Module 3 and 4

Question 1

What is an ecosystem?

Answer 1

The interactions between biotic and abiotic factors within an area.

Question 2

What are selective pressures?

Answer 2

Factors that affect an organism’s ability to survive in a given environment.

Question 3

What are the 3 types of biodiversity? (define them)

Answer 3

genetic diversity - the diversity of genetic characteristics in the genetic make-up a species.

species diversity - is a measure of the
diversity of different species in an ecosystem.

ecosystem diversity - the variation of
different ecosystems found in a region.

Question 4

What are abiotic selective pressures (give examples)

Answer 4

(non-living) Temperature, salinity and nutrient availability in soil.

Question 5

What are biotic selective pressures (give examples)

Answer 5

(living) Availability of food, mates predators and competition.

Question 6

Changes in a population of cane toads due to selection pressures:

Answer 6

Cane toads were introduced to try to reduce insect attacks on sugar cane crops.
They are an invasive species that thrive due to a lack of negative selection pressures. They also increased competition for native species.

This allowed their population to rapidly increase.

Question 7

Define Population:

Answer 7

A group of the same species in an ecosystem

Question 8

Define Species:

Answer 8

A group of organisms that can interbreed

Question 9

Define Speciation:

Answer 9

The formation of a new species (a group of organisms that can breed with each other)

Question 10

Whats an adaptation?

Answer 10

A feature that an organism inherits that enables it to survive in a specific environment.

Question 11

What are the 3 types of adaptations? (give examples)

Answer 11

Structural - physical features (e.g thick fur to survive the cold)

Physiological - internal body process (e.g. snakes produce venom for protection)

Behavioural - How an organism acts (e.g. penguins huddle to conserve warmth)

Question 12

What are the 4 steps of The Theory of Evolution by Natural Selection?

Answer 12

Genetic variation existing within the species

That variation can be inherited

Those organisms with characteristics that are selected for will survive and go on to reproduce

Competition between organisms and survival of the fittest

Question 13

Define macroevolution and give an example:

Answer 13

Evolution of organisms which takes place over millions of years and results in new species.

EXAMPLE The evolution of the platypus, dinosaurs to Birds and Homo sapiens.

Question 14

Define microevolution and give an example:

Answer 14

Occurs over shorter periods of time and results in changes within populations, not new species. Results in varieties or races.

EXAMPLE Microevolution is the evolution of the horse 50 million years ago from a dog-sized forest dwelling animal. Antibiotic resistance in bacteria.

Question 15

Define Convergent evolution and give an example:

Answer 15

When two unrelated species develop similar characteristics because they are subjected to the same selection pressures.

EXAMPLE Dorsal fins in sharks and dolphins to increase stability when swimming.

Question 16

Define Divergent evolution and give an example:

Answer 16

When closely related organisms develop different characteristics because they are subjected to different selection pressures.

EXAMPLE Darwin’s finches

Question 17

What’s punctuated equilibrium?

Answer 17

It suggests that evolution occurs in short bursts of rapid change, followed by long periods of stability within populations.

Question 18

What’s gradualism?

Answer 18

suggests that evolution occurs over long periods of time when populations slowly diverge by accumulating changes in characteristics due to different
selection pressures.

Question 19

How did the first eukaryotic cells appear?

Answer 19

When larger prokaryotic cells started to ingest smaller cells. This led to the cells starting to develop specialised compartments which became membrane-bound organelles such as the mitochondria.

Question 20

Define Palaeontology:

Answer 20

The study of fossils.

Question 21

Define relative dating:

Answer 21

Is used to determine how old something is in relation to other objects (fossils found up higher in rock are younger than the lower fossils)

Question 22

Define absolute dating:

Answer 22

Is used to determine the specific age of rocks and fossils by measuring the half-life of radioisotopes.

Question 23

What’s comparative anatomy?

Answer 23

The comparative study of the body structures of different species.

Question 24

What’s comparative embryology?

Answer 24

The study of the similarities and differences in the embryos of different species.

Question 25

What’s biogeography?

Answer 25

Biogeography is the study of the geographical distribution of organisms.

Question 26

What is competition?

Answer 26

When two or more organisms have one or more resources in common (e.g. food, shelter and mates), they can be between or within species.

Question 27

Define Allelopathy:

Answer 27

When a plant produces chemicals that can be detrimental or beneficial to other organisms.

Question 28

What is parasitism?

Answer 28

Relationships where one species benefits and the other is harmed (e.g tapeworms and ticks)

Question 29

What is mutualism?

Answer 29

Relationships where both species
benefit (e.g. algae within coral reproduce and photosynthesis and give coral their colour)

Question 30

What is commensalism?

Answer 30

Relationships where one species benefits and the other is unaffected (e.g. adhere to the surface of whales to be transported to areas rich in food)