Population dynamics

Question 1

What is population dynamics?

Answer 1

The changes in the populations of organisms over time

Question 2

What is population size?

Answer 2

the number of individuals of a specific species occupying a given area/volume at a given time

Question 3

What is population density?

Answer 3

The number of individuals of the same species that occur per unit area or volume

Question 4

What is the formula for population density?

Answer 4

D=N/S
N=Total number of individuals in the population
S=Space occupied by the population

Question 5

What is population dispersion?

Answer 5

the pattern of distribution in which a population exists

Question 6

What is the clumped dispersion patter?

Answer 6

A pattern in which individuals in a population are more concentrated in certain parts of the habitat

Question 7

What are the three situations where clumped pattern happens?

Answer 7

1)When suitable living conditions are distributed in patches
2)Mates are easier to locate in groups
3)Limited seed dispersal or asexual reproduction

Question 8

What is random dispersion?

Answer 8

Organisms are distributed unpredictably.

Question 9

Why does random dispersion happen?

Answer 9

Occurs when environmental conditions do not vary greatly within a habitat and when individuals are neither attracted to nor repelled by others of their species.

Question 10

What is uniform dispersion?

Answer 10

Equally spaced throughout a habitat.

Question 11

What is the mark-recapture sampling methd?

Answer 11

A sampling technique used to estimate the population size of a species.

Question 12

How is the mark-recapture method done?

Answer 12

1. A specific number of animals in the natural population is captured, marked, and then released back into the population
2. After a period of time when the marked animals have mixed in with the unmarked animals, another sample is captured.
3. Biologists use the proportion of marked to unmarked animals in the second sample to estimate the size of the entire population

Question 13

What is the mark-recapture formula?

Answer 13

N= Mn/ m
N= total population
M= Total number marked
n= size of second sample
m= number of recaptures

Question 14

What is demography?

Answer 14

the statistical study of population changes over time: birth rates, death rates, and life expectancies

Question 15

What is a survivorship curve?

Answer 15

This displays the survival of individuals over the lifespan of the species.

Question 16

What is population size determined by?

Answer 16

• Births and immigration – which increase population size.
• Deaths and emigration – these decrease population size.

Question 17

What are the abiotic factors?

Answer 17

temperature,
sunlight,
pH,
salinity,
precipitation.

Question 18

What is a factor density dependant?

Answer 18

are ones that affect the population only when it reaches a certain density. These include competition, disease, parasitism and predation

Question 19

What are factors density independent?

Answer 19

factors that will control populations no matter what the density of it is. They include sunlight, temperature, water and natural disasters.

Question 20

What is the J-shaped growth curve?

Answer 20

Shows exponential population growth under ideal conditions with plenty of resources and limited competition.
- population continues to grow until environmental resistance take effect
- At that point the population will crash
-

Question 21

What is the S-shaped growth curve?

Answer 21

Exponential growth is only possible for a short period of time because as the population grows resources are depleted and the growth rate slows and will eventually plateau off.

Question 22

What are the types of the survivorship curve?

Answer 22

Type I: K-selected species. high survival rate in early life at the end mortality increases dramitically
Type II: shows the middle ground with a more or less constant mortality rate throughout the organisms life
Type III: r-selected species. very low survival rates after birth. Very few individuals make it into later life.

Question 23

What are the charcateristics of K-strategies?

Answer 23

• Large size
• Large offspring with high survivial rate
• Parental care
• Mature late
• Reproduce slowly
• Regulated by internal factors
• Long lifespam
• Specialists
• Predator/ higher trophic levels

Question 24

What are the charcteristics of R-strategies?

Answer 24

• Small size
• Small offsrping low survival rate
• No parental care
• Mature young
• Reproduce quickly
• Regulated by external factors
• Generalists
• Prey/ lower trophic levels