lu4 population growth and life table (final)

Question 1

Population definition

a group of…

Answer 1

a group of individuals of the same species in
each area (habitat).

Question 2

Ecology definition

organisms

Answer 2

the study of how organisms interact with each
other and their environment.

Question 3

Population ecology definition
s&d o p

Answer 3

the branch of ecology that studies the structure & dynamics of populations.

Question 4

The term “population” is interpreted differently in various sciences: (3)

pop eco, human demo, genetics

Answer 4

1. In population ecology - a group of individuals of the same species inhabiting the same area.
2. In human demography - a set of humans in a given area.
3. In genetics - a group of interbreeding individuals of the same species, which is isolated from other groups

Question 5

8 characteristics of a population

AS, 3D, GF/R, M, N, S

Answer 5

1. Size: no. of individuals in the population
2. Density: number of individuals in each area
3. Distribution: the spread of individuals in each area
4. Dispersion: how it spreads to other locations (clump,,
   uniform, or random)
5. Age structure: pre-reproductive, reproductive, postreproductive
6. Natality: birth rate
7. Mortality: death rate
8. Growth forms/ growth rate: r-selected or K-selected

Question 6

2 factors affecting natality & mortality:

ACoP, En

Answer 6

1) Age composition of population
2) Environment
* Not all members of the population are equal in their ability to survive
& reproduce.

Question 7

Density-dependent factor

__ impact as pop ___/___ increase

Answer 7

• Population growth rates are regulated/influenced
• limited by the density of a population.
• Is any factor influencing or limiting population growth
• Greater impact as population size/density increases.

Question 8

5 examples of density-dependent factor

Answer 8

• Competition for space which restrict population growth.
• Limited food supply which restricts reproduction.
• Predators concentrate in area where there is a lot of prey.
• High densities may cause stress, hormone changes & immune
  protection level.
• Diseases

Question 9

what is density-independent factor

Answer 9

• Any factor influencing population regulation that acts to reduce population by the same percentage, regardless of size.
• By chance

Question 10

3 examples of density-independent factor

Answer 10

• Weather
• Climate
• Natural disasters

Question 11

what is biotic Potential (or Growth Rate), r

max rate, pop could……inc, ideal conditions

Answer 11

The biotic potential is the maximum rate at which a population could increase under
ideal conditions.

Question 12

Biotic Potential; 4 rsns WHY each species will have a different biotic potential?

V/FoR/LS/SR

Answer 12

DUE TO:
* variations in the species’ reproductive span (how long an individual is capable of reproducing)
* the frequency of reproduction (how often an individual can reproduce)
-> Semelparous: one reproductive event per lifetime
-> Iteroparous: multiple events per lifetime
* “litter size” (how many offspring are born each time)
* survival rate (how many offspring survive to reproductive age)

Question 13

Exponential Growth

Answer 13

(Continuous population
growth in an unlimited
environment) can be
modeled as exponential
population growth.

Question 14

Density-dependent Growth vs. Exponential Growth

Answer 14

• Populations will not increase forever. Ignoring all interactions with other species (competition, predation, parasites, herbivory), resources will still limit growth - food resources & space resources.
• If exponential growth continued, we would be swimming in several meters of houseflies in just 10 years

Question 15

4 limits to Population Growth

BP, LR,Cp(K), LG(curve)

Answer 15

• Few populations can live up to their biotic potential; = where conditions are ideal, every member has food, shelter, no predators or pathogens in the environment, maximum reproduction
• Over time, the limiting resources of an environment will limit the population growth
• Population size will reach the carrying capacity (K)
• Resulting in Logistic growth (S-curve)

Question 16

(Characteristics of Density-dependent Growth) Carrying capacity =

and what can limit them (2)

Answer 16

the maximum number of
individuals of a species
that can be sustained by an
environment without
decreasing the capacity of
the environment to sustain
that same amount in the
future

Resources will limit growth
- Food and/or Space

Question 17

Population Strategies
r-Strategy Compared to K-Strategy

Answer 17

• r-strategy: high intrinsic growth rates - focuses on reproduction, not on competition with other individuals in the population.
• K-strategy: focuses on population at or near carrying capacity - must be able to compete with other individuals in the population.

Question 18

6 characteristics (each) of contrasting reproductive strategies

Answer 18

• Extrinsically Controlled Growth
  -> r-strategy
  1. Short life
  2. Rapid growth
  3. Early maturity
  4. Many small offspring
  5. Little parental care or protection
  6. Little investment in individual
  offspring
• Intrinsically Controlled Growth
  -> K-strategy
  1. Long life
  2. Slower growth
  3. Late maturity
  4. Fewer large offspring
  5. High parental care and protection
  6. High investment in individual
  offspring

Question 19

r-K scale of reproductive strategy: balancing egg output vs parental care

Answer 19

• oysters = r-strategy
  – produce 500 mil fertilized eggs per year
  – provide no parental care
• great apes = K-strategy
  – produce 1 infant per 5 or 6 years
  – provide extensive parental care

Question 20

life tables

Answer 20

• Show how survival & reproductive rates vary with age,
  population size or life cycle (developmental) stage
• Information about births & deaths is essential to predict
  trends or future population size
• Also provide data for Mortality & Survivorship Curves

Question 21

survivorship curve

Answer 21

• A survivorship curve is a plot of the no. of individuals from a
  hypothetical cohort that will survive to reach different ages
  (data obtained from life table).
• Survivorship curves can vary:
  – among populations of a species
  – between males & females
  – among cohorts that experience different environmental
  conditions
• Survivorship curves – 3 general types

Question 22

3 types of survivorship curves graphs

Answer 22

• type I: high death rate in post-reproductive years (keatas kanan)
• type II: constant mortality rate throughout life span (gradient)
• type III: very high early mortality but the few survivors then live long (stay reproductive) (kebawah kiri)

Question 23

Life Expectancies/ Survivorship Change With Age (I,II,III types)

example
s, mortality rate

Answer 23

• Type I:
  ̶ humans & other large mammals, giant tortoise
  ̶ high mortality when reach old age
  ̶ K-strategy
• Type II:
  ̶ birds (seagull, songbird), small mammals, reptiles
  ̶ probability of death is unrelated to age
• Type III:
  ̶ aquatic organisms that release fertilised eggs,
  invertebrates, plants (annual & perennial)
  ̶ high mortality of very young individuals
  ̶ r-strategy

Question 24

Summary: Population Growth

Answer 24

• It is also important to consider human growth patterns when
  studying the population growth & decline of other species because:
  1. Humans out compete most species for many resource- food, water, land, etc. Thus their carrying capacity is dramatically affected
  2. Increase in human populations cause the amount of toxic to build up (pesticide run off, cargo ship oil spills, acid rain)
  3. Some species get benefits from the growth of human population. eg:
• house sparrows & cockroaches use human shelters for homes
• bacteria & amoebae’s can use humans as an intermediate host intheir life cycle
• lice, thrive in humans
• Thus no matter what the species, humans have an impact of their ability to
  survive and reproduce.