Ecosystems

Question 1

What is an ecosystem?

Answer 1

An area where living (biotic) organisms and non-living (abiotic) environmental factors interact, forming a relatively self-sustaining system driven by energy flow and nutrient cycles

Question 2

What are abiotic factors?

Answer 2

Non-living conditions in a habitat

Question 3

What are biotic factors?

Answer 3

The living components of an ecosystem

Question 4

What is a habitat?

Answer 4

The place where an organism lives within an ecosystem

Question 5

What is a niche?

Answer 5

• The role of an organism within an ecosystem
• Where an organism lives, its position within a food web, how it lives (what specific influence it and how it affects the ecosystem)
• Only one species can occupy a specific niche

Question 6

What is a population?

Answer 6

A group of individuals of the same species occupying a given space at a give time

Question 7

What is a community?

Answer 7

A group of interacting populations in a habitat/ecosystem

Question 8

What are the three main types of biotic factors?

Answer 8

• Autotrophs (e.g. producers)
• Heterotrophs (e.g. consumers)
• Detritivores (e.g. decomposers)

Question 9

Draw the diagram for types of nutrition.

Answer 9

Answer on revision card.

Question 10

What is autotrophic nutrition?

Answer 10

A process of obtaining carbon from Carbon dioxide

Question 11

What is photoautotrophic nutrition?

Answer 11

A process of obtaining carbon from Carbon dioxide using energy from light

Question 12

What is chemoautotrophic nutrition?

Answer 12

• A process of obtaining carbon from Carbon dioxide using energy from chemical reactions
• This starts food chains where there is no sunlight e.g. hydrothermal vents deep in the ocean

Question 13

What is heterotrophic nutrition?

Answer 13

A process of obtaining carbon from breakdown of organic compounds

Question 14

What is holozoic nutrition?

Answer 14

A process of obtaining carbon by ingestion and internal digestion of organic compounds

Question 15

What is saprotrophic nutrition?

Answer 15

Process of heterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter

Question 16

What are autotrophs?

Answer 16

Organisms that produce their own food

Question 17

What are two examples of autotrophs?

Answer 17

• Plants and algae, for example, use sunlight to produce food from carbon dioxide and water (a process called photosynthesis).
• Other organisms like bacteria produce food using chemicals instead of sunlight as the energy source (chemosynthesis).

Question 18

What are heterotrophs?

Answer 18

Organisms that consume other organisms

Question 19

What are three examples of heterotrophs?

Answer 19

• Herbivores like deer and cows feed on plants
• Carnivores like lions and tigers feed on other animals
• Omnivores like humans and pigs feed on both animals and plants

Question 20

What are detritivores?

Answer 20

• Organisms that shed detritus, ingest it and digest it internally (holozoic nutrition)
• The precede decomposers in the process of decomposition
• They are heterotrophs that consume dead or decaying organisms
• By breaking down dead and decaying material into inorganic nutrients, detritivores contribute to nutrient cycling in an ecosystem

Question 21

What are some examples of detritivores?

Answer 21

Examples of detritivores are earthworms, maggots, sea cucumbers, and crabs

Question 22

What are some other examples of biotic factors that affect an ecosystem?

Answer 22

• Predator-prey relationship => part of a food chain. Numbers of each affect the other cyclically
• Intraspecific competition => competition between members of the same species
• Interspecific competition => between members of different species
• Intraspecific cooperation => cooperation between members of the same species e.g. social insects (bees and ants)
• Interspecific cooperation => cooperation between members of different species (mutualism or symbiosis e.g. coral and algae/or commensalism where one species gains and the other is neutral)
• Providing a habitat
• Disease => e.g. pathogens and parasites

Question 23

What is meant by an ecosystem being dynamic?

Answer 23

• Dynamic is a word to describe the change in distribution and abundance of species in an ecosystem over time
• Ecosystems often experience disruptions, or changes
• These changes can happen in either living (biotic) or nonliving (abiotic) parts of an ecosystem

Question 24

What are the 3 types of change in an ecosystem?

Answer 24

1. Cyclic change => repeat in a rhythm e.g. tides, changes in day length/season
2. Directional change => gradual change in one direction that lasts longer than lifetime of organisms e.g. silt in estuary, erosion of coastline, succession
3. Erratic/unpredictable change e.g. hurricane, lightening, tsunami, forest fires

Question 25

What are the 3 general categoreis of abiotic factors?

Answer 25

- Climatic factors e.g. light intensity, temperature range, precipitation, wave action, wind - Topographic factors e.g. altitude, aspect (which way you're facing), gradient, shape of land - Edaphic factors e.g. featires of the soil, riverbed

Question 26

What are some examples of abiotic factors?

Answer 26

- Temperature - pH - Depth of water - Flow rate - Oxygen concentraion - Turbidity - Dissolved minerals - Light intensity - Type of soil substrate

Question 27

How does **temperature** affect abundance and distribution in an ecosystem? And how can it be measured?

Answer 27

- Temperature range determines the species that can survive - Can be measured using a thermometer or digital probe

Question 28

How does **pH** affect abundance and distribution in an ecosystem? And how can it be measured?

Answer 28

- Many species cannot survive in acidic conditions - Can be measured using a universal indicator paper or digital probe

Question 29

How does **depth of water** affect abundance and distribution in an ecosystem? And how can it be measured?

Answer 29

- This determines the size of the fish that can survive - Can be measured using a meter rule

Question 30

How does **flow rate** affect abundance and distribution in an ecosystem? And how can it be measured?

Answer 30

- Some species cannot survive fast rates and are swept downstream - Can be measured by timing how long a floating object takes to travel a set distance

Question 31

How does **oxygen concentration** affect abundance and distribution in an ecosystem? And how can it be measured?

Answer 31

- Few species can survive low concentrations - Can be used by a using a digital probe

Question 32

How does **turbidity** affect abundance and distribution in an ecosystem? And how can it be measured?

Answer 32

- Makes vision difficult for predatory fish - Can be measured using a colorimeter

Question 33

How does **dissolved minerals** affect abundance and distribution in an ecosystem? And how can it be measured?

Answer 33

- Provide ions for various metabolic processes - Can be measured using a conductivity meter

Question 34

How does **light intensity** affect abundance and distribution in an ecosystem? And how can it be measured?

Answer 34

- Influences the rate of photosynthesis of submerged plants - Can be measured using a lux meter

Question 35

How does **type of soil substrate** affect abundance and distribution in an ecosystem? And how can it be measured?

Answer 35

- Some species burrow into mud and sand, others have flattened bodies to survive under stones - Can be measured using a visual description e.g. rock, sand and mud