Science Exam

Question 1

What is the universe?

Answer 1

All the matter and energy that has and will exist in space and time 

Question 2

List common astronomical objects

Answer 2

planets, stars, comets, galaxies

Question 3

What is a vestigal trait?

Answer 3

Features that a species inheirts that is less function than in the ancestor
Example is claws on bird wings, and human appendix

Question 4

What is divergent evolution, and give an example?

Answer 4

When two organisms diverge from a common ancestor due to different selection pressures
Example is dog and fox diverging from wolf

Question 5

What is convergent evolution, and give an example?

Answer 5

Two species evolve to have similar characteristics due to the environment. NOT a common ancestor
Examples are shark and dolphin bodies

Question 6

What are the five points in Natural Selection?

Answer 6

Variation - There are genetic differences in the population
Birth rate - More offspring are produced than survive
Inheritance - Traits are inherited over generations through DNA
Selection - Some variations are more favourable. Favourable traits help individuals survive and reproduce
Time - Frequency of traits in population change over time

Question 7

What are the four stages of speciation?

Answer 7

Varitation - Difference between individuals (colour, size)
Isolation - Population is split into two and cannot interbreed
Selection - Two populations experience different selection pressures
Time - After thousands of year, if the two populations met again they can longer interbreed. They are two separate species.

Question 8

What did Lamarck’s Theory state about how changes/mutations occur in organisms?

Answer 8

Changes occur during an organisms life by altering their behaviour in response to environmental changes
Disproven because characteristics acquired in a lifetime do no affect genetic make up

Question 9

What did Lamarck’s Theory state about evolution over generations?

Answer 9

Changes modify organs, which are inherited by their offspring. Believed this “improves” them

Question 10

Compare a giraffe’s long neck between Lamarck and Darwin’s Theories

Answer 10

Lamarck: The giraffe developed the long neck by stretching their necks to reach the high leaves. This motion altered neck, and offspring inherited the long neck

Darwin: Giraffe that had long neck mutation survived, while those with short neck didn’t. This was inherited to offspring.

Question 11

How does the Big Bang Theory differ from the Steady State Theory?

Answer 11

The Big Bang theory states that universe started at an infinitely hot and dense point, and that the density decreases.
The Steady State theory states that the universe always existed, and that the density stays the same as it expands.

Question 12

Why do covalent bonds have low melting/boiling points compared to ionic bonds?

Answer 12

Because covalent bonds have weak intramolecular bonds so less force is require to break down the bonds.

Ionic bonds have strong electrostatic forces between molecules so they are harder to break down.

Question 13

What happens when electrons jump to higher shells and why do they jump?

Answer 13

When electrons jump to higher shells their energy level increases. They jump to a higher energy level when energy like heat is added. When they jump back down to the lower energy level they release energy, usually in the form of light.

Question 14

What is an embryo?

Answer 14

It is the initial stage of developement for a multicellular organism.

Question 15

What does comparative biochemistry do?

Answer 15

It reveals similarities in organisms through DNA and proteins (molecular make up)

Question 16

How does geographical distribution provide evidence for evolution?

Answer 16

Distribution of closely related species on continents that were once joined together, show that new species can adapt when exposed to different environments due to plate tectonics over time

Question 17

What is the first thing to form for vertebrate embryos?

Answer 17

Gills

Question 18

What is an allele?

Answer 18

One of two or more versions of DNA sequence at a given genomic location.
They determine mutations in species.

Question 19

What are the characteristics of an elliptical galaxy?

Answer 19

Spherical to egg shaped, groups of old stars

Question 20

What are the characteristics of an irregular galaxy?

Answer 20

Shapeless, no symmetry
Mix of young and old stars

Question 21

What are the characteristics of a spiral galaxy?

Answer 21

Flat disk with spiral shaped arms, bulge, made up of young stars

Question 22

What elements make up the essential amino acids?

Answer 22

CHONS
Carbon, hydrogen, oxygen, nitrogen, sulfur

Question 23

Stages of a low mass star?

Answer 23

Nebula, protostar, main sequence, red giant, planetary nebula, white dwarf, black dwarf

Question 24

Stages of a high mass star?

Answer 24

Nebula, protostar, main sequence, super red giant, supernova, neutron star, black hole

Question 25

Describe the process of nucleosynthesis

Answer 25

When nuclei join together during nuclear fusion to create new elements

Question 26

Describe the stages of the universe following the Big Bang

Answer 26

Big Bang, first particles, first nuclei, first elements, first light, first stars, first galaxies, dark energy, modern day

Question 27

What is fossilisation, and how does it provide evidence for evolution?

Answer 27

The process in which remains of a living organism are preserved in the earth's crust over millions of years Supports evolution because it provides a record for how evolution occurred over time

Question 28

Why are there gaps in the fossil record?

Answer 28

The fossil record is incomplete due to decay, rare conditions and erosion

Question 29

What are vestigal organs and how do they support evolution?

Answer 29

Structures in organisms that have lost most or all of their function through evolution. Supports evolution by showing that organisms have inherited structures from their ancestors and have changed over time.

Question 30

What are Ubiquitous proteins?

Answer 30

proteins that are found in nearly all cells and organisms. They play essential roles in basic cellular processes necessary for life, such as metabolism, cell structure, and gene expression.

Question 31

What are the different causes of variation?

Answer 31

Mutations, genetic recombination and environment

Question 32

What is Analogous structure? provide an example, as well as how it supports evolution

Answer 32

Body parts in different species that have similar function but different structure and origin. e.g. wings of birds and insects Supports evolution as they are not related, they adapted to do the same thing

Question 33

What is Homologous structure? provide an example, as well as explain how it supports evolution

Answer 33

Body parts in different species that have similar structure but different functions. e.g. Pentadactyl limb appearing in many vetebrates Supports evolution as it shows that they adapted the same bone structure from a similar organism

Question 34

What is the function of Cytochrome C?

Answer 34

Cytochrome C is a Ubiquitous protein that helps release the energy we need from food.

Question 35

What is the wallace line?

Answer 35

The Wallace Line is a natural boundary separating Asian and Australian species, caused by deep ocean waters and plate tectonics. It explains why marsupials are found in Australia and nearby islands, but not in mainland Asia.

Question 36

What are the four ways fossilisation can occur?

Answer 36

Petrification Compression Moulds and casts Preserved remains

Question 37

What is comparative embyrology?

Answer 37

Study of the similarities and differences in the embryos of different species. Similarities embryos share, may no longer be present in adulthood.

Question 38

What is comparative anatomy?

Answer 38

The study of similarities and differences in the structures of different species

Question 39

What is the most common body part to be fossilized and why?

Answer 39

Teeth and bones are the most likely, because they are the hardest structures and unlikely to decompose over time

Question 40

What is ionisation? And how do cations and anions form?

Answer 40

ionisation is when an atom or molecule gains or loses electrons to have a charge. Cations lose, positive. Anions gain, negative.

Question 41

What is the difference between a covalent and ionic bond?

Answer 41

Covalent compound - two non metals share electrons to fill their outermost shell. low melting point, weak intramolecular bonds. Ionic compound - metal and non metal bond together, non metal gains, metal loses. High melting point, strong electrostatic forces (intramolecular bonds).

Question 42

Provide an example of geographical distribution

Answer 42

Darwin's Finches on the Galapagos islands

Question 43

Describe the process of Big Bang Nucleosynthesis

Answer 43

When the Universe was in a hot dense state, it eventually expanded and cooled. Protons and neutrons combined to form hydrogen, carbon, lithium.

Question 44

How does metal reactivity change across a period?

Answer 44

Metal reactivity decreases across a period

Question 45

Define biological evolution

Answer 45

The process of changes being inherited within a species over time