Biological Diversity

Question 1

Population

Answer 1

All the organisms from the. same species living in a particular area

Question 2

Community

Answer 2

A group pf population in a particular area

Question 3

Ecosystem.

Answer 3

A community. of living organisms that interact with each other and their surrounding environment

Question 4

Biotic factors

Answer 4

The living. components of an ecosystem e.g: plants, animals, fungi, bacteria

Question 5

Abiotic factors

Answer 5

The non-living components of an ecosystem e.g: light,, temperature, wind, PH, salinity, water, shelter etc,

Question 6

Selection pressures

Answer 6

Abiotic and biotic factors can exert pressures on organisms that live in an ecosystem, when these pressures affect the. ability of an organism to survive, they are called selection pressures

Question 7

Population size definition

Answer 7

The. number of organisms of the same species in an ecosystem

Question 8

Population distribution

Answer 8

The location/ spread of an organisms within a specified environment

Question 9

Selection pressure of the cane toad

Answer 9

Few Australian predators
Few Australian diseases
Idea conditions (tempreture, humidity, salinity)

Question 10

Selection pressures of the Prickly Pear

Answer 10

No Australian Predators
Birds that spread seeds
Human influence
Ideal climate (eg. temperature, sunlight, water)

Question 11

Adaptations

Answer 11

The development of specific features of an organism that enable them to survive and reproduce In a specific environment
Structural: Relating to the physical aspects of an organism
Physiological: relating. to the internal bodily functioning of an organism
Behavioural: relating to the actions or behaviours of an organism

Question 12

Natural selection definition

Answer 12

The process whereby organisms with the traits most favourable to their environment tend to survive with higher probability, producing more offspring and pass their favourable trait to their offspring

Question 13

Darwins observations of natural selection on galapagos islands

Answer 13

Each island had a unique species of finch (14 total)
Warbler finch (narrow, pointed beaks) adapted to island with lots of insects because their beaks were to narrow to break nuts and seeds
Large ground finch (string, wide, study beaks)
Each island had different food sources
Mainland finch was the species from which the other 14 has evolved to adapt to the food sources available to them on their island.

Question 14

Darwins observations of Australian Flora and Fauna

Answer 14

1. Unrelated organisms that live in similar environments can have similar adaptations
2. Australian organisms were well adapted to the unique Australian environment

Question 15

Microevolution

Answer 15

The small-scale variation of allele frequencies within the gene pool of a species
Descendants are in the same taxonomic group as ancestors

Question 16

Macroevolution

Answer 16

The variation of allele frequencies at or above species of level
Descendants are in different taxonomic groups of ancestors
Results in speciation (the formation of new species_

Question 17

Divergent evolution

Answer 17

The process whereby one species branches out into different environments, producing organisms that possess different characteristics.
Occurs between organisms that ARE closely related
Common ancestor
Caused by different selection pressures
Leads to differences between organisms

Question 18

Convergent evolution

Answer 18

Convergent evolution is the process whereby organisms that are not closely related evolve similar structures in response to similar environmental conditions.
Occurs between organisms that are NOT closely. related
Different ancestor
Caused by similar selection. pressures
Leads to similarities between organisms

Question 19

Gradualism

Answer 19

Evolution is a continual process of change where over a long period, individuals process small changes until they split into a number of different species
Rate of evolution is constant
species gradually evolve new traits and split into new species
Not much evidence as transitional fossils are rare

Question 20

Punctuated Equilibrium

Answer 20

The evolution of species proceeds in patterns of long periods of stability followed by rapid periods during which many new species emerge and some become extinct.
supported by fossil evidence (Cambrian explosions) and theory of natural selection

Question 21

Fossil evidence

Stratigraphy

Answer 21

A process involving the comparison of the position of rock strata that contain fossils to determine the comparative time scale of their occurrence

Question 22

Fossil evidence

Index fossils

Answer 22

Fossils that existed during. limited periods of time that can be used as guides to determine the relative rage of the rocks in which they are preserved

Question 23

Radiometric dating

Answer 23

The process of determining the age of ricks or fossils from the decay of radioisotopes

Question 24

How do organisms adapt to survive

Answer 24

A sea jelly can float and keep its shape without any exo- or endoskeleton because of the buoyancy of the seawater. The tentacles they use to catch prey for food can function because they float freely. On land, the sea jelly would collapse, dehydrate, not be able to trap food and die without reproducing.

Marine fish use exposed gills with a large surface area and rich blood supply to gather enough dissolved oxygen from the water. On land, mammals have internal lungs with multiple air sacs to retain a moist, large surface area for gas exchange with their blood. Gills would not work on land because their exposed surface would dehydrate.

Question 25

Account fir the changes in prickly pear distribution in Australia over time

Answer 25

Prickly pear can reproduce from seed or pads (small pieces of tissue that have broken off). The climate in parts of inland Queensland and northern NSW is similar to the prickly pear’s place of origin. Birds can spread the seed after eating the prickly pear’s fruit. These factors, combined with a lack of selection pressures found in the original ecosystem, meant that prickly pear initially had exponential growth and a sustained population explosion shortly after its introduction to Australia. The abundance of prickly pear caused great hardship for farmers in these areas until 1926 when a biological control was introduced. The cactus moth (Cactoblastis cactorum) was brought to Australia from South America. The moth lays eggs in the prickly pear tissue and the larvae that hatch feed on and often destroy the plant. Within six years, the moth had greatly reduced the prickly pear population. The prickly pear has persisted in the cooler regions of its previous range because the cactus moth does not thrive in a cooler climate.

Question 26

Are Galapagos finishes an example of convergent or divergent evolution.

Answer 26

The many Galápagos finch species are an example of divergent evolution. Populations of a once widespread finch species have adapted to different selection pressures on different islands. Over time, the finches on each island have become increasingly divergent (different), eventually becoming different species.

Question 27

How do finches provide Darwin of evidence for his theory of evolution by natural selection?

Answer 27

After his return to England, Darwin did further study of the finch specimens he had collected from the Galápagos Islands. It became clear to him that the finches were closely related but had evolved into different species. He was able to link the beak structure of each finch species to the type of food available on the island where it was collected. Using this evidence, he surmised that natural selection had been at work––those individuals that were best-suited to their environment survived and produced the most offspring, passing on their beneficial traits to the next generation. When the ancestral finch species arrived and settled on each different island any individuals that happened to have beaks more suitable to gather the food available on that island were the ones to survive. These successful individuals reproduced and passed their genetic variation for beak shape to their offspring. Over many generations, the well- adapted beak shape became more common in the population because these individuals were better adapted to survive and reproduce. Eventually the birds on different islands with different types of food (e.g. small tough seeds compared to large soft fruit) evolved into different species.

Question 28

Explain how the evolution of courses provides both an example of a transitional series and an example of punctuated equilibrium

Answer 28

A transitional series of fossils provides a comprehensive record of microevolutionary changes as the organism accumulates differences over many generations. For example, the earliest ancestors of the modern horse were much smaller, browsed on soft leaves and fruit in rainforests and had five toes with soft pads on each foot. Teeth preserve well as fossils and tell the story of diet and age for an organism. The fossil record shows that horses evolved to become taller, stronger and have hard hooves and much tougher teeth for grinding coarse grass. The environment had changed over time from rainforest to open grassland and this selected for the horses that could graze on grass and run fast to escape predators in the open. Many fossils have been found that document these changes in small steps for horse species.
Punctuated equilibrium is a later modification to Darwin’s original theory that described gradual evolution by natural selection. It explains periods of stability for well-adapted organisms with no or little evolutionary change unless their environment changes suddenly. A sudden change in natural selection pressures causes emigration, extinction or relatively rapid evolutionary change in the population of organisms. Their fossil record will show punctuations (sudden changes) in the equilibrium of stability. In the horse fossil record, the evolution of high-crowned teeth appeared quite suddenly and reflects a transition from browsing to grazing on grass as climate change favoured grassland rather than rainforest and woodland. At this time, several species of horse became extinct. Only one line survived and it later diverged into some taller, faster, grazing species. Of these, only the Equus genus survives today.
Punctuated equilibrium differs from gradualism that refers to slow, steady evolutionary changes. With the advantage of a complete transitional series of fossils, the rate of change can be deduced.

Question 29

Why would uranium-lead dating be used instead of carbon dating

Answer 29

Uranium–lead dating is used for very old samples of rock such as this one because uranium-238 has a half-life of 4500 million years. Carbon-14 has a much shorter half-life (5730 years), making it useful for dating organic specimens up to 50 000 years old. The rock sample is much older than the carbon dating range and is more likely to contain uranium-238 than carbon-14 atoms.

Question 30

Evidence that extinction has occurred throughout the earths history

Answer 30

Fossil records provide ample evidence of extinctions having occurred throughout the long history of life on Earth. Dinosaur fossil remains are plentiful, there are many on public display and it is apparent from reliable dating that most dinosaurs did not survive the end of the Cretaceous (66 mya) when there was a mass extinction event. Pterosaurs also became extinct at this time. There are many earlier and later examples in fossil form such as the numerous trilobites, none of which survived later than 240 mya.
Many recent extinctions can be attributed to human impact. Hunting and habitat destruction are two of the main causes.