Natural ecosystems and human activities

Question 1

Define ecosystem

Answer 1

The community of living plants, animals and micro-organism species in an area (biotic community) and how they interact with each other and with non-living (abiotic) elements of the environment, such as rocks, soil and water

Question 2

Define habitat

Answer 2

The location within an ecosystem that meets the living needs of particular plants or animal species- the shelter, food, water they need to survive

Question 3

Define ecological niche

Answer 3

The unique way in which it is adapted to living in the habitat, for example the type of food it eats

Question 4

Define food chain

Answer 4

The succession of organisms that eat another organism and are, in turn, eaten themselves

Question 5

Define food web

Answer 5

Shows how individual food chains within a habitat are linked together and interdependent

Question 6

Levels of food chains

Answer 6

Producers
Primary consumers
Secondary consumers
Apex consumers

Decomposers on every level as organisms all die

Question 7

Producers role

Answer 7

Plants or algae that manufacture their own food from nutrients in soil or water such as nitrates through photosynthesis

Question 8

Explain photosynthesis

Answer 8

CO2+ Water+ Sunlight –> Oxygen+ Glucose

Sunlight is absorbed by chlorophyll, and the heat energy is used to convert CO2, water, and minerals absorbed from the soil into oxygen and glucose (sugar),

Question 9

Process of aerobic respiration

Answer 9

Used to release energy from the food

Glucose+ oxygen –> Energy+ water+ CO2

Occurs in the mitochondria cell where enzymes control the release of energy

Question 10

Herbivores + Carnivores difference

Answer 10

Herbivores are the primary consumers

Carnivores (and omnivores) are the secondary consumers as they eat animals not only the plants

Question 11

Decomposers role

Answer 11

Fungi and bacteria break down complex substances into simpler inorganic chemicals that return to the abiotic environment as recycled mineral nutrients for producers to use again.

Question 12

Explain the energy flow

Answer 12

Producers store the suns energy in chemical compounds such as proteins and carbohydrates

Herbivores gain this store of energy by consuming the plants

This continues till the final trophic level, where remaining chemical stores of energy are recycled through decomposition and return to the abiotic environment

10% RULE

Question 13

Explain the carbon cycle

Answer 13

1. Respiration in these plants releases some of this fixed carbon back as carbon dioxide
   Combustion releases CO2
   Animal respiration also releases CO2 into the atmosphere

2.
CO2 in the atmosphere is converted into compounds such as carbohydrates in ‘producer plants’ during photosynthesis

3.
Decomposers convert some carbon compounds from the dead plants, and animals back into CO2 during respiration

Question 14

Interactions between biotic components

Answer 14

1. Competition-
   Shortage of resources that are required by many
2. Predation
   One organism preying on another as a source of food
3. Pollination
   Pollen containing male gametes/ sperms are transported to the female reproductive organs of seed plants
4. Mutualism
   Involves both individuals benefiting from the activity of another symbiotic relationship
   e.g. Lichen (Algae (provides food) & Fungi (provides moisture))

Question 15

Define genes + gene pools

Answer 15

Genes, found in the nucleus of cells provide instructions for what the plant or animal will look like, how it will survive, and how it will interact with its environment

A gene pool is the set of all the genes or genetic information of a specific species

Question 16

Define deforestation

Answer 16

The clear-curring or permanent destruction of forests and woodlands

Question 17

Causes of deforestation

Answer 17

1. For farming
2. For wood- construction, paper, furniture
3. For extracting valuable rocks and minerals
4. Urban sprawl
5. Construction of new transport links

Question 18

Impacts of deforestation

Answer 18

1. Habitat loss and depletion of biodiversity and gene pool diversity
2. Global warming and climate change- when trees burn
3. Soil erosion & Desertification-
   Removing the protective cover of trees causes erosion as the soil is more vulnerable to wind and water- soil nutrients are lost& Overgrazing

Question 19

Functions of forests

Answer 19

1. Carbon sinks, stores, and offset programs- they absorb CO2 during photosynthesis
2. Maintaining the water cycle through transpiration
3. Prevention of soil erosion- tree roots create a stable binder & foliage preventing the erosive impact of heavy rain
4. Biodiversity and genetic gene pools
5. Food and industrial raw materials- indigenous ppl especially
6. Ecotourism

Question 20

Define ecotourism

Answer 20

Responsible travel to natural areas that conserves the environment, sustains the wellbeing of the local people, and involves interpretation and education

Question 21

Sampling methods

Answer 21

1. Quadrats-
   a square frame subdivided into smaller squares
   determines the number, variety, and spread of living things
2. Line transect-
   laying a measuring tape/rope with marked points across the habitat
   recording all species touching the line or absence/presence of the species at intervals is recorded
3. Pooters-
   small jars with two tubes- one used to suck insect
4. Pitfall traps-
   insects reach the lip of the buried container and get trapped in

Question 22

Factors that would affect the validity of the estimates

Answer 22

1. The sample size- More methods are needed throughout the day
2. Sampling frequency- Throughout the year
3. Human error- always trying to use the least effort method

Question 23

Ways to conserve biodiversity

Answer 23

1. Sustainable harvesting- collection of resources in a manner that ensures the long term viability of the ecosystem by leaving the resources in place from which it will continually regenerate.
2. Sustainable forestry- as trees are felled they are replaced with seedlings that in time replace the harvested trees
3. Designated protected areas- protected by the law, national park/wildlife reserve to conserve biodiversity, protect landscapes and enhance economic& social conditions of communities
4. Extractive reserves- land owned by the government allocated to the indigenous locals
5. Seed banks- in case natural reserves are destroyed/ reduced

Question 24

Define pyramid of numbers

Answer 24

A diagram that shows the number of individual organisms in different trophic levels of a food chain

Question 25

Define pyramid of energy

Answer 25

A diagram that shows the transfer of declining stores of energy between organisms at different trophic levels

Question 26

Define sustainable development

Answer 26

The development of technology and the environment to meet increasing human needs and living standards without impacting negatively on the ecosystems

Question 27

Define Population

Answer 27

all the organisms of one species living in a defined area at the same time.

Question 28

Define Niche

Answer 28

the role of a species within the ecosystem.

Question 29

Define community

Answer 29

: a group of populations of different species that live together in an area and interact with each other

Question 30

Uses of energy

Answer 30

Energy is:
Lost during transfer as heat to the environment;
Used for cellular respiration;
Used for growth;
Movement 
Excretion 
Proteinsynthesis