Chapter 4 – Population Ecology Ms. Ferris Flushing High School

Ch. 4 Objectives I can describe the characteristics of populations (4-1) I can understand the concepts of carrying capacity and limiting factors (4-1) I can describe the ways in which populations are distributed (4-1) I can explain how technology has affect human population growth (4-2)

Ch. 4-1 Population Dynamics What is a population? A group of organisms of the same species in the same area at the same time. There are certain characteristics that all populations have Population density Spatial distribution Growth rate

Population Density Population density is the number of organisms per area. Example: There are 256 daisies in a sqkm.

Spatial Distribution Spatial distribution is the pattern of spacing of a population within an area. There are 3 pattern types: Uniform = even/equal spacing Clumped = groups/clusters/clumps Random = no noticeable pattern

Growth Rate Growth rate is how fast a population grows. Emigration = moving AWAY from an area Immigration = moving INTO an area There are two types of growth Exponential = slow at first then rapidly increases Logistic = an “S” shaped growth pattern

Limiting Factors There are two types of factors that limit populations. Density-independent factors = usually abiotic (nonliving) and includes weather events – drought, flooding, extreme heat or cold, tornadoes, and hurricanes. Density-dependent factors = usually biotic (living) – predation, disease, parasites, and competition. Isle Royale, U.P. Michigan These limiting factors define how large of a population that a single area can support. The maximum number of individuals of a species that an environment can support is called the carrying capacity.

Reproductive Patterns Reproductive patterns are determined by a species reproductive cycle – age in which it can start to reproduce and life span. Species have developed these reproductive strategies in order to effectively pass on their DNA/genes. There are two types of strategists: Rate strategists Carrying-Capacity strategists

R-Strategists Small organisms – fruit flies, mice, and locust. Short life-spans Produces many offspring Little to no energy is used to take care of or raise offspring Usually controlled by density-independent factors like weather conditions

K-Strategists Larger organisms – elephants, humans, and whales. Long life-spans Few offspring Spends a lot of time and energy caring for offspring Usually controlled by density-dependent factors like predators, competition, and disease.

Ch. 4-2 Human Population The study of human population size, distribution, movement, birth and death rates is called demography. What did you notice about those graphs in regards to human population over time? Why do you think the human population has increased so much in the last 200 years? Technological and medical advances Look at pg. 102 Figure 4.13