Year 9 Biology mini deck

Question 1

What are homologous structures?

Answer 1

-Have a similar structure but have different function
-Homologous structures show evidence of divergent evolution

Question 2

What are analogous structures?

Answer 2

-Structures that are similar but in unrelated organisms
-Analogous structures show evidence of convergent evolution

Question 3

What is convergent evolution?

Answer 3

Convergent evolution on the other hand is when two unrelated species develop similar traits because they live in similar environments.

e.g. Flying lizards and flying squirrels

Question 4

What is the difference between convergent and divergent evolution?

Answer 4

Divergent evolution is when individuals in one species, or closely related species, acquire enough variations in their traits that it leads to two distinct new species. Convergent evolution on the other hand is when two unrelated species develop similar traits because they live in similar environments.

Question 5

What is the difference between a homologous structure and an analogous structure?

Answer 5

Homologous structures - structures that are similar in organisms because they are inherited from a common ancestor but may function differently. Analogous structures - structures that are similar in unrelated organisms.

Question 6

What is a selection pressure?

Answer 6

A factor in an organism’s environment that removes unsuited individuals from the population

Question 7

What is a selective advantage?

Answer 7

The characteristic of an organism that gives an organism a greater chance of surviving and reproducing

Question 8

What is adaptive radiation?

Answer 8

A form of divergent evolution where a number of different species form from a single ancestor

Question 9

What evidence is there that evolution occurred?

Answer 9

-Structural morphology
-Fossils
-DNA

Question 10

Structural morphology

Answer 10

-Fossilized organisms that have features in common with present day organisms support the theory of evolution

Question 11

Fossils

Answer 11

-Fossils help provide evidence of change and evidence of organisms that no longer exist

Question 12

DNA

Answer 12

-Found in bones, skin and preserved remains (can degrade over time- not usually found in fossils)

Question 13

Steps for fossilization

Answer 13

1. A hard bodied organism is rapidly buried in sediment
2. Soft tissue decomposes
3. Mineralization occurs in the hard parts of the organism (minerals from the sediment, replace the bone over time)
4. Pressure turns sediment into rock

Question 14

Define fossils

Answer 14

Remains or traces of pre-existing life preserved in ice, rock or amber

Question 15

Conditions for fossilization

Answer 15

Fossils will only form when:
-the organism has hard parts
-the remains are hidden from scavengers, and undisturbed for a long time
-there is no oxygen present so no decay can occur
-the temperature is low so no decay occurs
-there is high pressure

Question 16

Why would there be gaps in the fossil record?

Answer 16

-Conditions for fossilization weren’t met
-Fossils have been destroyed/eroded
- Fossils haven’t yet been found

Question 17

Explain which fossil is the oldest (rock diagram) ?

Answer 17

-Because sedimentary rock is formed in layers one on top of another and fossils buried deeper are older than those that are shallower
-Then the trilobite is the deepest fossil show here
-Therefore, the trilobite is the oldest fossil

Question 18

Explain which species is the most closely related to a human (genome diagram)?

Answer 18

-Because closely related species have fewer differences in their DNA spquences
-Then species A and B have one nucleotide difference, species A and C have 5 differences and species A and D have 3 differences
-Therefore species A and B are most closely related

Question 19

What evidence may phylogenetic trees be constructed from?

Answer 19

-fossils, DNA or structural morphology

Question 20

Explain which species is most closely related to the common bottlenose dolphin

Answer 20

Because closely related species share a more recent common ancestor
-Then the Burana dolphin and common bottlenose dolphin show the most recent branching and a most recent common ancestor
-Therefore the Burana dolphin is the most closely related

Question 21

What are three trends in human evolution?

Answer 21

-Brain size has increased which means skull size has also increased
-Arm to leg ratio has decreased
-Pelvis shape has changed into more bowl-like

Question 22

Why have humans evolved in this way skeletally?

Answer 22

-Shorter arms and longer legs are better adapted for bipedalism
-Pelvis became shorter and more “bowl shaped” , also adapted for bipedalism
-Also became narrower with a more circular birth canal
-Larger skull for larger brain
-Lessening of brow ridge
-Flattening of face
-Smaller teeth

Question 23

Define selective breeding?

Answer 23

Choosing parents with particular characteristics to breed together and produce offspring with more desirable characteristics

Question 24

Steps in artificial selection (example of Belgian blue cow)

Answer 24

1. identify the desired trait( of having a high muscle mass)
2. Select males and females to breed together
3. Breed
4. Repeat over many generations until desired traits are obtained

Question 25

Does artificial selection lead to evolution?

Answer 25

Yes as there is a change in allele frequency over time.

Question 26

What are the advantages of selective breeding?

Answer 26

Economic advantage : Better or higher quality
e.g. corn has been selectively bred to have a higher mas of grain
Animals can be bred that do not cause harm
e.g. dogs have been bred to be hypoallergenic

Question 27

What are disadvantages of selective breeding?

Answer 27

-High levels of inbreeding
-Low levels of genetic variation
-Traits that are desirable for humans may be harmful in certain organisms
e.g. pugs have severe breathing problems

Question 28

What are some differences between natural and artificial selection?

Answer 28

-The selective pressure in natural selection is environmental, whereas in artificial selection the selection pressure is introduced by humans

-In natural selection, individuals with a higher biological fitness have a selective advantage, whereas in artificial selection, individuals with desired characteristics are able to reproduce and pass on their alleles

Question 29

What is a GMO?

Answer 29

A genetically modified organism is any organism whose genetic material has been altered using a genetic engineering techniques

Question 30

What are transgenic organisms?

Answer 30

Transgenic organisms are organisms that have had a gene from another species inserted into their own genetic sequence e.g. glow fish have jellyfish gene