Unit 7: Inheritance and Evolution pt2

Question 1

What is an Ecosystem?

Answer 1

a unit consisting of a community
of living organisms and non living components

Question 2

what is a biotic component?

Answer 2

living organisms

Question 3

what is an abiotic component?

Answer 3

The physical aspects of an ecosystem

they provide the elements which all living organisms consist

Question 4

What are the biotic factors?

Answer 4

Producers
Consumer
Saprobionts

Question 5

What is a producer?

Answer 5

Ultimate source of energy in the food chain

plants - convert light energy into chemical energy

form the organic basis of all food chains

molecules produced by photosynthesis are consumed by other organisms

• are photoautographic

Question 6

What is a consumer?

Answer 6

break down large insoluble organic compounds into smaller soluble molecules which are used to provide energy for growth

Question 7

What is a primary consumer?

Answer 7

herbivores

Question 8

What are secondary, tertiary consumers?

Answer 8

carnivores

Question 9

What are Saprobionts?

Answer 9

bacteria and fungi which break down dead organisms and are essential for the recycling of nutrients in the environment

Question 10

What abiotic factors affects size and population?

Answer 10

light
pH
temperature
water
oxygen
co2

Question 11

what forms a community?

Answer 11

all living organisms of all species

Question 12

what is a niche

Answer 12

an organism is abiotic requirement in the habitat and its position in the food web

• description of how organisms fit into the ecosystem

Question 13

how can you estimate the size of a stationary population?

Answer 13

using quadrats

Question 14

describe random sampling

Answer 14

area is divided into a grif

Coordinates are selected using a random number generator and a quadrat is placed

large number of quadrants must be used so results are representative

Question 15

when would you use transects?

Answer 15

When measuring the abundance of organisms over an area where changes in the community occur

Question 16

Describe how a belt transect is used

Answer 16

The table went along the ground in a straight line

At regular intervals, a Quadat is laid down and species within are counted

The frequency of species is recorded

Question 17

which calculations can you use to measure the abundance of an organism?

Answer 17

using it’s frequency or percentage cover

Question 18

How do you measure a frequency of an organism?

Answer 18

• The likelihood of a particular species occurring in a quadrat

OR

-The number of individuals in each quadrant

Question 19

How do you calculate percentage cover?

Answer 19

estimated by eye

The proportion of the ground area covered by the stems/leaves of the species

Question 20

How can you calculate the mean density of species in a study area?

Answer 20

total number of individuals counted
—————————————————
no. if quadrats x area of each quadrat

Question 21

What is the calculation for population size?

Answer 21

mean density x total area

Question 22

What is the mark release recapture method used for?

Answer 22

estimate the population of mobile animals

Question 23

describe the mark recapture method

Answer 23

• Capture a representative sample of organisms in a population and record the number and mark them
  (mark in a way which doesn’t affect survival)
• release back into habitat and leave them for suitable period of time to let them mix randomly
• Capture a second sample I count the number of marked individuals

Question 24

how do you calculate population size after market release recapture?

Answer 24

no. in first sample x no. in second sample
————————————————————
no. marked in second sample

Question 25

What are assumptions does the mark release recapture method rely on?

Answer 25

- organisms **mix randomly** - **sufficient time** must pass between capture and recapture to allow random mixing, **less mobile the species longer the timelapse** - organisms **disperse evenly** - **changes of population** due to immigration births/deaths are **negligible** - marking does not hinder movement/survival

Question 26

What can affect the size of populations in an ecosystem?

Answer 26

- The effect of abiotic factors - Interactions between organisms - intra- inter- specific competition - Predation

Question 27

How does light affect population size?

Answer 27

affects **photosynthesis and number and diversity** of plant species therefore, the number and type of consumers and ecosystem

Question 28

How does pH affect population size?

Answer 28

affects activity of enzymes Acidic and alkaline soils favour the growth of specific plant species

Question 29

How does temperature affect population size?

Answer 29

**metabolic processes (respiration/photosynthesis) all controlled by enzymes** - Low temperatures are a limiting factor for photosynthesis - High temperatures can cause enzyme denaturation - In aquatic habitat and increasing temperature reduces the amount of dissolved oxygen available

Question 30

What is a mutualistic relationship?

Answer 30

A relationship were two organism and benefit from the association

Question 31

What causes small communities?

Answer 31

harsh habitats and extreme abiotic factors These mean that only few species can survive

Question 32

What causes an unstable ecosystem?

Answer 32

When species diversity is low as the food web is limited

Question 33

What causes a stable ecosystem?

Answer 33

greater diversity as there’s more resources available at each trophic level the loss of one species will have a limited effect on the ecosystem

Question 34

what is an inter specific competition?

Answer 34

competition between **different species** Plants compete for light and soil etc animals compete for the same prey and water supply etc

Question 35

what is intra specific competition?

Answer 35

competition within the **same species** More intense as organisms are competing for identical resources can we stop this?

Question 36

What is Predation

Answer 36

an interspecific interaction Predator/prey relationships are important in controlling population size increasing prey results in a larger predator population but as prey ate consumed their population size begins to fall then but it’s a population decreases

Question 37

What happens if a particular prey is removed from an ecosystem?

Answer 37

it disrupts feeding relationships as the predator will then feed on another prey species

Question 38

What is primary succession?

Answer 38

The **gradual change** in plant/animal communities from **colonisation by Pioneer species** to the **climate community**

Question 39

outline primary sucession

Answer 39

- pioneers species colonise an area (lichens or algae) - when they die, they decompose and for mineral rich soil for the next group to colonise the area - new species outcompete the old organisms and change the environment making it more suitable for others ( making soil more fertile) - each of these different communities is considered part of a succession, each stage species change their abiotic environment - A series of more complex species will colonise the area eventually a climate communities formed - As the number/complexity of plant species increase theres an increase in the variety of niches/food resources with resulting changes in animal populations - Stability/diversity increases as food will become more complex

Question 40

Why may climax community not be established?

Answer 40

**agricultural practices**, e.g. grazing crop production ploughing, etc - **natural events** such as fires/floods can also prevent succession

Question 41

What is grazing?

Answer 41

seedlings of plants are continually eaten preventing any succession beyond grassland

Question 42

What is ploughing?

Answer 42

seedlings are broken up and buried preventing germination seeds of crops species are then **sown** use of herbicides maintains an established community