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ECOSYSTEMS An ECOSYSTEM is made of all the living & nonliving things that interact in a particular area Ecosystems can be large or small.

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Presentation on theme: "ECOSYSTEMS An ECOSYSTEM is made of all the living & nonliving things that interact in a particular area Ecosystems can be large or small."— Presentation transcript:

1 ECOSYSTEMS An ECOSYSTEM is made of all the living & nonliving things that interact in a particular area Ecosystems can be large or small

2 FACTORS THAT AFFECT THE GROWTH OF A POPULATION When conditions are good, a population will generally increase. But a population does not keep growing forever. Eventually some factor in its environment causes the population to stop growing.

3 LIMITING FACTORS LIMITING FACTORS: Biotic and abiotic factors that prevents a population from increasing. –Food –Water –Living space –Temperature –Predation –Competition

4 Environmental abiotic and biotic factors can also be termed "Limiting Factors." They are limiting in that they tend to have the least affect on those organisms which have the best tolerance, or adaptation to the factor. At different times of the year, some abiotic factors take on more importance than others. These factors help to keep a population at or below carrying capacity. Limiting Factors

5 LIMITING FACTORS FOOD & WATER -When food is scarce, the population numbers will decrease from starvation or low birth numbers. -When food if plentiful, numbers increase because of low death rates and high birth rates.

6 SPACE -If the plant or animal does not have enough room to reproduce and grow, the numbers will decrease. -When space is plentiful, the pop- ulation will increase. LIMITING FACTORS

7 CLIMATE - Conditions such as drought and temperature changes can limit the population growth. -Too cold, too hot, too wet, too dry all affect population growth. Early frost can kill many insects and plants. -Favorable weather conditions such as seasonable temps, rainfall etc, can increase populations.

8 Predation Predation is the type of feeding relationship in which one animal captures and eats another animal for its food. Prey – is eaten Predator – captures and eats prey.

9 LIMITING FACTORS Predator/Prey Relationship Predation has a huge effect on the size and growth of a population. -If there are more predators or they are more efficient at hunting techniques, then the prey species goes down.

10 Predator/Prey Continued - Predators affect prey species numbers and prey species affect predators numbers. As predator numbers decrease, the prey species numbers will increase due to less predators in the area.

11 PREDATOR/PREY RELATIONSHIP Predators directly affect the population of their prey and the prey directly affect the population of the predator. How is this possible?


13 What is the carrying capacity of this ecosystem for the rabbits? Fox?

14 Name the carrying capacity of this environment for the wolves and the moose.


16 Remember, when the prey species goes up, the predator goes up SHORTLY THEREAFTER. When the prey species goes down, the predators go down, SHORTLY THEREAFTER.

17 LIMITING FACTORS COMPETITION -When two or more individuals or populations try to use the same resources. Can occur within populations or between populations

18 Limiting Factors -When competition for resources is high (many organisms fighting for the same one), populations will decrease. -When competition for resources is low, populations will increase.

19 Competition Competition – occurs whenever more than one individual or populations tries to make use of the same limited resources.

20 LIMITING FACTORS DISEASE -When disease (fungal, parasitic, bacterial, viral) is introduced to a population, population numbers are affected. Only the strongest individuals overcome the disease and survive.-

21 Limiting Factors Introduced Species Humans sometimes move organisms to a location where they do not belong. Sometimes they die, but often they prosper. If the organism has no predators, then its population will grow. An example of this occurring is the kudzu plant. It was transplanted to America and nothing eats it here. So, it grows out of control. This causes native plants to loose the space, sunlight and water supply they need to survive.

22 Brown Tree Snake Shortly after World War II, and before 1952, the brown Treesnake was accidentally transported from its native range in the South Pacific to Guam, probably as a stowaway in ship cargo. As a result of abundant prey to eat on Guam and the absence of natural predators and other population controls, brown Treesnake populations grew. Snakes caused the loss of most of the native forest vertebrate species; thousands of power outages affecting private, commercial, and military activities; widespread loss of domestic birds and pets. Most songbirds of Guam have gone extinct.

23 Brown Tree SnakeCane Toad

24 Cane Toad Cane toads, introduced into Australia to control beetles that were destroying sugarcane crops, are still spreading across Australia. They failed to control the cane beetles, and became a major pest themselves. Cane toads can harm native wildlife by eating small animals and poisoning larger predators that try to eat them. Household pets are also at risk from poisoning. So far, there is no known way to control cane toads across large areas, but scientists are searching for a biological control agent that is specific to the toads.

25 Name the limiting factors in the pictures below:

26 CARRYING CAPACITY The maximum number of organisms an ecosystem can successfully support.

27 Symbiosis Any close relationship between species. Individuals in the relationship are either: 1. Helped 2. Unaffected 3. Harmed

28 Mutualism A relationship in which both species benefit Cleaner fish Lichens: algae + fungus Zebra & oxpecker

29 Commensalism A relationship in which one species benefits and the other is neither helped nor harmed Barnacles on whale Shark & remora

30 Parasitism A relationship in which one organisms benefits and the other is harmed. The individual that benefits is called the parasite, the one harmed is called the host. Tick Mistletoe

31 Coevolution The evolution of two species totally dependent on each other. Coevolution is an extreme example of mutualism. Yucca flowers are a certain shape so only that tiny moth can pollinate them. The moths lay their eggs in the yucca flowers and the larvae (caterpillars) live in the developing ovary and eat yucca seeds. Yucca moths and yucca plants

32 Acacias are small, trees that have large, hollow thorns. The acacia ants live in the thorns. On the tips of its leaflets, the plant makes a substance used by the ants as food. The ants defend the tree from herbivores by attacking/stinging any animal that even accidentally brushes up against the plant. The ants also prune off seedlings of any other plants that sprout under “their” tree Acacia ants and acacia trees

33 The pollinator gets a reward such as nectar for pollinating the plant. Insects (beetles) on the plant found this protein/sugar mix and used it as food. Insects became dependent on this food source and started carrying pollen from plant to plant. Beetle-pollination must have been more efficient than wind for some species, so there was natural selection for plants that attracted insects. Coevolution is often seen in a number of species of flowering plants that coevolved with specific pollinators (insects, bats, etc).

34 Examples of Symbiosis


36 Botfly Dustmite Tapeworm

37 Limiting Factors ORQ Proficient 1. 900 2. Food, water, space, disease, competition, predators, intro. New species, climate, natural disaster. You must DECSRIBE how the factors affected the population. NOT list. 3.The adding of a new species would decrease the squirrel population because they would use all of the resources. 4. Yes the Earth has a carrying capacity because the Earth has a limited number of resources

38 Limiting Factors ORQ App. Or Novice 1. Got the number wrong makes it a 1 or 2. 2.If they just listed – food, water, disease, climate, intro new species, disaster, space. If they just listed with no discussion or only listed one or incorrect. 1 or a 2. 3.They did not say it went down. If they said it went up or blank, it is a 1. 4.If they said the Earth had not capacity – 1 If they did not explain why - 2

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