Chapter 4: Population Ecology Essential Questions: EQ: How would changes in populations affect the flow of energy and matter in the ecosystem? EQ: How are populations regulated over time? EQ: How does the growing human population threaten the biosphere? Investigate the relationships among organisms, populations, communities, ecosystems, and biomes.

Click on a lesson name to select. Chapter 4 Population Ecology Section 1: Population Dynamics Section 2: Human Population

Click on a lesson name to select. A laboratory jar containing a population of beetle larvae (mealworms) has reached a stable population size. We decide to add twice as much food per day to the jar, but this turns out to have no effect on population size. What is the most likely explanation?

Click on a lesson name to select. Populations Defined by different __________________ appropriate to the questions being asked Important characteristics: –_______________

Click on a lesson name to select. What is POPULATION DENSITY? The number of individuals of a species per unit area or volume. Three factors can affect population size –number of____________ –number of _____________ –number of individuals that ______________________ __________ the population __________________ (im-uh-gray-shun), the movement of individuals into an area, is another factor that can cause a population to grow. __________________ (em-uh-gray-shun), the movement of individuals out of a population, can cause a population to decrease in size.

_______________________  The number of organisms per unit area 4.1 Population Dynamics Spatial Distribution Chapter 4 Population Ecology  _________________is the pattern of spacing of a population.

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

EQ: How are populations regulated over time?

Population Limiting Factors Environmental factors that restrict population growth. Some limiting factors depend on the size of the population. Other limiting factors affect all populations in similar ways, regardless of the population size.

Warm-up: Population Limiting Factors 1. Imagine a small island that has a population of five rabbits. How might each of the following factors affect the rabbit population? a. climate b. food supply c. predation 2. Now imagine another small island that has a population of 500 rabbits. How would the same factors affect this population? 3. Which of the factors depend on population size? Which factors do not depend on population size?

Population Ecology Population-Limiting Factors 4.1 Population Dynamics  There are two categories of limiting factors__________________________factors and_______________________________. Chapter 4

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

Growth of Aphids Exponential growth Steady population size Peak population size Rapid decline Steady population size Section 5-2 A Density-Dependent Limiting Factor

Density-Independent Factors  Any factor in the environment that does not depend on the number of members in a population per unit area is ________________. Population Ecology  _________________  ______________________________ 4.1 Population Dynamics Chapter 4

Checkpoint! 1. Name 2 types of limiting factors for a population. 2. Of the following factors with the potential to limit growth of a human population, which one is most density-independent? –Mass drowning caused by hurricane flood –Freezing deaths due to a shortage of housing

Population Ecology Population Growth Rate  The _________________________(PGR) explains how fast a given population grows.  The natality of a population is the birthrate in a given time period. 4.1 Population Dynamics Chapter 4

Population Ecology Exponential Growth Model  Exponential growth occurs when the growth rate is _______________to the size of the population.  All populations grow _______________unt il some ____________________slows the population’s growth. 4.1 Population Dynamics Chapter 4

Population Ecology Logistic Growth Model  The population’s growth ___________or ___________followi ng exponential growth, at the population’s_______ _______________ 4.1 Population Dynamics Chapter 4

Population Ecology 4.1 Population Dynamics Chapter 4  A population stops increasing  when the number of births is ________than the number of deaths  when emigration ______________immigration.

Population Ecology Chapter 4

Population Ecology Carrying Capacity  The _____________number of individuals in a species that an ____________________for the long term is the carrying capacity.  Carrying capacity is limited by the___________,___________,__________, and _____________available. 4.1 Population Dynamics Chapter 4

Population Growth can be represented bycharacterized by represented by which cause a Exponential growth Logistic growth Falling growth rate S-shaped curve Limits on growth No limits on growth J-shaped curve Constant growth rate Unlimited resources Concept Map

Checkpoint!!! Which of the following is NOT a condition for a population to reach exponential growth? –presence of unlimited resources –absence of predation and disease –movement of individuals out of a population

Population Ecology Reproductive Patterns  Species of organisms vary  in the number of _____________per reproduction_________  in the __________that reproduction begins  in the _______________of the organism. 4.1 Population Dynamics Chapter 4

Population Ecology  An r-strategist is generally a_______________.  ____________life span  Produces ____________offspring 4.1 Population Dynamics  The rate strategy, or r-strategy, is an adaptation for living in an environment where fluctuation in biotic or abiotic factors occur. Chapter 4

Population Ecology  A k-strategist is generally a ________organism.  _______________life span  Produces____________ offspring 4.1 Population Dynamics  The carrying-capacity strategy, or k- strategy, is an adaptation for living in stable environments. Chapter 4

Human Population Growth  The study of human population size, density, distribution, movement, and birth and death rates is demography. 4.2 Human Population Population Ecology Chapter 4

Technological Advances  For thousands of years, environmental conditions kept the size of the human population at a relatively constant number below the environment’s carrying capacity. Population Ecology  Humans have learned to alter the environment in ways that appear to have changed its carrying capacity. 4.2 Human Population Chapter 4

Human Population Growth Rate  Although the human population is still growing, the rate of its growth has slowed. Population Ecology 4.2 Human Population Chapter 4

Trends in Human Population Growth  Population trends can be altered by events such as disease and war. Population Ecology 4.2 Human Population Chapter 4  Human population growth is not the same in all countries.

 Zero population growth (ZPG) occurs when the birthrate equals the death rate. Population Ecology Zero Population Growth  The age structure eventually should be more balanced with numbers at pre-reproductive, reproductive, and post-reproductive ages being approximately equal. 4.2 Human Population Chapter 4

Age Structure Population Ecology  A population’s age structure is the number of males and females in each of three age groups: pre-reproductive stage, reproductive stage, and post- reproductive stage. 4.2 Human Population Chapter 4

Human Carrying Capacity Population Ecology  Scientists are concerned about the human population reaching or exceeding the carrying capacity.  An important factor is the amount of resources from the biosphere that are used by each person. 4.2 Human Population Chapter 4

Check it? 1. Name 2 types of limiting factors for a population. 2. Of the following factors with the potential to limit growth of a human population, which one is most density-independent? –Mass drowning caused by hurricane flood –Freezing deaths due to a shortage of housing

Check it? 3. Which of the following is NOT a condition for a population to reach exponential growth? –presence of unlimited resources –absence of predation and disease –movement of individuals out of a population