When one tugs at a single thing in nature, they find it attached to the rest of the world

a. Species Diversity

• 
  What kinds of behaviors do some species do to enhance their chances of survival?
  
• 
  Some behaviors are harmful, some are beneficial.
  

1. Commensalism

2. Mutualism

3. Parasitism

4. Predation (predator/prey)

5. Competition

Which Symbiosis is it?

1. 
   Oxpecker and zebras: Oxpeckers are a type of small bird that land on zebras and eat ticks and other parasites that live on the zebra’s skin. The oxpeckers get food and the zebras get pest control.
   

Organism 2:  helped harmed not harmed/not helped

Symbiotic Relationship: _____________________________

2. 
   Tapeworm and animals: Tapeworms are segmented flatworms that attach themselves to the insides of the intestines of animals such as cows, pigs, and humans. Tapeworms get food by eating the host's (animal) partly digested food, depriving the host (animal) of nutrients.
   

Organism 2:  helped harmed not harmed/not helped

Symbiotic Relationship: _____________________________

3. 
   Spider crab and algae: Spider crabs live in shallow areas of the ocean floor, and greenish-brown algae lives on the crabs' backs, making the crabs blend in with their environment, and unnoticeable to predators. The algae get a good place to live, and the crab gets camouflage.
   

Organism 2:  helped harmed not harmed/not helped

Symbiotic Relationship: _____________________________

4. 
   Remora and the shark: Remora fish are small fish that make their niche by picking up the scraps that sharks leave behind while feeding. The shark makes no attempt to prey on the remora fish.
   

Organism 2:  helped harmed not harmed/not helped

Symbiotic Relationship: _____________________________

5. 
   Bee and the flower: Bees fly from flower to flower-gathering nectar, which they make into food. When they land in a flower, the bees get some pollen on their hairy bodies, and when they land in the next flower, some of the pollen from the first one rubs off, pollinating the plant.
   

Organism 2:  helped harmed not harmed/not helped

Symbiotic Relationship: _____________________________

6. 
   Bacteria and the human colon: Bacteria live in the colon of humans and are able to feed off the indigestible food that the human body cannot break down (cellulose of plants). In the process of breaking down the food, the bacteria also make much-needed vitamins that the human body in turn can use to keep healthy.
   

Organism 2:  helped harmed not harmed/not helped

Symbiotic Relationship: _____________________________

7. 
   Dog and the tick: Ticks live on dogs and feed off the dog’s blood. They may also infect the dog with a parasite that can cause the dog to become quite sick. Dogs also are sometimes found to be very tired because a large volume of their blood has been drained.
   

Organism 2:  helped harmed not harmed/not helped

Symbiotic Relationship: _____________________________


II. Limiting Factors and Population Growth

A. Read the truly riveting passage below about population growth. If, while reading, you are asked to do something, then do it.

DGT = I don’t get this. I had to re-read this to try and understand it.

!! = I am surprised to find this out

?? = I have a question about this (write your question in the margin)

b) The Mantled Howler Monkey (found in Mexico and South America) is currently considered an endangered species. What does this mean about its birth and death rates?

While populations would probably like to continue to grow in size, a population of organisms cannot grow forever—its growth will be limited, or stopped, at some point, and the death rate will be greater than the birth rate. A population’s growth is limited by two general factors: density-independent factors and density-dependent factors. Why are these factors named in such a complicated way? Well, actually, these names aren’t as complicated as they seem; in fact, they can even help you remember what each of the terms means.

Now that you know about population density, we can talk about the difference between the two types of limiting factors. If a factor that stops a population’s growth is influenced by the population’s density, then it is called a density-dependent limiting factor. If the population’s density does not influence whether or not the factor stops the population’s growth, then it is called a density-independent limiting factor.

b) List a possible density-dependent factor that would limit the skunk population’s growth.

a) What is the rabbit population’s carrying capacity? ________

1. a turtle walking (super slow) 2. a student running late to class (fast!)

a) Fill in the differences chart below:

The amount of resources is not the only limiting factor that depends on a population’s density. Diseases and parasites can limit a population’s growth once the population reaches a certain number of organisms. The more organisms there are, the faster a disease can spread or a parasite can be transferred to another organism because there are more available hosts that are near each other. Competition for resources—either between the same species or two different species—will also decrease a population’s size. Resources are limited in any habitat, and, when populations reach a certain size, there will not be enough to go around. When two organisms in the same habitat are trying to use the same resource, they are competing for that resource. Whichever organism has the better adaptations to obtain that resource will be able to reproduce more often, and their population will grow. The organism that is not successful at competing for the resource will not reproduce as often, and their population will decrease.