Friday, October 24, 2014

population dynamics

1. Using an example, describe why a population could not increase forever.

A population can't increase forever because it will take other population's resources and it will run out of them. Consequently, the planet can't let that happen so it will find a way to balance the populations. (wiping out a part of the population). For example, we humans have taken a lot of resources that don't belong to us so the earth created Ebola to balance things out.

2. What are 2 factors that determine whether a population increases or decrease.

One factor that determines if a predator population increases is that if the prey population increases the predator population increases because they have more food. A factor that determines if a population decreases is the planet. If there is very big population and it is taking a lot of resources, the planet will find a way to decrease the population so that it doesn't take to many resources.

3. Give a reason why the population of earth has continued to increase in the past 100 years?

Firstly, our scientists have found a lot of cures for sicknesses that killed us in the past. This makes us live longer. Secondly, we humans have used up one fourth more of the planet's resources that it has for us. If we keep taking all the resources the planet will have to wipe us out to protect the other populations.

Tuesday, October 21, 2014

symbiosis

Simbiosis

Symbiosis: is the relationship of two different species that live together and how they affect each other.

There are three types of symbiosis: mutualism, commensalism, and parasitism.

Mutualism: when the relationship of the species benefits both species. For example, the relationship of a dog and a human because the dog gets taken care of, fed and kept healthy and the human gets company, exercise and a protection.


Commensalism: when the relationship of the species only benefits one of the and nothing happens to the other species . For example, the relationship of sharks and small fish called remoras because they stick to a shark to travel and when the shark kills something the remoras eat scraps. It benefits the remoras but nothing happens to the shark.

Parasitism: when the relationship benefits one of the species and harms the other. For example, the relationship of a lettuce and a worm. It benefits the worm because it gets food easily but the lettuce gets bitten so it starts to rot and dies.

This connects to what we have been doing in class because in class we have seen how species affect one another and population. This connects to population because when simbiosis happens species help each other survive or one species harms another and that affects the population in a ecosystem.

Friday, October 3, 2014

discussion questions

Why do we as scientists build food webs?

We build food webs to understand nature, how animals survive and to understand if one of the animals goes extinct what would happen to the rest of the world. Also, to see which animal we can let hunt and which animals we should protect. We need to understand how ecosystems work and connect to other ecosystems.

Give an example of how one change might affect many other parts of an ecosystem. 

The frog is eaten by owls and hawks. The frog eats insects. The owl also eats snakes. The hawk also eats mice. If the frogs go extinct, The population of the insects increase and the population of the mice and snakes decrease because the hawks and owls have to eat more of the mice and snakes.

Give an example of how one change in la quebrada might affect the rest of the ecosystem.

If the trees of the quebrada are turned into buildings the population of birds will decrease because they don't have where to live and so they will die or migrate to another place. That will affect the worms because they won't be eaten and they will grow in the dirt below the building. Also, the water will be polluted by the materials needed to make the buildings and the fish will die.