Homework answers / question archive / Question 1 1 / 1 pts Fossils of past life forms can be found as far back as 5

Question 1 1 / 1 pts Fossils of past life forms can be found as far back as 5

Biology

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Question 1

1 / 1 pts

Fossils of past life forms can be found as far back as 5.7 billion years ago.

  

True

   

False

 

 

Question 2

1 / 1 pts

All life must have a way to transmit information between generations.

  

True

   

False

 

 

Question 3

1 / 1 pts

What is a mass extinction?

  

When most of the members of one species dies off rapidly.

   

When there is a sudden "burst" of new species in the fossil record.

   

When a great many species dies off simultaneously (in geologic terms).

   

It refers to the normal loss of species and gain of new species over 3.5 billion years.

 

 

Question 4

1 / 1 pts

What may have caused past mass extinctions? 

  

New favorable habitats arising due to continental drift.

   

Sea level rise and fall.

   

The changing oxygen concentration in the atmosphere.

   

Asteroid impacts and volcanoes.

 

 

IncorrectQuestion 5

0 / 1 pts

All of the following are true regarding natural selection EXCEPT

  

Mutations are necessary for variation. 

   

Individual organisms evolve to fit their environment. 

   

Undesirable characteristics are selected against. 

   

Those most fit for their environment leave the most offspring. 

 

 

Question 6

1 / 1 pts

Where are oxygen minimum zones generally found?

  

Below areas of high surface productivity.

   

Center of gyres.

   

Where western margin currents generate warm water eddies.

   

Wavy shorelines.

 

 

Question 7

1 / 1 pts

How do marine fish balance salinity levels in their bodies?

  

They absorb salt through their gills to make up for the salt lost to the environment. 

   

They "pump" salt out of their body through their gills and urine. 

  

They produce large volumes of salt-free urine in order to concentrate the salt remaining in their tissues. 

   

They drink as much water as possible to dilute the salt in their tissues. 

 

 

IncorrectQuestion 8

0 / 1 pts

Why is the biological pump important?

  

It cycles nitrogen and phosphorus through the ocean for use by plants and algae.

   

It removes carbon, which helps to regulate the climate.

   

It cycles carbon from the sea floor up to the surface for use by producers.

   

It ensures that nutrients from below the compensation depth are upwelled to the productive surface waters.

 

Episode 20

 

Question 9

1 / 1 pts

How does primary productivity occur deep in the ocean at hydrothermal vents? 

Select all correct answers.

  

Downwelling of photosynthetic organism and surface nutrients.

   

Photosynthesis from the dark red light radiating from the vents. 

   

Super-heated water drives the synthesis of carbohydrates from calcium carbonates and carboinc acids.

   

Chemosynthesis - converting hydrogen sulfide, carbon dioxide, and oxygen into carbohydrates.  

 

 

Question 10

1 / 1 pts

Which organism below generally has two flagella, is capable of bioluminescence, and is sometimes responsible for harmful algal blooms (HABs)?

  

Diatoms

   

Cyanobacteria

   

Coccolithophores

   

Dinoflagellates

 

 

Question 11

1 / 1 pts

What happens when fertilizers wash into coastal waters?

  

Sea grasses tend to outnumber native algae species, and the coastal food web becomes favorable to grazing invertebrates. 

   

The spike in coastal nutrients kills the normal algae and waters become clear and "sterile."

  

There is an initial algae bloom, which causes high productivity and unusually high fish growth rates. 

   

First there is an algae bloom, but then there is a die-off of algae, which causes anoxic (low oxygen) conditions. 

 

Episode 20

 

Question 12

1 / 1 pts

What four requirements do primary producers need to photosynthesize?

  

Water, carbon monoxide, sulfur, heat.

   

Water, carbon dioxide, light and nutrients.

   

Carbon dioxide, heat, nutrients, phosphorus.

   

Those found near hydrothermal vents.

 

 

Question 13

1 / 1 pts

What can hinder photosynthetic productivity in the open ocean?

  

Waters depleted of non-conservative nutrients

   

Upwelling of deep water

   

Overabundance of nitrate

   

Over abundance of carbon dioxide

 

 

Question 14

1 / 1 pts

What is the major difference between algae and plants?

  

Algae live in the ocean and plants do not.

   

Algae do not photosynthesize like plants

   

Algae lack the conductive tissue found in plants.

   

Algae do not use chlorophyll.

 

 

Question 15

1 / 1 pts

Why is productivity low in tropical waters away form land?

  

Weak surface currents

   

The strong thermocline

   

The intense sunlight

   

The warm water