Agenda 9/4 FRQ Warm Up Pop Ecology Lecture Green Pepper ‘Lab’ Turn in: Chp 53 notes, Video notes Homework -R vs. K video and notes -Population growth video and notes (maybe) finish green pepper lab

Population Ecology

Populations A group of organisms that are the same species

Population Dispersal Clumped Distribution Uniform Random Advantages? Disadvantages? Uniform Random

Geographical Range Natural range expansions occur Cattle egrets came to the US in the late 1800s Their geographical range and distribution has expanded What could contribute to this?

The Spread of the Africanized Honey Bee When did they first arrive in the Americas? How long did it take for them to expand their range into the US? How can you explain their success in expanding their territory? Take this opportunity to let students practice interpreting graphics. First arrived? Researchers brought the African bees to Brazil in the 1950s in an attempt to improve the productivity of Brazilian bees. How long to reach US? 40 years! A large wild population quickly developed and spread through South America, Central America and Mexico. In the 1990's, the Africanized honey bee was identified in Texas and has since spread though the southwest US. Why successful? Many correct answers including: African bees produce more offspring, defend their nests much more fiercely and in greater numbers and are more likely to abandon the nest when threatened by predators or adverse environmental conditions.

Most species have small geographic range

Abiotic and Biotic Factors Affect Geographic Ranges

What factors influence geographical range?

Survivorship Curves 25 1000 100 Human (type I) Hydra (type II) Oyster (type III) 10 1 50 Percent of maximum life span 75 Survival per thousand The curves are used to summarize the typical reproduction, population size, and survival of a particular species Each curve represents a typical ‘survivorship’ of a species These curves also reveal other details about the life of the species

Survivorship curves 25 1000 100 Human (type I) Hydra (type II) Oyster (type III) 10 1 50 Percent of maximum life span 75 Survival per thousand What do these graphs indicate regarding species survival rate & strategy? I. High death rate in post-reproductive years II. Constant mortality rate throughout life span Type I curve is flat at the start, reflecting low death rates during early and middle life, then drops steeply as death rates increase among older age groups. Humans and many other large mammals that produce few offspring but provide them with good care often exhibit this kind of curve. Type II curves are intermediate, with a constant death rate over the organism’s life span. This kind of survivorship occurs in Belding’s ground squirrels and some other rodents, various invertebrates, some lizards, and some annual plants. Type III curve drops sharply at the start, reflecting very high death rates for the young, but then flattens out as death rates decline for those few individuals that have survived to a certain critical age. This type of curve is usually associated with organisms that produce very large numbers of offspring but provide little or no care, such as long–lived plants, many fishes, and marine invertebrates. An oyster, for example, may release millions of eggs, but most offspring die as larvae from predation or other causes. Those few that survive long enough to attach to a suitable substrate and begin growing a hard shell will probably survive for a relatively long time. III. Very high early mortality but the few survivors then live long (stay reproductive)

Population Reproductive Strategies There are two patterns of reproductive strategies seen in organisms 1. R-selected (opportunistic) Ex: Bacteria 2. K-selected (equilibrial) Ex: Humans

Population Reproductive Strategies r-selected (opportunistic) Short maturation & lifespan Many (small) offspring; usually 1 (early) reproduction; No parental care High death rate K-selected (equilibrial) Long maturation & lifespan Few (large) offspring; usually several (late) reproductions Extensive parental care Low death rate Emphasize that these r-selected and opportunistic are synonyms as are K- selected and equilibrial. It’s the synonyms that will give students fits when they are reading and interpreting test questions!

Green Pepper Lab!