Population Dynamics (4.1) State Standard SB4C. Relate environmental conditions to successional changes in ecosystems.

A C B

The number of organisms per unit area Chapter 4 Population Ecology 4.1 Population Dynamics Population Characteristics (AKA Demographics) Population Density The number of organisms per unit area Spatial Distribution Dispersion is the pattern of spacing of a population.

Demography – the study of human population size, density, distribution, movement, and birth/death rates.

The number of organisms per unit area Chapter 4 Population Ecology 4.1 Population Dynamics Population Characteristics Population Density The number of organisms per unit area Spatial Distribution Dispersion is the pattern of spacing of a population. Uniform – equally dispersed – territorial animals

The number of organisms per unit area Chapter 4 Population Ecology 4.1 Population Dynamics Population Characteristics Population Density The number of organisms per unit area Spatial Distribution Dispersion is the pattern of spacing of a population. Uniform – equally dispersed – territorial animals Clumped – groups – herding animals

The number of organisms per unit area Chapter 4 Population Ecology 4.1 Population Dynamics Population Characteristics Population Density The number of organisms per unit area Spatial Distribution Dispersion is the pattern of spacing of a population. Uniform – equally dispersed – territorial animals Clumped – groups – herding animals Random – no pattern – usually based on resources

Chapter 4 Population Ecology 4.1 Population Dynamics Population Characteristics Cont’d Population Range Common dolphin A species might not be able to expand its population range because it cannot survive the abiotic conditions found in the expanded region. Pupfish

Demography – the study of human population size, density, distribution, movement, and birth/death rates.

Chapter 4 Population Ecology 4.1 Population Dynamics Population-Limiting Factors There are two categories of limiting factors—density-independent factors and density-dependent factors.

Density-Independent Factors (generally abiotic) Chapter 4 Population Ecology 4.1 Population Dynamics Population Limiting Factors Cont’d Density-Independent Factors (generally abiotic) Any factor in the environment that does not depend on the number of members in a population per unit area is a density-independent factor. Weather events Fire Human alterations of the landscape Air, land, and water pollution

Density-Dependent Factors Chapter 4 Population Ecology 4.1 Population Dynamics Population Limiting Factors Cont’d Density-Dependent Factors Any factor in the environment that depends on the number of members in a population per unit area is a density-dependent factor. Biotic factors Disease Population Biology Competition Parasites

Growth Rate is affected by… Limiting Factors Chapter 4 Population Ecology Population Growth Rate The population growth rate (PGR) explains how fast a given population grows. Growth Rate is affected by… Limiting Factors

Growth Rate is affected by… Limiting Factors Natality (# of births) Chapter 4 Population Ecology Population Growth Rate The population growth rate (PGR) explains how fast a given population grows. Growth Rate is affected by… Limiting Factors Natality (# of births)

Growth Rate is affected by… Limiting Factors Natality (# of births) Chapter 4 Population Ecology Population Growth Rate The population growth rate (PGR) explains how fast a given population grows. Growth Rate is affected by… Limiting Factors Natality (# of births) Mortality (# of deaths)

Growth Rate is affected by… Limiting Factors Natality (# of births) Chapter 4 Population Ecology Population Growth Rate The population growth rate (PGR) explains how fast a given population grows. Growth Rate is affected by… Limiting Factors Natality (# of births) Mortality (# of deaths) Immigration (# of individuals entering)

Growth Rate is affected by… Limiting Factors Natality (# of births) Chapter 4 Population Ecology Population Growth Rate The population growth rate (PGR) explains how fast a given population grows. Growth Rate is affected by… Limiting Factors Natality (# of births) Mortality (# of deaths) Immigration (# of individuals entering) Emigration (# of individuals exiting)

Exponential Growth Model Chapter 4 Population Ecology 4.1 Population Dynamics Population Growth Rate Cont’d Graph shows a J-shaped Curve! Exponential Growth Model Exponential growth occurs when the growth rate is proportional to the size of the population. All populations grow exponentially until some limiting factor slows the population’s growth.

Chapter 4 Population Ecology Population Growth Rate Cont’d Logistic Growth Model The population’s growth slows or stops following exponential growth, at the environment’s carrying capacity. Carrying capacity is the largest # of individuals an environment can support. Graph shows an S-shaped Curve!

Chapter 4 Population Ecology 4.1 Population Dynamics Population Growth Rate Cont’d A population stops increasing when natality is less than mortality or when emigration exceeds immigration. Carrying capacity is limited by the energy, water, oxygen, nutrients, & space, as well as other limiting factors.

Chapter 4 Population Ecology

Chapter 4 Population Ecology 4.1 Population Dynamics Reproductive Patterns Species of organisms vary in the number of births per reproduction cycle, in the age that reproduction begins, and in the life span of the organism.

An r-strategist is generally a small organism. Chapter 4 Population Ecology 4.1 Population Dynamics Reproductive Patterns Cont’d The rate strategy, or r-strategy, is an adaptation for living in an environment where fluctuation in biotic or abiotic factors occur. An r-strategist is generally a small organism. Short life span Produces many offspring

A k-strategist is generally a larger organism. Chapter 4 Population Ecology 4.1 Population Dynamics Reproductive Patterns Cont’d The carrying-capacity strategy, or k-strategy, is an adaptation for living in stable environments. A k-strategist is generally a larger organism. Long life span Produces few offspring

Chapter 4 Population Ecology Chapter Diagnostic Questions What term is used to describe the number of individuals moving into a population? emigration imitation immigration migration A B C D CDQ 1

What is population density? Chapter 4 Population Ecology Chapter Diagnostic Questions What is population density? pattern of spacing of a population in an area number of organisms in an area characteristics of a population manner in which a population grows A B C D CDQ 2

Which is a density-dependent factor? Chapter 4 Population Ecology 4.1 Formative Questions Which is a density-dependent factor? disease fire flooding weather A B C D FQ 1

Which is a density-independent factor? Chapter 4 Population Ecology 4.1 Formative Questions Which is a density-independent factor? competition extreme cold parasites predation A B C D FQ 2

Which factor can limit the carrying capacity of a population? Chapter 4 Population Ecology 4.1 Formative Questions Which factor can limit the carrying capacity of a population? emigration predation available nutrients extreme temperatures A B C D FQ 3

Which type of population growth model does this graph represent? Chapter 4 Population Ecology Chapter Assessment Questions Which type of population growth model does this graph represent? exponential spatial genetic logistic A B C D CAQ 1

Use the graph to explain the growth of the mice population. Chapter 4 Population Ecology Chapter Assessment Questions Use the graph to explain the growth of the mice population. CAQ 3

Chapter 4 Population Ecology Standardized Test Practice The ecologist finds that over a 1000m2 plot of tundra, lemmings tend to concentrate in clumps in drier areas. What is the term for this pattern of spacing? density dispersion logistic spacing spatial distribution A B C D STP 2

It is density-dependent. It is limited by biotic factors. Chapter 4 Population Ecology Standardized Test Practice Brine shrimp are able to survive only in certain lakes that have a very high salt concentration. Which is the correct population characteristic of brine shrimp? It is density-dependent. It is limited by biotic factors. It has a limited spatial distribution. It is randomly dispersed in the environment. A B C D STP 3

Standardized Test Practice Chapter 4 Population Ecology Standardized Test Practice Why does the population growth level off at 10,000? Biotic factors have made survival difficult. The population has reached its carrying capacity. Density-independent factors have slowed the growth of the population. Immigration into the population has reached the maximum limit. A B C D STP 4

Which organism is the best example of a k-strategist? Chapter 4 Population Ecology Standardized Test Practice Which organism is the best example of a k-strategist? wolf grasshopper rabbit whale A B C D STP 5