Populations

Question 1

Define Habitat

Answer 1

The place where an organism lives

Question 2

Define Population

Answer 2

All the organisms of one species in one place at one time

Question 3

Define Community

Answer 3

Populations of different species in a habitat at one time

Question 4

Define Ecosystem

Answer 4

All the organisms and abiotic conditions in a particular area

Question 5

Define Abiotic conditions

Answer 5

Non-living features of an ecosystem eg/ temperature, light

Question 6

Define Biotic Conditions

Answer 6

Living features of an ecosystem eg/ predators, food

Question 7

Define Niche

Answer 7

The unique role of a species within a habitat eg/ what it eats, when and where it eats

Question 8

Define Adaptation

Answer 8

A feature that members of a species have that increases their chance of survival to reproduce and pass on their genes eg/ being camouflage

Question 9

What happens to two species trying to occupy the same niche?

Answer 9

-Compete with each other -One will have an advantage over the other -The weaker species will die out until only the successful remains

Question 10

What if two species appear to occupy the same niche?

Answer 10

There will be slight differences eg/ different food sources

Question 11

What are the two types of adaptation?

Answer 11

-Physiological (processes inside the body) -Anatomical (structural features of their body)

Question 12

Define Abundance

Answer 12

The number of individuals of one species in a particular area

Question 13

Define Frequency

Answer 13

The number of samples a species is recorded in

Question 14

Define Percentage Cover

Answer 14

How much of the area investigated is covered by the species (plants only)

Question 15

Define distribution

Answer 15

Where a species is within the area investigated

Question 16

Name the five steps in taking a general sample

Answer 16

-Choose an appropriate area within the the total are being investigated -Sample randomly to avoid bias eg/ grid and coordinates from a random number generator -Appropriate sampling technique -Repeat to make more reliable -Estimate for the whole area by averaging the data collected and multiplying by the size of the whole area

Question 17

Name two methods used to investigate ground insects

Answer 17

-Pitfall traps -Pooters

Question 18

Name the three types of transects

Answer 18

-Line transect (record species touching the transect) -Belt transect (work out species frequency and percentage cover between to lines) -Interrupted transect (take measurements at intervals)

Question 19

Name the five steps in mark-release-recapture

Answer 19

-Capture and count a sample of a species -Mark them in a harmless way (give example) -Release them back into their habitat -Wait a week then take a second sample -Count how many of the second sample are marked

Question 20

What is the mark-release-recapture equation

Answer 20

total population size = (sample 1 x sample 2)/marked in sample 2

Question 21

Name two things you must consider before doing fieldwork

Answer 21

-Risk assessment -Ethical Issues (affect on environment and organisms)

Question 22

What should you include when describing data?

Answer 22

• General trends
• Example of each place it changes

Question 23

What should you include when interpreting data?

Answer 23

• Describe correlation between factors
• Suggest a conclusion
• Allow for other actors
• Suggest a reason for the conclusion

Question 24

Describe how abiotic factors affect population size

Answer 24

-With ideal abiotic factors organism can grow fast and reproduce successfully -With non ideal abiotic factors population size will decrease as more energy is used in other ways

Question 25

Name three biotic factors which affect population size

Answer 25

-Interspecific competition -Intraspecific competition -Predation

Question 26

Name the key points of interspecific competition

Answer 26

-Between different species -Competing for the same resources -Reduced resources limit population of both -If one is better adapted to its surroundings it will out-compete the other

Question 27

Name the key points of intraspecific competition

Answer 27

-Population increases with plentiful resources -Resources become limiting -Those better adapted will survive, others will die -Population declines -Less competition for resources, so cycle repeats

Question 28

Name the key points of predation

Answer 28

-Usually more prey than predator -Prey population increases so more food for predator -Predator population increases so more prey is eaten -Prey population decreases so less food for predator -Predator population decreases so less prey is eaten -Cycle returns to the start

Question 29

Define birth/death rate

Answer 29

Number of live births/deaths for every 1000 people in the population

Question 30

Give the population growth rate calcualation

Answer 30

Growth rate = birth rate - death rate

Question 31

Describe each stage of the demographic transition model

Answer 31

Question 32

Describe how to calculate population growth from a graph

Answer 32

Question 33

Describe each curve on the survival graph

Answer 33

Question 34

How do you calculate life expectancy from a survival graph?

Answer 34

-Draw a line from 50% survival -Read off the age on the x axis