Relationships & Interactions Among Organisms Chapter 1, Section 3: Environmental Science

Interactions with the Environment Limiting Factors- a resource needed that becomes scarce Keeps populations from growing out of control Examples: limited amounts of food, water, space Something that LIMITS a population size

Limiting Factors

Interactions with the Environment Carrying Capacity – the largest population a given environment can support over a long period of time A population may temporarily exceed its carrying capacity, but a limiting factor will return it to the carrying capacity.

Interactions Among Organisms Competition Predator/ Prey Symbiosis Coevolution

Competition 2 or more animals or populations try to use the same limited resource (food, water, space, sunlight, shelter) Can occur between members of the same species Can occur between different species Occurs between plants too!

What are these trees in this forest competing for?

Predator and Prey Predator: any organism that exists by killing and eating other organisms. Prey: an animal hunted or seized for food, especially by a Carnivorous animal.

Predator/Prey Predators have adaptations to help them capture prey. Prey have adaptations to help them escape or hide from predators.

What are the adaptations? Paradoxophyla palmata Grey Wolf

What are the adaptations? A school of fish Prairie Dogs Tiger Shark

What are the adaptations? The Atlantic Green Turtle Elk living in a herd

Coevolution * Co-evolution occurs when, in adapting to their environments, two or more organisms evolve together. To "make the best of" where they live, organisms make use of other organisms by eating them, living on or in them, and/or building a "partnership" with them.

Symbiosis A close long-term relationship between 2 or more species. 3 types: Mutualism Commensalism Parasitism

Mutualism Both organisms benefit ++ Lichens: a fungus and algae that cannot exist separately Pollination The sea anemone and clownfish offer protection for each other.

Mutualism Oxpecker on large herbivores The birds eat the ticks off of the animals.

Commensalism +0 ? One is helped, one is unaffected. But some do say it is mutualism Remora fish and sharks

Commensalism Non-poisonous look alike Viceroy Poisonous Monarch Mimicry A hermit crab with an unknown rider on its back. A hermit crab with a sea anemone on its back.

Parasitism +- One organism benefits and one is harmed. Parasite – gets the benefits Host – is harmed, the parasite usually lives on the host A flea worms

Parasitism Most parasites do not kill the host; they only harm it and make it sick. Why do you think they don’t kill the host? Head Lice – YIKES!! The heads of a tape worm and a hook worm; both can live in intestines. – YUCK!