Unit 7 Ecology Test (Bio)

Question 1

Define Autotrophs.

Answer 1

(All producers), self-feeders

Question 2

Define Heterotrophs.

Answer 2

other-feeders (organisms that feed on other organisms)

Question 3

Name the different trophic levels and their names.

Answer 3

I (Autotroph, Producer), II (Heterotroph, Primary Consumer), III (Heterotroph, Secondary Consumer), III (Heterotroph, Tertiary Consumer), IIII (Heterotroph, Quaternary Consumer)

Question 4

Define Producers.

Answer 4

Organisms that convert/transfer light energy from the sun into chemical energy in chemical bonds.

Question 5

Define Consumers.

Answer 5

Organisms that obtain energy by eating other organisms / Primary (1°) consumers are herbivores or omnivores / Secondary (2°) consumers and beyond are carnivores.

Question 6

Define Predator.

Answer 6

An animal that preys on others.

Question 7

Define Biotic Factors.

Answer 7

All living things or previously living things in an ecosystem that shapes its environment. (debris/detritus that was made of cells)

Question 8

Define Abiotic Factors.

Answer 8

Components of an ecosystem that were never alive (never made of cells) shape an ecosystem.
Ex. Temperature, humidity, water, light, minerals

Question 9

What are the causes and dangers of biological magnification?

Answer 9

The cause of biological magnification is when toxins, such as DDT or mercury, contaminate environments and are thus consumed by plants. The toxins remain in those plants and are then eaten by many other animals along the food chain and carry the toxins with them. The higher the species is on the pyramid, the more toxins they would get as they consume more plants or animals and build up more toxins inside them. These toxins can become deadly, namely, when humans eat animals higher up in the food chain, they can die from being poisoned by the toxins. For instance, many people have died due to eating dolphin meats that were highly contaminated with mercury. The danger is that predators higher in the food web have a higher concentration of toxins, including humans, which has the potential to kill many.

Question 10

What is the stability of ecosystems based on the complexity of food webs and the importance of biodiversity on an ecosystem’s stability?

Answer 10

The complexity of food webs and biodiversity can determine the stability of an ecosystem. A higher level of complexity and biodiversity provides more opportunities for other organisms to fill in roles that others leave behind.

Question 11

Describe the Predator/Prey Relation.

Answer 11

This relation is where one species, named a predator, relies on hunting another organism (the prey) for food.

Question 12

Define Mutualism.

Answer 12

Both organisms benefit from interacting with each other.

Question 13

Define Commensalism.

Answer 13

One organism benefits and the other is neither harmed nor helped when they interact with each other.

Question 14

Define Parasitism.

Answer 14

One organism benefits and the other is harmed when they interact with each other.

Question 15

Define Symbiosis.

Answer 15

Two organisms interact and live closely together; 3 types

Question 16

Define competition.

Answer 16

Organisms fighting over the same resource at the same time.

Question 17

Define the 1% and 10% rules.

Answer 17

The 1% rule applies to the energy transfer between the sun and the produces which consumes the energy (calories) that the sun provides. In this case, only 1% of the energy that comes from the sun is absorbed by plants. The 10% rule applies the energy transfer amount in a similar fashion, though this time the transfer amount is 10% of the original amount of energy and it applies to all energy transfers aside from the sun to producers.

Question 18

What defines a calorie? What is the difference between a calorie and a Calorie?

Answer 18

1 calorie = the amount of energy it takes to lift the temperature of 1g of H2O by 1°C
1 Calorie = 1Kcal = 1000 calories

Question 19

Explain the differences between Exponential Growth and Logistic Growth.

Answer 19

While Exponential Growth is a rapid rate of reproduction and only happens when there is plenty of food and resources and is also improbable in reality (also a J-curve on graphs), Logistic Growth occurs in many populations as it usually stops when the carrying capacity is reached and is represented on a graph as an S-curve.

Question 20

What factors affect carrying capacity?

Answer 20

Resource availability (food, water) and space.

Question 21

What are the two categories of elements that limit population growth?

Answer 21

Density-dependant: more deaths in larger populations / ex. predation, resource limits, disease
Density-independent: deaths happen regardless of population size / ex. weather, natural disasters

Question 22

How does predation and competition limit population sizes?

Answer 22

In predation, many predators can hunt down and kill any prey that could be growing in number and competition can limit the amount of resources one species can get, thus reducing the population when the size grows too much for everyone to live.

Question 23

How does carbon cycle?

Answer 23

The carbon organisms use starts normally as carbon dioxide in the atmosphere or in the ocean, which is then taken in by plants through the air or water and turned into mass through photosynthesis. The plants are eaten by animals, taking the carbon with them. The carbon can either be respirated back into the ocean or air or decomposed into the ground and turn into fossil fuels, eroded into the ocean, or blasted back into the air from volcanic activity.

Question 24

How does water cycle?

Answer 24

Water from bodies of water or from leaves is evaporated or transpired into the atmosphere where they cool down and condense into clouds. The water droplets are then large and heavy enough to fall back to the ground as rain to be collected back in the bodies of water or absorbed by plants (runoff).

Question 25

Define Nitrogen Fixation?

Answer 25

Bacteria convert nitrogen gas into nitrates that other types of cells can assimilate (take in) and use (N2 → NO3)

Question 26

Define Denitrification.

Answer 26

Bacteria convert nitrates back into nitrogen gas. (NO3 → N2)

Question 27

How does nitrogen cycle?

Answer 27

Nitrogen from the air goes into the soil where bacteria turn it into nitrates and nitrites for plants to consume. Animals then consume the plants along with the nitrogen which is then either decomposed back into the soil to be reused again for denitrification by certain bacteria be placed back into the atmosphere.

Question 28

How does phosphorus cycle?

Answer 28

Phosphorus is absorbed by plants from the soil or ocean sediment when released phosphorus gets into oceans. The phosphorus is then passed along in the food chain to other animals and then back into the ground from poop.

Question 29

In what forms are the nutrients previously mentioned used by plants and animals?

Answer 29

Carbon - They makeup food, help plants make food, and provide energy in the form of fossil fuels. (gas, solid)
Nitrogen - All organisms need it to make amino acids. (solid)
Phosphorus - It forms part of important life-sustaining molecules such as DNA and RNA. (solid)
Water - Is needed for all living things to survive. (liquid)

Question 30

Describe the following environments in terms of temperature and precipitation. (Tundra, Desert, Tropical Rainforest, Coniferous Forest/Taiga, Grasslands, Temperate Deciduous Forest)

Answer 30

Tundra - highly cold and little precipitation
Desert - highest temperatures and little precipitation
Tropical Rainforest - moderately high temperatures (2nd highest) and the highest amount of rainfall
Coniferous Forest/Taiga - moderately low temperatures (2nd lowest) and moderate rainfall (3rd highest)
Grasslands - moderate temperatures (3rd highest) and moderately low rain (3rd lowest)
Temperate Deciduous Forest - similar temperatures to grasslands and high amounts of rainfall (2nd highest)