Ecosystem

Question 1

habitat definition

Answer 1

the place where an organism lives

Question 2

population definition

Answer 2

all the organisms of one species living in a habitat

Question 3

community definition

Answer 3

the population of different species in a specific area at a give time

Question 4

ecosystem definition

Answer 4

the interaction of a community of living organisms (biotic factors) interacting with non-living (abiotic) part of the environment

Question 5

Competition of a shared resource can happen between:

Answer 5

• 2 individuals of the same species: intraspecific competition
• 2 individuals of different species: interspecific competition

Question 6

4 things plants compete for

Answer 6

• light
• space
• mineral ions
• water

Question 7

4 things animals compete for

Answer 7

• food
• water
• territory
• mates

Question 8

biotic factor definition

Answer 8

any living factors that affect an ecosystem

Question 9

name 4 biotic factors

Answer 9

• competition for resources or habitat
• new pathogens
• availability of food
• one species outcompeting another so the numbers are no longer sufficient to breed

Question 10

abiotic factor defnition

Answer 10

non-living parts of the environment that can affect organisms

Question 11

name 7 abiotic factors

Answer 11

• light intensity
• Temperature
• Moisture level
• Mineral content and pH of soil
• CO2 concentration
• oxygen levels for aquatic animals
• wind intensity and direction

Question 12

explain how temperature is a abiotic factor

Answer 12

• animals spend less energy staying warm –> more energy to grow

Question 13

explain how light intensity is a abiotic factor

Answer 13

• increate rate of photosynthesis enzyme reactions

Question 14

what is a trophic level

Answer 14

different feeding stages within a food chain

Question 15

what does Level 1 consist of

Answer 15

Producers: Plant + Algae
- make their own food –> Photosynthesis
- obtain energy from sunlight

Question 16

what does Level 2 consist of

Answer 16

Herbivores: Primary consumers
- only eat plants/ algae

Question 17

what does Level 3 consist of

Answer 17

Carnivores: secondary consumers
- eat herbivores

Question 18

what does Level 4l consist of

Answer 18

Carnivores: Tertiary consumers
- carnivores that have no predators –> they are apex predators

Question 19

biomass definition

Answer 19

the total mass of dried organic material that makes up a living/ recently decease organism

Question 20

what does pyramids of biomass represent

Answer 20

they represent the relative amount of biomass in each level of a food chain

Question 21

what happens to the biomass as your move higher up the trophic levels and why

Answer 21

biomass decreases
- energy is lost between tropic levels
- less organisms are in each higher trophic level

Question 22

approximately what is the percentage of biomass is transferred to the level above it

Answer 22

10%

Question 23

Losses of biomass are due to what 3 reasons:

Answer 23

• excretion - water and
  urea
  are excreted in urine
• respiration - carbon dioxide and water are waste products of
  aerobic respiration
  , which is carried out by organisms to keep warm and provide energy for the organism
• egestion - undigested food passes through the organism and is egested as solid
  faeces

Question 24

bioaccumulation definition

Answer 24

build up of toxins / harmful chemicals through consumers

Question 25

what are the 2 main ways of bioaccumalation

Answer 25

- **chemicals enter** living organism **faster** than organism can break it down and use it - chemicals come into living organism and the organism **unable to break it down or excrete it**

Question 26

what are the 4 factors of interdependence

Answer 26

- **food security** - **pollination** / seed dispersal - **shelter** + **warmth** - **decomposition** - releases nutrients for future organisms

Question 27

when do stable communities occur

Answer 27

when **all the species and environmental factors are in balance** --> so population sizes remain fairly constant e.g. rainforests, ancient oak woodlands

Question 28

what are the 4 steps of predator- prey relationships: starting with increase of prey

Answer 28

Step 1: **prey population increases** --> population size of **predator will increase after lag period** Step 2: **increase in predators**--? **decrease in the prey** Step 3: causes **decrease*** in **no. prey available --> no. predators fall (lack of food) Step 4: **decrease in predators** --> no. **prey increases** , cycle continues

Question 29

what are the 3 types of adaptation

Answer 29

- structural - behavioural - functional

Question 30

what are structural changes

Answer 30

changes in the organism's **body structure** e.g. shape, colour

Question 31

what are behaivioual changes

Answer 31

changes in how the organism **behaves** e.g. migration pattern, hibernation, routines, courtship display

Question 32

what are functional adaptations

Answer 32

**internal changes** within the organisms body : - ability to produce very small quantities of urine (desert rate) - reducing metabolic rate during hibernations

Question 33

what are organisms called when they live in very extreme conditions

Answer 33

extremophiles

Question 34

what are some examples of very extreme environments

Answer 34

- high temperature - high pressure - high salt concentration