Topic 1 - Ecosystems

Question 1

What is the difference between a food chain and a food web?

Answer 1

Food chains show the path of energy from one living thing to another, starting with a plant. Energy from the sun once trapped by plants is passed along the chain.

Food webs are when all the food chains in an ecosystem are joined together. Multiple consumers feed on the same thing, so food chains link, forming food webs

Question 2

What are the different types of organisms found in freshwater ponds?

Answer 2

Ponds are freshwater ecosystems found throughout the UK that host a variety of freshwater species. Freshwater pond ecosystems consist of different organisms that product and transfer energy through the system.

Producers:
Algae and microscopic plants

Decomposers:
detritus (decaying matter), worms and maggots

Consumers:
Kingfishers are birds which eat perch (predatory fish)
Midge larva (freshwater worms) eat algae v Perch’s are predatory fish which eat stickleback fish / Great diving beetles eat water boatmen (insects)
Mayfly’s eat microscopic plants
Herons each stickleback fish

Question 3

What are the elements of an ecosystem?

Answer 3

Elements of an ecosystem:
Producer = convert energy from the Sun through photosynthesis and take nutrients from soil using roots
Primary consumer = herbivores (plant eating animals)
Secondary consumer = carnivores (feed on herbivores)
Tertiary consumer = eat carnivores as well as herbivores
Decomposer = breakdown organic material. Returns nutrients to soil
Eutrophication = water body (pond) becomes overly enriched with nutrients, leading to the plentiful growth of plant life.

Question 4

What does abiotic mean and give examples?

Answer 4

Abiotic - non living components of ecosystems
Rocks help in the formation of soils. Weathering releases nutrients stored in the rock.
Soils store water & contain nutrients that plants use.
Sunshine and rain are needed for photosynthesis

Question 5

What does biotic mean and give examples?

Answer 5

Biotic - living components of ecosystems
Plants include trees, flowers, mosses and algae
Animals found in a woodland include species of insects, birds and mammals
Micro-organisms like fungi and bacteria are decomposers. They break down dead plants/animals releasing nutrients

Question 6

What is an ecosystem?

Answer 6

Ecosystems = interdependent communities made up of plants,
animals and their surrounding physical environment, including soil, rainwater and sunlight.

Question 7

What factors can affect the sustainability of ecosystems?

Answer 7

Natural: Droughts, floods, volcanic eruptions, climate change.
Human: Deforestation, desertification, climate change.

Question 8

How does an ecosystem stay sustainable?

Answer 8

Ecosystems can take hundreds if not thousands of years to develop. If an ecosystem is to be sustainable it needs to be in balance. If there is a change to one of the components it may have knock-on effects for the rest of the ecosystem.

Question 9

Where does the rest of the energy go?

Answer 9

Changes to the temperature. Some energy will be used to form heat energy, especially in ecosystems which become cooler at night time or during certain seasons.
Faeces. Some of the biomass eaten is excreted as waste (faeces). This is passed to decomposers as it is broken down.
Bones and roots. Many parts of plants arent eaten by animals, like the roots and carnivores do not eat all of their prey, like the bones.
Life processes. Some energy is used for life processes such as respiration or hunters like hawks use a lot of kinetic energy chasing their prey.

Question 10

How much energy is transferred along the food chain?

Answer 10

Energy is transferred along food chains from one level to the next.
However, only 10% of the energy is passed on to the next level.
The rest of the energy passes out of the food chain.

Question 11

What is biomass?

Answer 11

Biomass - the total quantity or weight of organisms in a given area or volume.

Question 12

What are the characteristics of tundras?

Answer 12

Tundra (or cold desert) - found at the Arctic Circle, where the Sun’s rays have little strength. Temperatures below freezing for most of the year. Tough, short grasses can survive.

Question 13

What are the characteristics of deciduous forest?

Answer 13

Deciduousforest - Found in western Europe, the east coasts of Asia, North America and New Zealand. Grow in many places at higher latitudes. Sun’s rays are weaker due

Question 14

What are the characteristics of the Mediterranean?

Answer 14

Mediterranean - 30° and 40° north and south of the equator, but only on the west coasts of continents. Drought-resistant small trees and evergreen shrubs grow.

Question 15

What are the characteristics of hot deserts?

Answer 15

Hot deserts - Found close to the Tropics of Cancer and Capricorn.
The air that rises over the Equator heads towards the poles after shedding its moisture as rain. The Sun’s rays are still highly concentrated at this low latitude.

Question 16

What are the characteristics of coniferous forests?

Answer 16

Coniferous forests - Found at 60° north. Winter temperatures are extremely cold due to lack of insolation. Due to the Earth’s tilt, there is no sunlight for some months. These trees have needle leaves that reduce moisture and heat loss during the cold, dark winter months.

Question 17

What are some of the different types of large-scale ecosystems?

Answer 17

tropical rainforests
coniferous forests
deciduous forests
hot deserts
mediterranean
tundra

Question 18

What is the characteristics of tropical rainforests?

Answer 18

Tropical rainforests - These lie along the Equator in Asia, Africa and South America. The Sun’s rays are concentrated at this latitude, heating moist air which rises and leads to heavy rainfall. Little seasonal variation, creating conditions for evergreen rainforest.

Question 19

What are examples of human changes to ecosystems?

Answer 19

Ponds may be drained to use for farming through irrigation
Hedgerows are removed to increase the size of fields.
Woods are cut down for farming practices.
Agricultural fertilisers can lead to eutrophication: nitrates increase the growth of algae which will deplete oxygen and fish may die
Reintroduction of grey wolf into the Yellowstone National Park has caused a range of impacts. Elk population halved in 8 years, increased populations of grizzly bears due to increase in food for scavengers

Question 20

What are examples of natural changes to ecosystems?

Answer 20

Krakatoa volcanic eruption in Indonesia in 1883 destroyed all their rainforests
Extreme weather events like droughts and floods can be devastating to ponds and lakes
Wildfires directly impact on upland ecosystem services through damage caused to the vegetation, peat and soils, which results in loss of valuable habitat and associated wildlife alongside carbon release.

Question 21

How does the global atmospheric circulation affect global ecosystems?

Answer 21

At the equator, the ground is intensely heated by the Sun.
This causes the air to rise because the air is less dense
(lighter). This creates a low pressure zone. As the air rises, it cools and condenses to form clouds and then precipitates.
This is where tropical rainforests
are found which are rich in vegetation. The air separates and starts to move towards the tropic of Cancer (north) and the tropic of Capricorn (south).
When it reaches about 23.5N/S, the air cools and sinks towards the ground. This is because the air is more dense (heavier). This creates a high pressure zone. This is where hot deserts are found which are sparse in vegetation

Question 22

How does the altitude affect the temperature of ecosystems?

Answer 22

Altitude refers to the height of a particular location above sea level.
The higher the altitude, the colder the climate becomes. This is because the air at higher altitudes is less dense and contains less moisture, which makes it more difficult to retain heat. As a result, high-altitude regions tend to have cooler temperatures, with lower humidity levels.. Mountains and high-altitude regions tend to have more precipitation because of the orographic effect. When air is forced to rise over a mountain range, it cools and moisture condenses, leading to rainfall or snowfall. This can result in localized climate patterns, with wetter conditions on one side of a . mountain range and drier conditions on the other.

Question 23

How do the lines of latitude affect the temperature of ecosystems?

Answer 23

In the lower latitudes at the Equator, temperatures are highest. In the higher latitudes, such as the polar regions, temperatures are lowest. Temperatures drop the further an area is from the equator due to the curvature of the earth. In areas around the equator, sunlight has a smaller area of atmosphere to pass through, and the sun’s rays are concentrated in a smaller area. In areas closer to the poles, sunlight has a larger area of atmosphere to pass through and the sun is at a lower angle in the sky. More energy is lost so temperatures are cooler.