Population Ecology Flashcards
1
Q
ecology
A
study of how living organisms and the physical environment interact
2
Q
Biotic factor
A
interactions among organisms
3
Q
Abiotic factors-
A
interactions between organisms and the non living environment
4
Q
examples of abiotic factors
A
Precipitation
Temperature
Wind
5
Q
Population
A
group of individuals of same species living in
the same area
6
Q
Community
A
groups of populations of diff species living in same area
7
Q
Ecosystem
A
interrelations between organisms in a community and
their physical environment
8
Q
Biosphere
A
all regions of the earth that contain living things
9
Q
habitat
A
place where an organism lives (Includes organisms as well as physical/ chemical characteristics)
10
Q
Niche
A
all biotic and abiotic resources in an environment
used by an organism–When an organism is in a niche, certain resources are consumed
or certain qualities of environment are changed by the organism
11
Q
Population ecology considers….
A
considers both the
number of individuals of a species and dynamics of population
12
Q
Population size is measured by ….
A
population density
13
Q
population density
A
# of individuals of a species per unit of area or volume (varies from season to season)
14
Q
delta
A
change in
15
Q
rMax
A
ideal r/max per capita growth rate of population
16
Q
rate equation
A
dY/dT
17
Q
Population growth
A
dN/dt=B-D
18
Q
exponential growth
A
dN/dt=rMaxNd
19
Q
logistic growth
A
dN/dt=rMaxN((k-N)/k)
20
Q
dY
A
amount of change
21
Q
t
A
time
22
Q
B
A
birth rate
23
Q
D
A
death rate
24
Q
N
A
population size
25
K
carrying capacity
26
Increase in pop size
births and immigration
27
decrease in pop size
deaths and emigration
28
Birth rate, or B
(“natality”)- average per capita (rates per individual)
| birth rate --b/N
29
Death rate, or D
(“mortality”)- average per capita death rate--d/N
30
r expressed in
decimal
31
r
B-D
32
If B is greater than D
r is positive and the population is increasing
33
If B is less than D
r is negative and the population is decreasing
34
When B and D are equal
r is 0 and the population is constant
35
What is it called when the population is constant?
0 population growth
36
intrinsic rate of increase (rmax)
The maximum rate at which a population of a given species could increase
under ideal conditions (when resources are abundant and population density
is low)
37
large v small species intrinsic rate
large-Smaller, small-larger (bacteria),
38
Under optimal conditions, the reproductive rate of a population would have
....
exponential growth (j shaped curve)
39
why can't organisms reproduce indefinitely at their intrinsic rate of
increase?
environment sets limits
40
ex of environmental limits
food, water, shelter, competition
41
Over time, rate of population growth may decrease to nearly zero-
population levels out when
....
environmental limits reached
42
Carrying capacity (K)
represents the largest population that can be
maintained for an indefinite period by a
particular environment
43
When does K change?
in response to environmental changes- ex- if there is a drought, carrying capacity for animals in the area decrease; if abundance of food, it'll increase
44
logistic population growth
realized population growth--Curve of graph is an S-curve- When N is small, rate of population growth higher; As N reaches K, growth rate declines
45
when is pop growth rate highest
halfK?
46
population crash
abrupt decline
47
population cycles at k
Populations rarely stabilize at K- may temporarily rise above K, then drop down to or below K
48
what happens if a population overshoots K
population crash
49
Density-dependent factors
change in population density alters how an
| environmental factor affects population
50
ex of density dependent factor
predation, disease, competition
51
which factor has less of an effect on a small population as compared to a large one
density dependent factor
52
Density-independent factors
environmental factors, usually abiotic, that
affect the size of population-
irrespective of density
53
ex of DI factors
random weather events such as frost, blizzard, hurricane
54
Life history traits
ways in which a species reproduces and survives
55
r- selected species-
traits that contribute to high population growth rate, reproduce quickly at their r
56
traits of r selected species
Small body size, short life span, no parental care
57
two extremes of life history traits
r selected and k selected
58
nickname r selected species
Called opportunist species- quickly inhabit an area, reproduce, die
59
Ex r selected species
Ex- weeds, mosquitoes
60
K- selected species-
traits that allow the population to function best at the K
61
traits of k selected species
Long life spans with slow development, late reproduction, large
body size, low reproductive rate, parental care
Found in constant stable environments
62
ex k selected species
humans, redwood trees, owls
63
Life tables-
show mortality and survival data of a population at different
times during their lifetime
64
Type I + ex
young have high probability of surviving, but with increasing
age, probability of surviving
decreases more rapidly ex-humans
65
Type II + ex
probability of death is equally likely across all age groups,
resulting in linear decline of survivorship
Ex- some lizards and rodents
66
Type III + ex
probability of mortality is highest early in life, and
probability of survival increases with increasing ages
Oysters- have free swimming larvae that are easily eaten
67
human population prediction, current
currently J with a slight dip for the plague --Even though population is increasing, the world growth rate is slowly
declining- predicted that the point of zero population growth (r= 0) will
occur toward the end of the 21st century
68
Age structure
number and proportion of people at each age in a
| population
69
Age structure diagram
shows number of males and females at each
| age, from birth to death
70
countries w high birth rate diagrams
Countries with high birth rates have pyramid-shaped diagram,
meaning that the probability of
future growth is great
71
stable population diagrams
tiers of equal width
72
shrinking population diagram
Shrinking population has prereproductive group smaller than
| postreproductive group
73
do all countries have same growth rate
no
