dispersion:
A
- Individuals are evenly spaced (checkerboard)
21
Q
Random Distribution:
A
- individuals scattered randomly
22
Q
Clumped Distribution:
A
- the most common pattern
23
Q
Random or Clumped Dispersion results from…
A
- short dispersal distances
24
Q
Competiton:
A
- results in the regular dispersion of some species
25
Species Distribution Modelling:
- Predicts a species’ distribution based on conditions at locations the species is known to occupy
26
Habitat Rules for Each Species:
- describes environmental conditions where it was most likely to be found
27
Biotic Features:
- Organisms are affected by herbivores, predators, competitors, parasites, and pathogens
28
Cooperative Breeding:
- 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
29
Disturbance:
- Events that kill or damage some individuals, create opportunities for other individuals to grow and reproduce
- Some species' distribution depends on disturbance
30
Historical Factors:
- Evolutionary history and geologic events affect the modern distribution of species
31
Dispersal Limitation:
- Can prevent species from reaching areas of suitable habitat
- Species vary in their ability to disperse
32
Migration:
- involves round-trip movement in response to seasonal variations in resources
33
Metapopulation:
- 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
34
Habitat Fragmentation:
- 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
35
Isolation by Distance Definition:
- when patches are too far apart
36
Isolation by Distance May Affect:
- 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
37
Patch Size:
- small patches may be hard to find and have high extinction rates
38
Rescue Effect:
- high rates of immigration that protect a population from extinction
39
Geographic Range:
- 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
40
