Population dynamics Exponential Growth Exponential growth of a

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Population dynamics

Population dynamics

Exponential Growth Exponential growth of a population of organisms occurs when the # of

Exponential Growth Exponential growth of a population of organisms occurs when the # of organisms rises at an everincreasing rate.

Population Growth of Houseflies Population size 1 million 500, 000 100 One year

Population Growth of Houseflies Population size 1 million 500, 000 100 One year

What are some things that prevent populations from growing exponentially?

What are some things that prevent populations from growing exponentially?

Carrying Capacity The number of organisms that a particular environment can support over an

Carrying Capacity The number of organisms that a particular environment can support over an indefinite period of time. – Births will exceed deaths until carrying capacity is reached

Number of Yeast Cells Carrying capacity Time (hours)

Number of Yeast Cells Carrying capacity Time (hours)

4 population growth graphs

4 population growth graphs

Exponential vs. Logistic growth

Exponential vs. Logistic growth

Limiting factors 1. 2. 3. Density-dependent Density-independent Predation

Limiting factors 1. 2. 3. Density-dependent Density-independent Predation

Limiting factors 1. 2. 3. Density-dependent – Have an increasing effect as population increases

Limiting factors 1. 2. 3. Density-dependent – Have an increasing effect as population increases – Ex. Disease, parasites, competition, crowding & stress Density-independent – Affects all populations, regardless of their density – Usually abiotic factors: ex. storms, floods, temp, fire Predation – keeps population size within limits (density-dependent)

Practice Classify each of the following as either densitydependent or density-independent. 1. Intense heat

Practice Classify each of the following as either densitydependent or density-independent. 1. Intense heat wave 2. Large population of caterpillars infected with wasp larvae parasites 3. Overpopulation of an organism 4. Clear cutting of a forest to build a shopping center.

Exotics Species living in an area to which they are not native Can be

Exotics Species living in an area to which they are not native Can be introduced accidentally or on purpose Ex. Sika from Asia brought to South TX

n How do you think introducing Sika into the population would affect the native

n How do you think introducing Sika into the population would affect the native population of deer?

Swamp Rats in California

Swamp Rats in California

https: //www. mysanantonio. com/bayarea/article/nutri a-should-we-eat-invasive-species-swamp-rats 12726054. php#photo-15020981

https: //www. mysanantonio. com/bayarea/article/nutri a-should-we-eat-invasive-species-swamp-rats 12726054. php#photo-15020981