B15. Ecology and Ecosytems

Question 1

Ecology is…

Answer 1

The branch of Biology that studies organisms and their relationships with the living and non-living environment in which they live.

Question 2

What are the 4 levels of organisation of organisms in an ecosytems?

Answer 2

Individual organism –> Population –> Community –> Ecosystem

Question 3

Define the term ‘population’

Answer 3

A population is all the organisms of the same or closely-relatedspeciesin an area.

Question 4

Define the term ‘community’

Answer 4

A community where multiple populations (ofdifferent species) living and interacting in thesame area.

Question 5

What is an ecosytem?

Answer 5

An ecosystem is the name given to a community or group of living organisms (animals and plants) that live in a particular location. It is the interaction between living and non-living things in this environment.

Question 6

What is a biotic factor and list 3 examples.

Answer 6

Living factors (Biotic factors):
e.g. availability of food, predators, pathogens, animals, plants etc.

Question 7

What is an abiotic factor and list 3 examples.

Answer 7

Non-living factors (Abiotic factors):
e.g. temperature, light intensity, moisture levels, oxygen levels, soil pH and mineral content, wind intensity, carbon dioxide levels, oxygen levels.

Question 8

Define the term ‘habitat’

Answer 8

A habitat is the natural home or environment of an animal, plant, or other organism.

Question 9

What is meant by the term ‘competition’?

Answer 9

When there are limited resources for a plant or animal to survive and reproduce they ‘compete’ for these resources.

Question 10

Name the 2 types of competition.

Answer 10

1) INTRA-specific competition
2) INTER-specific competition

Question 11

What is meant by ‘intra-specific’ competition?

Answer 11

Competition between members of thesamespecies e.g. 2 lions fighting over territory.

Question 12

What is meant by ‘inter-specific’ competition?

Answer 12

Competition between members ofdifferentspecies e.g. a lion and a tiger

Question 13

Name 3 things animals compete for.

Answer 13

• Mates
• Territory
• Food

Question 14

Name 3 things plants compete for

Answer 14

• Space
• Light
• Water
• Mineral ions

Question 15

What is meant by the term ‘inter-dependence’?

Answer 15

Within a community, each species depends on other species for food, shelter, pollination, seed dispersal etc.

If one species is removed it can affect thewhole ecosystem.
This is calledinterdependence.

Question 16

What is a ‘stable community’?

Answer 16

Astablecommunity is one where all the species and environmental factors are in balance so that population sizes remain fairly constant.

Question 17

Describe the relationship between predators and prey

Answer 17

The predator-prey relationship is a cyclical relationship.
The size of each population directly affects the size of the other.

Question 18

Why do organisms (animals & plants) need adaptations?

Answer 18

Organisms have features (adaptations) that enable them to survive in the conditions in which they normally live.

Question 19

Name 3 types of adaptations an animal may have

Answer 19

Structural adaptations

Behavioural adaptations

Functional adaptations

Question 20

Even thought a polar bear is very large, why does it have a SMALL surface area: volume ratio?

Answer 20

The polar bear does not have enough surface area on the outside to fill the even larger volume on the inside.

Question 21

List some general adaptations for an animal living in a COLD environment

Answer 21

• Colouring is camouflaged to the environment
• Small surface: volume ratio
• Larger body size
• Streamlined shape (if lives in water)
• Layer of blubber
• Small ears

Question 22

List some general adaptations for an animal living in a HOT environment

Answer 22

• Larger surface area: volume ratio
• Colouring is camouflaged to the environment
• Smaller body size
• Thin layer of fur (less insulation)
• Large ears

Question 23

The cactus plant lives in very hot, dry conditions in the desert. Describe some of the adaptations of cacti.

Answer 23

• Waxy layer: to prevent water evaporating
• Thin spines instead of leaves to reduce water loss via transpiration
• Extensive root systems underground to maximise water absorption

Question 24

Describe 2 examples of an ‘extreme environment’

Answer 24

1) Very high or low temperatures
2) Very high or low pressures
3) Very high salt concentration.

Question 25

Organisms that can survive and reproduce in an extreme environment are called _______________.

Answer 25

Extremophiles

Question 26

Which types of habitat may have an ‘extreme environment’?

Answer 26

An example of habitats where extremophiles are found aredeep-sea volcanic vents, where the conditions are extremelyhot, under highpressureand there is no sunlight.

Question 27

What is the formula for estimating the total number of organisms in an area?

Answer 27

(Total area of field/area of one quadrat) x mean number of organisms

Question 28

How can a quadrat be used to estimate total population size of an area?

Answer 28

By randomly placing quadrats within a habitat and counting the number of individuals or species within each quadrat, scientists can calculate an average density and use this to estimate the total population size of the habitat.

Question 29

What is random sampling?

Answer 29

Random sampling involves selecting sample areas or individuals randomly within a habitat, ensuring that each part of the habitat has an equal chance of being sampled.

Question 30

What could you use to ensure the areas sampled are random?

Answer 30

A random number generator to generate random coordinates.

Question 31

How could you make your sampling investigation more precise?

Answer 31

Repeat with more quadrats. This will make the results more precise and more representative of the entire area.

Question 32

Explain why it’s important to use random sampling when using quadrats.

Answer 32

Random sampling ensures that the data collected is representative of the entire habitat, reducing bias and providing a more accurate estimate of population size or distribution.

Question 33

What precautions should be taken to minimize bias when using quadrats?

Answer 33

Precautions include randomizing the placement of quadrats, ensuring quadrats are large enough to capture variation in the habitat, and repeating sampling multiple times to account for variability.

Question 34

How can quadrats be used to study changes in biodiversity over time?

Answer 34

By repeatedly sampling the same area with quadrats over time, scientists can observe changes in the diversity and abundance of species, providing insights into ecosystem health and dynamics.

Question 35

What is a transect and how is it related to quadrat sampling?

Answer 35

A transect is a line or path (usually just a tape measure!) along which quadrats are placed to sample a gradient or change in habitat characteristics, such as from a rocky shore to the sea water.

Question 36

What are some limitations of using quadrats for ecological sampling?

Answer 36

Limitations include the inability to sample mobile or hidden organisms, the potential for bias if quadrats are not placed randomly, and the time and effort required for large-scale studies.