The factors together:

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1 Biotic Interactions 8.11A DESCRIBE PRODUCER/CONSUMER, PREDATOR/PREY AND PARASITE/HOST RELATIONSHIPS AS THEY OCCUR IN FOOD WEBS WITHIN MARINE, FRESHWATER AND TERRESTRIAL ECOSYSTEMS

2 Biotic These are the living organisms in any given ecosystem Animals vertebrate or invertebrates Plants flowering and non-flowering Fungi mushrooms, molds Micro-organisms bacteria, protists (see ex.)

3 Abiotic biotic and abiotic factors interact in ecosystems. organisms are dependent on the abiotic and biotic factors in their environment. Abiotic factor examples: Sun, heat, light, temperature, rocks, soil, wind, precipitation, air, water, clouds

4 The factors together:

5 Biotic Interactions In Ecosystems There are several types of interactions (also known as feeding relationships ) among organisms in ecosystems. Other interactions are caused by competition for food and resources

6 Producer/consumer Relationships

7 Roles within Ecosystems Producer/autotroph organism that makes its own food, such as a plant or photosynthetic alga. Recall that in order to make their own food, autotrophs use the sun s energy to convert water and carbon dioxide in to food, a sugar - glucose. This is the process of photosynthesis,

8 Roles within Ecosystems Consumer/heterotroph - an organism that feeds on other organisms There are different tiers or levels of consumers Include organisms that feed only on autotrophs, organisms that feed solely on other heterotrophs, and organisms that feed on both auto and heterotrophs.

9 Roles within Ecosystems Primary consumer (first level consumer) animals that get their energy from eating plants These are always herbivores, but can also be omnivores

10 Roles within Ecosystems Secondary consumer (second level consumers) animals that get their energy from eating other animals Always carnivores, but also some omnivores

11 Roles within Ecosystems Tertiary consumer (top level consumers) animals that get their energy from eating other animals Top carnivore (may also be omnivore like bears) Note there can be higher levels than tertiary, but these are few and far between due to energy transfer that occurs within an ecosystem

12 Roles within Ecosystems Decomposer simple organism, such as bacteria or fungus, that breaks down dead organisms and waste, returning important nutrients to the environment

13 How do these various roles come about? Biotic factors include food chains and webs where some organisms might share food sources setting up competition Many organisms are adapted to survive in ecosystems by resource partitioning they feed at different times of day or at different levels in the same tree Carrying capacity the number of animals that can obtain food, shelter, and water from the environment in a given area; the ability of an environment to support its animal population

14 Competition Competition - occurs when organisms try to make use of the same limited resources Competition occurs between: Members of the same species Among species with similar niches They are competing for abiotic or biotic resources How do these examples to the right compete?

15 How does a niche come about? A niche is - an organism s particular role, or how it fits into an ecosystem A niche is created when species compete Many organisms are adapted to overcome competition by resource partitioning: They feed at different times of day Or at different levels of the same tree

16 Words to Know Resource partitioning- helps competing species share a resource and develop a niche for themselves in an ecosystem. For example: Species of birds will feed at different times of day Or at different levels of the same tree

17 Warbler example:

18 Carrying Capacity: Carrying capacity is the largest number of individuals of a population that a given environment can support. Living within the limits of an ecosystem depends on three factors: the amount of resources available in the ecosystem, the size of the population, and the amount of resources each individual is consuming (using).

19 Carrying Capacity: An example of a situation in which the carrying capacity of an environment is exceeded is the example of deer in North America. After the widespread elimination of wolves the natural predator of North American deer the deer reproduced until their need for food plant species exceeded the environment s ability to regenerate their food plants. In many areas, this resulted in large numbers of deer starving until the deer population was severely reduced.

20 Predator/Prey Relationships

21 Predation Predation - An interaction in which one organism hunts and kills another for food Hunter predator Gets eaten - prey

22 Predator Adaptations Predators have adaptations that help them catch and kill their prey. Cheetahs can run very fast to catch prey Jellyfish have poisonous tentacles to paralyze prey Owls have big eyes to see at night

23 Prey Adaptations Prey have adaptations to help them avoid predators Camouflage Protective coverings Warning coloring Mimicry False coloring

24 Effects on Predation on Population Size Predation can have a major effect on population size If predators are very effective, the result is a decrease in the prey population In turn, a decrease in the prey population will result in a decrease in the predator population

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26 Parasite/Host Relationships

27 Symbiosis A close relationship between two different species that benefits at least one of the species Benefits of Symbiosis: Food Transportation Cleaning Protection/Shelter Reproduction There are three types of symbiotic relationships:

28 Mutualism Both species benefit Remora fish clean sharks of external parasites and in return receive free rides and food. Giraffes and oxpecker birds

29 Commensalism One species benefits and the other is unaffected Ex. Clown fish are protected from predators by sea anemones poisonous tentacles. The relationship does not affect the sea anemone negatively or positively. Barnacles and whales

30 Parasitism One gains considerably at the expense of the other Host the organism that the parasite lives on or in it will be harmed Parasite the organism that benefits Reef Symbiosis