Chap 20

Question 1

Population Density

Answer 1

Is defined as the # of individual organisms (N) in a given area (A) or volume (V).
• [Dp =N/A or Dp =N/V]

Question 2

Growth rate (gr)

Answer 2

The change in the number of individuals in a population (^N) over a specific time frame (^t)

(Population crash and explosion for decrease and increase)

Question 3

Three distribution patterns

Answer 3

Distribution patterns influenced by the distribution of resources in a habitat and the interactions among members of population/community

-3 types

Question 4

3 distribution:

Answer 4

• uniform: artificial populations like orchards
• random: resources are abundant and populations don’t compete
• clumped: common as members are closer together for resources

Question 5

Growth equation

Answer 5

gr= ^N/^t

Individuals over time

Question 6

Per capita growth

Answer 6

Can be determined by calculating the change in the number of individuals(^N) relative to N (original individuals)

• {gr= ^N/N or Nfinal-N/N}

Question 7

Factors that affect population growth

Answer 7

1) biotic factors
2) abiotic factors
3) limiting factors

Question 8

Biotic Potential (r)

Answer 8

The highest possible “cgr” population

• # of offspring per reproductive cycle
• # of offspring that survive long enough to reproduce
• age of reproductive maturity
• life span of individuals

Question 9

Exponential Growth Pattern

Answer 9

Brief lag phase followed by a steep increase in the growth curve. (J-shaped curve)

Ex) bacteria growth

Question 10

Logistic Growth patterns

Answer 10

An s-shaped curve (sigmoidal)

Question 11

Carrying Capacity (K)

Answer 11

Green line running through a curve
•theoretical maximum of population size that environment can sustain over time.
~without depleting resources

Question 12

Density-dependent factors

Answer 12

Are BIOTIC

•increase with the density of a population

Question 13

Density-independent factors

Answer 13

Are ABIOTIC and include harsh weather (drought flood fires)

•limit growth of a population regardless of density

Question 14

Environmental resistance

Answer 14

Interacting limiting factors

•prevents a population from growing at its biotic potential and determined the carrying capacity of the habitat

Question 15

R-selected strategies

Answer 15

Species that REPRODUCE close to their biotic potential (r) 
•early reproductive age
•short life span
•no parental care
Ex) algae

Question 16

K-selected strategies

Answer 16

Populations that live close to the carrying capacities (K) of their habitat

•few offspring per cycle
•parental care
•pinger life span
Ex) bison

Question 17

Population types

Answer 17

Open system: immigration vs emigration

Closed system: nothing is added or removed from the environment

Question 18

1) competition

Answer 18

• intraspecific

* interspecific

Question 19

intraspecific

Answer 19

Competition for limited resources among members of the SAME species

Question 20

Interspecific

Answer 20

Competition between 2 OR MORE populations for resources (light, space)

-can’t share niches

Question 21

2) predator and prey

Answer 21

-producer consumer interaction
•peak for predators = crash for prey
~next year they will crash to restart

Question 22

3) symbiotic relationships

Answer 22

• mutualism(++)
• commensalism
• parasitism (-+)

Question 23

4) succession

Answer 23

•pioneer community first to colonize
•climax community becomes stable
A) primary succession: ongoing eras
B) secondary succession: disturbance (fire)

Question 24

Primary succession and secondary

Answer 24

1) NO SOIL. An event occurs that changes structure if a community
2) soil REMAINS. Recolonization of Ana area after disturbances

Question 25

Sustainability

Answer 25

The concept of living in a way that meets out needs without compromising health of future generations or planet

Question 26

Age pyramid

Answer 26

Are tools that demographers use to help them assess a populations potential for growth. (Cgr)
•shows % of males and females in separate categories