Ecology- Living Organisms In Their Environment

Question 1

What is ecology?

Answer 1

The study of the interrelationships of living organisms with each other and their environment

Question 2

What is the environment?

Answer 2

The combination of factors that surrounds and acts upon an organism. These factors can be divided into abiotic and biotic factors.

Question 3

What are biotic and abiotic factors?

Answer 3

Biotic- all the living organisms that are present (predators, prey, parasites)
Abiotic- all the chemical and non living factors.

Question 4

What is a habitat? Give an example.

Answer 4

The place where a particular organism lives.
Habitat of an earthworm- soil

Question 5

What is a specie and give example?

Answer 5

A group of organisms of common ancestry that resemble each other and normally capable of interbreeding to produce a fertile offspring
Dog specie- German shepherd

Question 6

What is a population and give example?

Answer 6

All the members of a particular speices living together in a particular habitat.
example- sea urchins living together on the sea grass bed

Question 7

What is a community and give an example

Answer 7

All the populations of different species living together in a particular habitat.
example- a woodland community consists of plamts animals and decomposers that inhabit the wood.

Question 8

What is an ecosystem and give an example

Answer 8

A community of living organisms interracting with each other and their abiotic environment.
example- pond, coral reef

Question 9

What is a niche?

Answer 9

The position or role of an organism in an ecosystem

Question 10

What is the aim of studying an ecosystem?

Answer 10

The aim of studying an ecosystem is to identify different species of plants and animals, find out where they live, determine their numbers and their relationship with each other and their abiotic factors.

Question 11

When collecting organisms what are somme precautions?

Answer 11

• organisms should not be damaged unecessarily
• a few should be collected and returned to their original position is possible
• habitat should be left as undisturbed as possible.

Question 12

What are some methods to sample organisms?

Answer 12

pooter
pitfall trap
plankton net
net
tulgreen funnel

Question 13

What are pooters for?

Answer 13

small animals in small places

Question 14

What are pitfall traps for?

Answer 14

walking or crawling animals

Question 15

What is the tulgreen funnel for?

Answer 15

small animals in soil samples or leaf litter

Question 16

What is a net for?

Answer 16

flying insects and aquatic animals

Question 17

What is a quadrat and give its purpose

Answer 17

A quadrat is a square frame whose area is known. (1m2). It is thrown at random several times in the ecosystem. Its used to measure stationary or slow movig oraganisms. The number of organisms within the quadrat can be counted. It can make into a grid using a string. The purpose of the quadrat is to study the distrubution and abundance of slow moving or stationary organisms in a uniform ecosystem.

Question 18

What is a point quadrat and how is it used?

Answer 18

used to give a more objective assessment of cover. A pin is dropped through a low standing frame onto the vegetation and if a pin touches a plant then a hit is recorded.

Question 19

What are some disadvantages of using quadrats?

Answer 19

• time consuming
• labor intensive
• can harm organisms if it lands on them
• cannot completely illiminate bias since the quadrat can be thrown in a place of choice.

Question 20

What are some advantages of using quadrats?

Answer 20

• they allow reseachers to study plants and animals over a large area
• the are inexpensive
• they require no skill to use

Question 21

What is a line transect?

Answer 21

Normally a tape or string thats marked at intervals and placed along an ecosystem. The organisms that touch the line at the intervals are recorded. Its used to study stationary or slow moving organisms.

Question 22

What is a bell transect?

Answer 22

A strip of fixed width thats made by placing two line transects parallel to each other and the organisms in between are counted.
Alternatively, A quadrat can be placed alongside a line transect and the organisms within its boundaries are counted. The quadrat is then moved along the line and is repeated are regular intervals.

Question 22

What are 2 ways to sample in an environment?

Answer 22

Random sampling
Systematic sampling

Question 23

What is random sampling?

Answer 23

involve methods that are not specific and structured.

Question 24

What is systematic sampling?

Answer 24

Involve methods that are specific and structured. It involves a clear set of steps that must be followed.

Question 25

How can we estimate population sizes?

Answer 25

- using results from quadrats - capture-recapture method

Question 26

What results can we get from quadrats?

Answer 26

species density species frequency population size percentage coverage

Question 27

How do calculate species density?

Answer 27

total number of individual/area of quadrat x #of throws unit- per m^2

Question 27

How do you calculate species frequency?

Answer 27

of times organism is seen/# of throws

Question 28

How do you calculate poulation size?

Answer 28

species density/total area of sample field

Question 29

What is the use of the capture-recapture method?

Answer 29

used to estimate population sizes of moving animals

Question 30

How do you do the capture and recapture method?

Answer 30

Animals of a species are collected, counted and marked. They are placed back into the same area and given time to mix back with their orginal poulation. A second sample is collected and the marked animals are counted.

Question 31

Whats the formula to estimate the population size using the capture-recapture method?

Answer 31

of organisms captured in first sample x #of organisms captured in second sample/#of marked organisms recaptured in the second sample

Question 32

Whats another name for the capture-recapture method?

Answer 32

Lincoln Index.