Unit 3 - Populations Flashcards
1
Q
specialists
A
smaller range of tolerance or narrower ecological niche makes them more prone to extinction
- specific food requirements
- less ability to adapt to new conditions
2
Q
generalists
A
larger range of tolerance, broader niche makes them less prone to extinction and more likely to be invasive
- broad food requirements
- high adaptibility
3
Q
K-selected species (quality)
A
- large
- stable environment
- few offspring per reproduction event, high parental care
-reproduce many times - live in stable environments
- long life spans
- density dependent
- low biotic potential = slow pop. growth rate
- competition for resources is relatively high
4
Q
r-selected species (quantity)
A
- small
- unstable environment
- density independent
- have many offspring, little to no parental care
- may reproduce only once
- shorter lifespan, quick to sexual maturity = high biotic potential = high pop. growth rate
- more likely to be invasive
- better suited for rapidly changing env. conditions
- competition for resources is relatively low
5
Q
biotic potential
A
low biotic potential (rep. rate) = hard for pop. to recover after a disturbance (env. change)
6
Q
r-selected species tend to be
A
high biotic potential
7
Q
k-selected species tend to be
A
low biotic potential
8
Q
survivorship curves: faster drop in line
A
quicker die off individual
9
Q
survivorship curves: slower drop in line
A
longer avg. lifespan
10
Q
survivorship curves
A
line that shows survival rate of a cohort (group of same aged individuals) in a pop. from birth to death
11
Q
type I
A
- mostly K-selected
12
Q
type I - early life
A
- high survivorship early in life due to high parental care
13
Q
type I - midlife
A
- high survivorship in midlife due to large size and defensive behavior
14
Q
type I - late life
A
- rapid decrease in survivorship in late life as old age sets in
15
Q
type II
A
- in between r & K
- steadily decreasing survivorship throughout life
16
Q
type III
A
- mostly r-selected
17
Q
type III - early life
A
- high mortality (low survivorship) early in life due to little to no parental care
18
Q
type III - midlife
A
- few make it to midlife; slow, steady decline in survivorship in midlife
19
Q
type III - late life
A
- even fewer make it to adulthood; slow decline in survivorship in old age
20
Q
carrying capacity (K)
A
the max number of individuals in a population that an ecosystem can support
21
Q
what is carrying capacity based on
A
based on limiting resources
22
Q
limiting resources
A
- highest population size of an ecosystem can support based on limiting resources
23
Q
overshoot
A
when a population briefly exceeds carrying capacity
24
Q
consequence of overshoot
A
resource depletion
- ex: overgrazing in deer
25
die-off/die-back
sharp decrease in population size when resource depletion (overshoot) leads to many individuals dying
26
pop. characteristics: size
- total number of individuals in a given area at a given time
- larger = safer from population decline
27
pop. characteristics: density
- number of individuals in an area
- high density = high competition, possibility for disease outbreak or depleting of food source
28
pop. characteristics: distribution
- how individuals in population are spaced out compared to each other
- random (trees)
- uniform (territorial animals)
- clumped (herd/group animals)
29
pop. characteristics: sex ratio
- ratio of males to females closer to 50:50, the more ideal for breeding (usually)
- die off bottleneck effect can lead to skewed sex ratio, limiting pop. growth
30
density dependent factors
- tend to be biotic, have a strong influence when the number of organisms per unit area reaches a certain level
- factors that influence population growth based on size
31
density independent factors
- tend to be abiotic, have an effect on all populations, regardless of size or density
- factors that influence population growth independent of their size
32
biotic potential
- max potential growth rate, with no limiting resources
- may occur initially, but limiting resources (competition, food, disease, predators) slow growth, and eventually limit population to carrying capacity
33
age cohorts
groups of similarly aged individuals
34
0-14 years old
pre- reproductive
35
15-45 years old
reproductive age
36
46+ years old
post reproductive age
37
extreme pyramid
- expanding rapidly
- rapid growth
- ex: guatemala, nigeria, saudi arabia
38
less extreme pyramid
- slow stable growth
- expanding slowly
- ex: US, Australia, Canada
39
house
- stable
- little to no growth
- ex: spain, portugal, greece
40
inverted pyramid
- declining population
- ex: germany, bulgaria, italy
41
total fertility rate (TFR)
- average number of children a women in a population will bear throughout her lifetime
- higher TFR = higher birth rate, higher population growth rate
42
replacement level fertility
the TFR required to offset deaths in a population and keep population size stable
43
what is the replacement level fertility in developed countries
- 2.1 (replace mom and dad)
44
what is the replacement level fertility in underdeveloped countries
- higher than 2.1 due to higher infant mortality
45
infant mortality rate (IMR)
- number of deaths of children under 1 year per 1000 people in a population
46
IMR in lower developed countries
- higher due to lack of access to healthcare, clean water, enough food
47
higher IMR = ___ TFR
higher IMR = higher TFR due to families having replacement children
48
factors in IMR decline
1. access to clean water
2. access to healthcare (hospitals, vaccines)
3. more reliable food supply
49
factors that affect the TFR: development
- more developed or wealthy nations have a lower TFR than lower developed countries
50
why do developed countries have lower TFR
- more educational access for women
- more economic opportunity for women
- high access to family planning and contraceptives
- later age of first pregnancy
- less need for children to provide income through ag. labor
51
factors that affect the TFR: gov. policy
- can play a huge role in fertility by coercive (forceful) or noncoercive (encouraging) policies
- forced or voluntary sterilization
- chinas 1 (now 2) child policy
- tax incentives to have fewer children
- microcredits or loans to women without children to start business
52
malthusian's theory
- earth has a human carrying capacity probably based on food production
- human population growth is happening faster than growth of food production
- humans will reach a carrying capacity limiting by food
53
growth rate (r)
% increase in a population (usually per year)
54
crude birth rate (CBR)
births per 1000 people
55
crude death rate (CDR)
death per 1,000 people
56
calculating growth rate
= (CBR - CDR) / 10
- growth rate is always expressed as a %
57
doubling time (rule of 70)
- the time it takes (in years) for a population to double is equal to 70 divided by the growth rate
58
doubling time calculations
number of years to double = 70/r (where r is a %, not a decimal)
59
industrialization
the process of economic and social transition from an agrarian economy to an industrial one (manufacturing based)
60
demographic transition model
- a model showing how a nation's population, birth, and death rate are historically correlated when transitioning from agrarian to industrialized
61
stage 1 of DTM - preindustrial
- high birth and death rate
- high IMR and death rate due to lack of access to clean water, stable food supply, and healthcare
- high TFR due to lack of access to education for women, contraceptives
- little to no growth due to CBR & CDR balancing each other out
- virtually, no country is in stage 1
62
stage 2 of DTM - industrialized/developing
- modernizations bring access to clean water, healthcare, stable food supply
- IMR & CDR decline
- TFR remains high due to lack of ed. for women, contraceptives, etc.
-rapid growth due to high CBR and declining CDR
- short life expectancy
63
stage 3 of DTM - industrialized/developed
- modernized economy and society increase family income
- TFR declines significantly due to more educational opportunities for women, delayed age of marriage and first child
- access to family planning and contraceptives
- slowing growth rate as CBR drops closer to CDR
- long life expectancy
- high literacy rate
64
stage 4 of DTM - highly developed
- highly modernized countries that are very affluent
- TFR declines even further as families become more wealthy and spend even more time on educational and career pursuits
- family planning and contraceptives
- CBR drops lower than CDR and growth becomes negative
- longest life expectancy
65
population momentum calculations
r = (b + i) - (d + e)
- r = population growth rate
- b = birth rate
- i = immigration rate
- d = death rate
- e = emigration rate
66
density dependent examples
space, water, nutrients/food, shelter, competition, predation, disease, parasitism
67
density independent examples
natural disaster, temperature, sunlight, human activities, physical characteristics, behaviors
