2) Organisms in the ecosystem must respond appropriately to winter and summer conditions in order to survive. However, a
drastic change in an ecosystem often requires different responses by organisms so they can survive.
Scientists have observed that many polar bears can't seem to find enough food to satisfy their high energy requirements.
Vanishing sea ice in their home environment makes the predators' hunt for seals incredibly difficult potentially pushing the
species closer to extinction
Which of the following would best describe the change to the environment described in the above scenario?
A)
climate change
ghlight
Time
maining
04:37
Tools
B)
poaching
Succession
D)
seasonal variation
3)
If the producers in a food web were removed, which of the following changes would most likely occur?

an individual’s sex (i.e., whether they are a male or female) is determined by the sex chromosomes. most people have two sex chromosomes, one that is inherited from their mother and one that is inherited from their father. typically, females have two x chromosomes (xx) and males have one x chromosome and one y chromosome (xy). conditions caused by changes (“mutations”) in genes located on the x chromosome are considered x-linked.

x-linked recessive inheritance

most x-linked conditions are recessive. this means that in a person with two x chromosomes (most females), both copies of a gene (i.e., one on each x chromosome) must have a change or mutation whereas in a person with one x chromosome (most males), only one copy of a gene must have a mutation. a female with a mutation in one copy of a gene on the x chromosome is said to be a “carrier” for an x-linked condition. a male with a mutation in a gene on the x chromosome is typically affected with the condition. because females have two copies of the x chromosome and males have only one x chromosome, x-linked recessive diseases are more common among males than females. however, x-linked recessive diseases can occur in both males and females.

for x-linked recessive disorders, an unaffected carrier mother who has a mutation in a gene on the x chromosome can transmit either the x chromosome with this mutation or a “normal” x chromosome to her children. if the father is unaffected, none of her daughters will be affected and all of her daughters will be unaffected—since they will inherit at least one normal x chromosome from their father. however, each daughter will have a 50% chance of being an unaffected carrier like her mother and a 50% chance of both x chromosomes being normal.