lec 20

Question 1

Action we are performing that lead to habitat loss

Answer 1

1. Habitat destruction
2. Over exploitation
3. Invasive species
4. Pollution
5. Climate change

Question 2

Approximately _% of the worlds forests are _____

Answer 2

15

untouched by human hands

Question 3

_% are impacted and most importantly _% of the land once containing forest __________

Answer 3

57
28
have lost so many trees that they cannot be called forests

Question 4

Since the 1960s ___________ has expanded significantly in canada

Answer 4

the construction of dams

Question 5

In many causes dams are considered _________ but this is

Answer 5

a renewable green source of power

not always the case

Question 6

Many dams seriously __________
As well as _____
and _______

Answer 6

alter the flow regime of a river
water quality
aquatic/near shore habitat

Question 7

____________ can be a major cause of extinction

Answer 7

introduced species

Question 8

Species are introduced into new environments for many reasons such as

Answer 8

Intentionally for agricultural purposes (honey bees)
Intentially for sport (trout/pheasents)
Unintentionally transoported via human transport (zebra mussel/rusty crayfish)
Intentionally for the pet or gardent industries (dandelions)

Question 9

Introduced species that survive and become invasive ___________

Answer 9

spread and outcompete native species for space and resources

Question 10

Economic costs of invasive species in Canada have been estimated at

Answer 10

13 billion per year

Question 11

Sea lampretys are a

Answer 11

primitive jawless fish native to the Atlantic Ocean

Question 12

Lampreys entered the Great Lakes through the

Answer 12

ship canals and locks built to bypass obastcles in naigra falls

Question 13

How lampreys kill kish

Answer 13

their mouth is an oral disc that is like a suction cup to attach to side of fish

• teeth on the tongue rasp through the skin
• an anticoagulant in saliva maintains blood flow in lampray feeds

Question 14

Lake trout populations crashed as

Answer 14

lamprety population grew

Question 15

Following the crash of the top predators

Answer 15

populations of invasive prey species like rainbow smelt and alewlife increased rapidly
these invasive species out competed native species
extinction so the deepwater sculpin and cisco

Question 16

zebra mussels are native to _____
They were transported to the great lakes via ____
Sea water is pumped into and out of ______
An estimated ______

Answer 16

the Caspian sea region of Asia
ballast water from a transoceanic vessel
ballast tanks which serve to stabilize ships

Question 17

zebra mussels first discoved in
Since then they have spread rapidly
The mussels attach onto any hard substrate

Answer 17

the great lakes in the mid 1980s
to all of the Great Lakes and connected waterways in many US staes, as well as Ontario, Quebec and Manitoba
including other organisms and are easily transported

Question 18

A female zebra mussel can produce
whcich can establish dense population up to
May cover bottom waters or beaches with
Mussels reduces species of algae and microscopic aquatic animals

Answer 18

on million eggs per year
7000,000 per m^2
dead mussel shells up to 30 cm deep
that are imortant for the food web with their impressive filering capacity

Question 19

Carp
Introduced _______
they escaped _____
They are voracious eaters ______

Answer 19

to the US from China in the 1970s to clean fish farm tanks and as a food source
and over the last 30 years have steadily moved north on the Mississippi River system
grow very large, have devastating effect on native fish populations

Question 20

A less obvious cause of human damage
This is much more controversial and hard to quantify
Historically Co2 levels

Answer 20

is the alteration of biogeochemical cycles
compared with other human caused diversity losses
have been significantly higher than today, however it is not the level that matters per se, it is the rate of change and the fact that todays ecosystems have evolved to live within current CO2 levels

Question 21

Temperature is similar in that recent trends

Answer 21

can not be conclusively linked to human activity but are undoubtedly rising

Question 22

From a geoloical time point of view

Answer 22

it is uncommon to have glaciers that persist throughout the year; so perhaps it makes sense that the Earth is warming

Question 23

It is not a matter of absolute temperature

Answer 23

but a matter of the rate of change

Question 24

Ice caps have

Answer 24

been in retreat for 20,000 years

Is the current retreat part of an overall trend or due to climate change

Question 25

Something that kills lamprey

Answer 25

lampricide