Lecture 7

Question 1

Define ecology

Answer 1

Interaction between organisms and their environment (abiotic and biotic environment)

Question 2

Define species

Answer 2

Two organisms are separate species if they cannot breed and produce viable offspring

Question 3

What is the biological species concept?

Answer 3

Male and female of different species can’t breed, morphological species concept, molecular species concepts

Question 4

Define a population

Answer 4

A group of individuals of a species that are living and interacting in a particular area (one species)

Question 5

Define a community

Answer 5

An association of populations of different species in the same area (several species)

Question 6

Define an ecosystem

Answer 6

A community of organisms plus their physical environment (abiotic factors- Mountains, Rivera etc.)

Question 7

What is the biosphere?

Answer 7

All the world’s ecosystems comprise the biosphere- all living organisms on Earth plus the environments in which they live

Question 8

What do ecological studies often include?

Answer 8

Both the biotic (living) and abiotic (physical) components of natural systems

Question 9

Give the order of the biological process hierarchy

Answer 9

Individuals-> populations-> communities-> ecosystems-> biosphere

Question 10

Give the barriers between plant and animal populations

Answer 10

. Rivers 
. Valleys 
. Mountains 
. Unsuitable habitats or environments 
. Roads/ man-made features 
. Food availability

Question 11

What are the four processes that determine whether plant or animal populations get larger or smaller?

Answer 11

. Birth
. Death
. Immigration (the number of new individuals that come into a population)
. Emigration (the number of individuals that leave a population)
(In a population in ant period e.g. a year)

Question 12

How do the four basic population processes (determine whether plant or animal populations get larger or smaller) occur?

Answer 12

Simultaneously within the population

Question 13

What is unlimited growth?

Answer 13

. All plant or animal populations have the potential to undergo unlimited growth or decline
. Even slow reproducing species
. E.g. Darwin estimated: 2 elephants, 500 years= 15 million animals

Question 14

What are the limits to population growth in time and space?

Answer 14

. Physical environment 
. Climate conditions 
. Other species
. Human activities 
. Disease 
. Invasive species 
. Evolutionary history 
. Disturbance 
. Interactions of above with each other

Question 15

What happened with the invasive species Opuntia stricta and Cactoastics cactorum?

Answer 15

. Native to South America, both still found in Australia but in small numbers
. Introduced in the 19th century because people thought they would make a good natural fence and can be used in dying fabrics
. Quickly became established
. So as a last resort they decided to introduce a moth that eats the plant (prickly pear- Cactoblastis cactorum) and it got rid of them without many of implications

Question 16

How do you estimate population abundance and distribution?

Answer 16

. Area-based counts (can be extended to volume)
. Popular for sessile organisms; vegetation studies using quadrants of any shape of size (count all the individuals in an area)- Marine animals such as sea urchins
. Large mammals in aerial surveys (go out in a helicopter and count all of the big animals)?

Question 17

Explain how area-based extended to volume methods of estimating population abundance and distribution work and what they are particularly useful for

Answer 17

Particularly useful for insects.

Use a machine where you suck a volume of air in, see how many insects are in that volume and multiple it

Question 18

Explain how the most popular method of estimating population abundance, transects-based counting, is carried out

Answer 18

Walk along a line and count everything they see, there is an equation for this

Question 19

Explain the capture, mark, release, recapture method of estimating abundance of species works

Answer 19

. Huge range of tagging methods available for ‘mark-recapture’ studies
. Recapture does not always mean physical recapture
. Birds, mammals, fish, insects all studied
. E.g. tagging of salmon near dorsal fin