Food Webs/Chains
What is the source of energy for food chains/food webs?
Sun
What organisms are at the bottom of an energy pyramid?
Producer
What is primary succession?
The type of succession that begins with bare rock is likely due to a natural disaster such as a volcanic eruption
What is secondary succession?
it begins on land that already has life on it. The land gets disturbed, but soil remains.
In this type of interaction, the disappearance of bees could disrupt plant reproduction and food availability for many organisms. What type of ecological relationship is being demonstrated between bees and plants?
A. Commensalism
B. Mutualism
C. Predation
D. Parasitism
Mutualism
The bees need the plants for food, and the plants need the bees to reproduce.
Which organism is likely to be at the beginning of a food chain for a pond?
(Hint: which organisms always come first in a food chain?)
A) Algae
B) Frog
C) Snail
D) Turtle
Algae
Describe the amount of energy that is passed between trophic levels.
10% of energy is passed from one trophic level to the next. This is the Law of Ten.
Which of the following natural disasters causes primary succession? (Hint: Consider what primary succession begins with)
A) Earthquake that levels a city
B) Flood that deposits nutrient-rich soil
C) Hurricane that knocks down trees in a forest
D) Volcanic eruption that forms new land from lava
Volcanic eruption that forms new land from lava
Which of the following natural events is most likely to lead to secondary succession?
(Hint: Secondary succession begins in areas where soil is already present.)
A) Glacial retreat exposing bare rock
B) Wildfire that burns a forest but leaves the soil intact
C) Lava flow forming new land
B) Wildfire that burns a forest but leaves the soil intact
In the trophic levels, how much of the energy in each level gets lost as heat or is undigested by an organism?
90%
What do the arrows indicate in a food web?
Where the energy is being transferred
In a forest, a large population of deer begins to suffer from a contagious disease that spreads more quickly as the population increases.
Which type of limiting factor is this?
A) Density-independent
B) Abiotic Factors
C) Density-dependent
C) Density-dependent
After a volcanic eruption, lava covers the land. What is the order that plants grow to repopulate the area? (Hint: Consider what type of succession may happen after a volcano)
A) Grasses → Lichens → Shrubs → Trees
B) Lichens → Grasses → Shrubs → Trees
C) Shrubs → Grasses → Trees → Lichens
D) Trees → Shrubs → Lichens → Grasses
Lichens → Grasses → Shrubs → Trees
A sudden wildfire sweeps through a grassland ecosystem, killing plants and animals regardless of how many lived there.
What kind of limiting factor caused this event?
A) Density-dependent
B) Predator-prey
C) Density-independent
D) Biotic factor
Density-independent, limiting factors that are abiotic or non-living factor
One species benefits while the other is unaffected—like a barnacle hitching a ride on a whale without harming it.
What ecological relationship is being demonstrated?
A. Mutualism
B. Commensalism
C. Parasitism
Commensalism
The elk population in Yellowstone grew rapidly, but then started to decline as grass became scarce from overgrazing.
What is the most likely reason for the decline?
A) The elk migrated to find more space
B) The carrying capacity was exceeded
C) A disease reduced the population
D) Park visitors hunted too many elk
B) The carrying capacity was exceeded
In a food pyramid, which organisms have the most energy available?
Primary Producer
Provide an example of a pioneer species in primary succession.
Lichen and mosses
What condition allows secondary succession to occur more quickly than primary succession?
A) Absence of plant and animal species
B) Presence of established soil
C) Reduced sunlight and increased rainfall
D) Volcanic activity creating new land
Presence of established soil
If there is 1000 Kcal available in the producers in trophic level 1, how much energy is available in the herbivores in trophic level 3?
10 Kcal
Why can't the top level contain a large number of organisms?
(Hint: Consider why there is only one apex predator)
The amount of energy available at the top of the pyramid is not sufficient to sustain many individuals.
Consumers that eat plants and animals are called ____.
Omnivore
In the following example, which plant represents the climax community?
Lichens → Grasses → Shrubs → Trees
A field was abandoned and left untouched for several years after a fire, allowing the natural process of succession to occur. Which order of succession is most likely to occur in the meadow? (Hint: Consider what type of succession begins with a "fire")
A) Bare rock → Mosses → Shrubs → Hardwood trees
B) Grasses → Shrubs → Softwood trees → Hardwood trees
C) Lichens → Ferns → Cacti → Rainforest trees
D) Mosses → Algae → Succulents → Vines
Grasses → shrubs → softwood trees → hardwood trees
An owl eats a rat that lived in an ecosystem where there was 2,800 kcals of energy in the insect population that the rat consumed. How many kcals would transfer to the trophic level the owl is in?
Hint: Consider the food chain
Grass→ Insects → Rat → Owl
28 Kcal
Starting point 2,800 kcal insects
Rat (secondary consumer) receives 10% of 2,800 kcal:
→ 2,800/ 10 = 280 kcal
Owl (tertiary consumer) receives 10% of the energy from the rat:
→ 280/10 = 28 kcal