Reproductive Strategies & Population Growth https://www.youtube.com/watch?v=kxuijR_KdPg

Reproduction Strategies What are some reproductive strategies that animals are using?

Reproductive Strategies Survivorship curve: helps to describe the reproductive strategies of a species Is a diagram that shows the number of organisms that survive over time, starting from birth There are 3 basic patterns: Type I Type II Type III

Reproductive Strategies Type I Typical for humans and large mammals Few death of infant offspring and most will survive to old age Parents care for their young

Reproductive Strategies Type II Typical of birds, small mammals, and some reptiles At all points of life these animals have equal chances of living or dying, either from disease or predation

Reproductive Strategies Type III Typical for invertebrates, fish, amphibians and plants Large number of offspring or produce many eggs or seeds Many of the offspring will die from predation, only a few will survive to adulthood

Conclusion Each type of curve represents a different reproductive strategy. Some organisms have few offspring and most will survive. Other organisms may lay thousands od eggs, only a few will survive to maturity.

Population Growth Patterns Change in a population’s size are determined by 4 factors: Immigration Movements of individuals into an area Birth Increase the number of individuals Emigration Movement of individuals out of an area Deaths Decrease the size of a population

Population Growth Patterns The size of a population is always changing. If there are plenty of resources (Food, Water, etc…) a population grows. If there are few resources, the population decreases.

Population growth Population growth is based on available resources. There are 2 types of population growths:

Ecological Factors that limit population growth Density- dependent limiting factors Caused by population density The number of individuals living in one area Competition Predation Parasitism & disease

Ecological Factors that limit population growth Density-independent limiting factors Affect the size of the population no matter how many individuals live in the area Unusual weather Natural disasters Human activity