M3 - Biological Diversity

Question 1

What is a selection pressure?

Answer 1

An agent that affects an organism’s ability to survive in an environment. This can be positive or negative, causing genetic change in a population

Question 2

What is the difference between density dependent and density independ factors? Give examples

Answer 2

Dependent are affected by population:
PANDA
P-redators, A-availability or resources, N-nutrient supply, D-disease, A-accumulation of wastes

Independent are not affected by population: PAW
P-phenomena. A-abiotic factors, W:weather conditions

Question 3

What are biotic factors and how do they affect the ecosystem?

Answer 3

Biotic factors are living things and processes within an ecosystem.
Predation: more predators = less prey
Competition: More competition = less resources (habitat, mates)
Food availability: low food = decrease abundance
Disease = reduced abundance

Question 4

What are abiotic factors and how do they affect the ecosystem?

Answer 4

Abiotic factors are non-living parts of an ecosystem
Light: Needed for plants to photosynthesis which animals eat
Temperature: Dormancy caused by unfavourable weather
Water: Needed in diet and for plants to grow
oxygen: organisms that can inhabit

Question 5

Explain how Cane Toads have caused a change in population of organisms

Answer 5

Cane toads were introduced into Australia as a biological control for cane beetles. The population rapidly increased and quicky became a pest due to them being able to cover land fast and having no natural predators. This has harmed many native Australian flora and fauna due to their poisonous nature.

Question 6

How has Prickly pear distribution been affected?

Answer 6

Prickly pears were introduced to feed insects before it rapidly produced and caused massive infestation. Cactoblastis larvae were released which was effective on killing most of the prickly pear.

Question 7

What is an adaptation and how are they significant to organisms?

Answer 7

Adaptions are features that a species inherits which suit their environment for survival and to reproduce.

Question 8

Explain and give examples of the 3 types of addaptations

Answer 8

Structural: how an organism is built (spikes on echidna)
Physiological: how an organims functions (producing concentrated urine)
Behaviours: how an organisms acts (noctural, migration)

Question 9

What is Darwin’s theory?

Answer 9

Darwin’s theory of evolution by natural selection explains the change in species over many generations due to natural selection of favourable traits. Variation allows more offspring produced to survive, Those with the favourable trait are adapted to their environment and survive to reproduce, passing the trait to the next generation. The trait overtime increases in population.

Question 10

What did Darwin observe in regards to the Finches of Galapagos Islands?

Answer 10

Darwin studied finches on the Galapagos island where he found many birds with differing beaks and features. By studying them, he hypothesised they came from a common ancestor but branched off into different species because of their varying environments and selection pressures.

Question 11

What did Darwin observe in regards to Australian flora and fauna?

Answer 11

Darwin observed that many mammals in Australia revealed similarities with European mammals living in similar environments. This led to the idea that animals evolved to become similar (convergent evolution). Similar variations possessed would be favoured by natural selection and the trait would be bred and passed to the next generation.

Question 12

Explain the evolution of the horse?

Question 13

What is biodiversity and what are the three levels of it?

Answer 13

The variety of life on Earth in any given area
-Genetic:
-Species
-Ecosystem

Question 14

Explain the origin of life

Answer 14

Inorganic molecules formed organic molecules which reacted with one another to form complex compounds. membranes formed, giving rise to prokaryotes which ingsted each other to for, membrane-bound organelles and then eukaryotic cells.

Question 15

What is microevolution?

Answer 15

Microevolution is the small scale variation of allele frequency in the gene pool within a same species. This can be caused by
-Gene flow
-Genetic drift
-Mutation
-Selection prssure

Question 16

What is macroevolution?

Answer 16

The variation in allele frequency at or above species level. This occurs from the accumulation of microevolutionary changes.
It is also caused by genetic drift, gene flow, mutation and selection pressure

Question 17

Explain the microevolutionary changes of a horse

Answer 17

The first ancestor of the horse fed on soft leafy vegetation and had small teeth and molars. As the climate became cooler and dried, grass became their food source so their premolars became molars with more ridges to chew. Teeth became taller for grazing and face structure changed to accommodate this. Their feet also became more flexible and the middle toe became increasingly wider as their outer became smaller to bear the weight for running on harder ground. Elongated feet bones allowed longer strides for greater speed and endureance.

Question 18

Explain the microevolutionary changes of a platypus

Answer 18

Platypus began as aquatic animals with very large teeth to feed on small turtles and fish.. As their food source changed, their teeth became smaller and they became more specilaised.

Question 19

What is convergent evolution?

Answer 19

The process of evolution in which organisms without a recent common ancestor develop similar features in response to having similar selection pressure from their environment. For example sharks are cold blooded fish while whales are walm blooded mammals who have both adapted a streamline body and dorsal fin to survive in the water.

Question 20

What is divergent evolution

Answer 20

The process of evolution in which organisms who are closely related and share a common ancestor develop differing traits and become less similar due to being exposed to different selection pressures. The Galapgos finches come from a common ancestor but became geographically separated and face different food sources which made their beaks vary in size.

Question 21

Compare punctuated equilibrium with gradualism

Answer 21

Punctuated equilibrium is evolution that occurs through rapid bursts of change followed by longpauses of stability within a population. Contrastingly, gradualism proposes evolution occurs slowly and constantly by diverging and accumulation of characteristics from selection pressures.

Question 22

What are the types of evidence for evolution?

Answer 22

Biochemical evidence, comparative embryology, comparative anatomy, biogeography, fossils

Question 23

Explain the evidence for evolution from biochemistry

Answer 23

Species that are more closely related are more biochemically similar as their base sequences and amino acids have fewer difference.
DNA hybridisation involves take DNA from 2 species, joining them and then heating them. This strans separate and join back together when cooled. The more mismatches in the DNA, the less temperature needed to separate them.

Question 24

Explain the evidence for evolution from comparative anatomy

Answer 24

Mammals, birds, reptiles and amphibians have the same arrangement of bones (pentadactyl) indicating a common ancestor. While they all perform different functions, it still has the basic structure of femur, radius, ulna, carpals, metacarpals and phalanges.

Question 25

What is a vestigial structure?

Answer 25

A structure in an organism that has no use to it. In humans, these are the appendix and wisdom teeth.

Question 26

Explain the evidence for evolution from comparative embryology

Answer 26

Observing embryos show how organisms exhibit similar developmental characterisitics, suggesting a common ancestor. For example, human embryos begin with tails suggesting a link to fish while humans no longer have them. Pharangeal arches resemble gills while humans do not have them.

Question 27

Explain the evidence for evolution from biogeography

Answer 27

The movement of continents explain the geographical distribution of species with a common ancestor. For example, large flightless birds are separated on continents once joined.

Question 28

How ate fossils dated to produce evidence?

Answer 28

Radiometric dating: Carbon-14 is in plants and animals and turns into nitrogen. Scientist can estimate how long organisms have been dead for.
Stratigraphy: Finding relative age using known age of close rock layer.
rock layer come newer as it piles upward. Fossils at the bottom are more simple while fossil higher up are more complex. This shows how some species have gone extinct while others were not around.

Question 29

How have cane toads evolved?

Answer 29

-Rapid reproduction rate
-Breeding all year
-No predators
-Wide food source

Question 30

What is antibiotic resistance?

Answer 30

Bacteria being unaffected by antibiotics. This is because bacteria reproduces rapidly and has variations among them. They are able to transfer this muation just by touching, spreading this resistance.

Question 31

What are some symbiotic relationships?

Answer 31

Interaction between two organisms living close where at least one benefits from it
-Mutualism: both benefit
-Commensalism benefit, no affect
-Parasitism: benefit, suffer

Question 32

What is an ecological niche?

Answer 32

The part of an ecosystem that an organsim ocupies.

Question 33

What are some sampling techiques?

Answer 33

Transects: line that runs through an area to count and map numbers, showing how diversity changes.
Quadrats: Defined area randomly placed to measure distribution, abundance or density.
Capture-release: sample 1 is captured, tagged and release. Sample 2, found how many tagged.
N = first capture x second capture/ recapture

Question 34

Explain a recent extinction event