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Flashcards in Evolution Deck (82):

What is evolution?

When alleles of a species change


Define Selective Breeding

Breeding individuals best for human uses.


What does selective breeding show?

Selective breeding of domesticated animals shows that artificial selection can cause evolution.

Modern breeds of livestock often much different from wild species they most resemble.

Artificial selection effectiveness shown by considerable changes that have occurred in domesticated animals over very short periods of time (compared to geological time)

Shows that selection can cause evolution, but it doesn't prove that evolution of species has actually occurred naturally, or that the mechanism for evolution is natural selection.


Define convergent evolution

Process whereby organisms not closely related independently evolve similar traits as a result of having to adapt to similar environments.


What are rudimentary/vestigial organs and give 2 examples in animals

Reduced structures that serve no function.

Appendix in humans

Beginnings of teeth found in embryo baleen whales.


What are the 4 bone structures of pentadactyl limbs?

Single gone in proximal part

2 bones in distal part

Group of wrist/ankle bones

Series of bones in each of 5 digits


What structures exist in the pentadactyl forelimbs?


Radius and ulna


Metacarpals and phalanges


What structures exist in pentadactyl hindlimbs


Tibia and Fibula


Metatarsals and phalanges


Compare the bone structure, forelimbs and hind limbs in pentadactyl limbs

Bone structure:

Single bone in proximal part
2 bones in distal part
Group of wrist/ankle bones
Series of bones in each of 5 digits


Radius and ulna/tibia and fibula
Metacarpals and phalanges/metatarsals and phalanges.


How do modifications in pattern of bones occur in mammals?

Depends on function of their limbs

- Crocodiles walk or crawl on land and use webbed hindlimbs for swimming
- penguins use hindlimbs for walking and use both hindlimbs and forelimbs for digging
- Frogs use all 4 limbs for walking and their hindlimbs for jumping


When does speciation often occur?

Speciation often occurs after a population of species extends its range by migrating to an island.


Define endemic species

Endemic species is one that is only found in a certain geographical area.


Why is it difficult to classify something as an individual species?

Because species can gradually diverge over long periods of time;

There is no sudden switch from being 2 populations of 1 species to being 2 separate species.


Define adaptations

Characteristics that make an individual suitable to its environment and way of life.


Difference between adaptations and acquired characteristics

Adaptations are characteristics that make an individual suitable to its environment and way of life.

Acquired characteristics occur during lifetime of an individual.

Adaptations can be passed on to offspring of species that reproduce, whilst acquired characteristics cannot.


What is considered to be a characteristic of the members of a Genus.



Which factors could be important for a species to evolve by natural selection?

I. Environmental change
II. Inbreeding
III. Variation

A. I
B. I and II
C. I and III
D. I, II and III



What is natural selection?

A. Making a random choice of partner for reproduction.
B. Increased reproductive success by those with favourable variation.
C. Variation due to mutations in a population.
D. The survival of the largest organisms in a population.



What is the sequence of the seven levels of hierarchy of taxa used in classification?

A. Phylum, kingdom, class, order, family, genus and species
B. Kingdom, family, phylum, class, order, genus and species
C. Kingdom, phylum, class, family, order, species and genus
D. Kingdom, phylum, class, order, family, genus and species



Why has evolution resulted in antibiotic resistance in bacteria?

A. Not completing a course of antibiotics allows resistant bacteria to develop.
B. Bacteria resistant to the antibiotic survive to pass on this characteristic to their offspring.
C. Bacteria change their metabolism to cope with the presence of antibiotics.
D. Bacteria have learnt how to neutralise the effects of the antibiotic and they pass this onto their offspring



Which factors can limit population growth?

I. Shortage of food
II. Increased genetic variation in the population.
III. Increase in predators
IV. Increase in diseases and parasites

A. I and II
B. I and III
C. I, III and IV
D. I, II, III and IV



What are Allium sativa and Allium cepa?

A. Two different species of the same genus
B. The same species of the same genus
C. The same species but of a different genus
D. Two different species of a different genus



The binomial name for white clover is Trifolium repens. Which species name indicates the closest relationship with white clover?

A. Tetrafolium persimilis
B. Trifolium bulbosus
C. Bifolium repens
D. Unifolium trifolians



What structures are used in the locomotion of bony fishes and birds, but not in the locomotion of earthworms and arthropods?

A. Antagonistic muscles
B. Bones to which antagonistic muscles are attached
C. Neurons to stimulate muscle contraction
D. Fins or wings for swimming or flying



Which of the following factors influence carrying capacity?

I. Size of habitat
II. Increase in predators
III. Increase in diseases and parasites

A. I only
B. II only
C. II and III only
D. I, II and III



What is the mechanism of natural selection?

A. Any individuals in a population can be selected entirely by chance.
B. After a change in the environment a species will evolve adaptations to the new conditions.
C. If an adaptation to the environment is useful, an individual will develop it and pass it on to its offspring.
D. Variations amongst individuals of a population are selected by a changing environment.



Which of the organisms A–D, identified by the key below, represents an Annelid?

1. Shows bilateral symmetry (go to 2)
Does not show bilateral symmetry (Cnidaria)

2. Has a segmented body (go to 3)
Does not have a segmented body (go to 4)

3. Has jointed legs (A)
Does not have jointed legs (B)

4. Has a shell (C)
Does not have a shell (D)



Charles Darwin used domesticated animals to provide evidence for evolution by natural selection. What is this evidence?

A. Differences between breeds show that selection can cause species to change.
B. The ancestors of domesticated animals can be found in the fossil record.
C. Some domesticated animals die because the environment cannot support them all.
D. Variation in domesticated animals is due to sexual reproduction.



Pseudolarix amabilis produces seeds but not flowers. Physcomitrella patens has leaves but not roots. To which groups do they belong? (Not in question but answers are in order of Pseudolarix amabilis, then Physcomitrella patens respectively)

A. coniferophyta,
B. filicinophyta,
C. coniferophyta,
D. angiospermophyta,



An animal has radial symmetry, a sac-like body with only one opening and tentacles with stinging structures. To which phylum does this animal belong?

A. Annelida
B. Cnidaria
C. Mollusca
D. Porifera



Which of the following are used as evidence for evolution?

I. Homologous structures
II. Selective breeding of domesticated animals
III. Overproduction of offspring

A. I and II only
B. I and III only
C. II and III only
D. I, II and III



Which phylum does the plant below belong to?

A. Angiospermophyta
B. Bryophyta
C. Coniferophyta
D. Filicinophyta



Which of the following is a characteristic of platyhelminthes?

A. Many pairs of legs
B. Flat body
C. Hard exoskeleton
D. Presence of cnidocytes



Why has antibiotic resistance evolved in bacteria?

A. All bacteria reproduce very quickly.
B. Bacteria exposed to antibiotics developed a resistance to them.
C. Varieties of bacteria resistant to antibiotics reproduce faster than non-resistant varieties.
D. Bacteria showing resistance to antibiotics survive after antibiotics are used.



Which taxa do Zerynthia rumina and Zerynthia polyxena share?

A. They share the same class but not the same family.
B. They share the same species but not the same class.
C. They share the same class but not the same genus.
D. They share the same family but not the same species.



What features distinguish Platyhelminthes from Annelida? (not in question but answers are in order of Platyhelminthes and Annelida respectively).

A. segmented body,
non-segmented body
B. non-segmented body,
segmented body
C. bilateral symmetry,
no bilateral symmetry
D. no bilateral symmetry,
bilateral symmetry



The population of white-tailed deer in Nova Scotia (Canada) suffered a significant decline in the late 1970s. Which of the following is most likely to have caused the decline?

A. The population had depleted resources in the environment
B. A decrease in hunting
C. A decrease in predation
D. Natality and immigration exceeded mortality and emigration



Two different trees have been classified as Pinus pinea and Pinus nigra. Which of the following statements is correct?

A. Both trees belong to the same class but a different genus.
B. Both trees belong to the same family and same genus.
C. The species name of both trees is Pinus.
D. The family names are pinea and nigra.



A collection of four animal specimens is observed and a dichotomous key is applied. Which specimen is an arthropod?

1. Non-segmented body ................. go to 2 Segmented body ............................. go to 3

2. Body is not symmetrical ... specimen A Body is symmetrical ............... specimen B

3. Jointed appendages present ............ specimen C
Jointed appendages absent .............. specimen D

A. Specimen A
B. Specimen B
C. Specimen C
D. Specimen D



Which of the following represent homologous features?

A. Wings in birds and insects
B. The appendix in humans and horses
C. Fins in fish and wings in birds
D. The striped coat of the zebra and the tiger



The following diagrams (not to scale) represent the fossilized forelimbs of three horses living at different times, none of which are alive today.

The diagrams provide evidence for which of the following?

A. Pentadactyl limb
B. Domestication of animals
C. Homologous structures
D. Change in the characteristics of species



Which organisms have flowers?

A. Bryophyta
B. Porifera
C. Angiospermophyta
D. Cnidaria



Based on binomial nomenclature, which two species are most closely related?

I. Common barberry (Berberis vulgaris)
II. Canadian bunchberry (Cornus canadensis)
III. Smooth blackberry (Rubus canadensis)
IV. Canadian barberry (Berberis canadensis)

A. I and IV
B. II and III
C. II and IV
D. III and IV



What causes variation in both sexually and asexually reproducing organisms?

A. Mutations
B. Polygenic inheritance
C. Crossing over
D. Independent assortment



What type of process causes antibiotic resistance to develop in bacteria?

A. Competition with viruses
B. Overproduction of offspring
C. Evolution due to environmental change
D. Response by bacteria to an epidemic



A biologist exploring an uninhabited island came across an unknown plant. She made the following notes:

• grows in a damp and shady corner of the island
• has large feathery leaves with spore cases (sporangia) arranged on the underside
• young leaves are tightly rolled up
• has roots.
In what phylum should she classify this plant?

A. Angiospermophyta
B. Bryophyta
C. Coniferophyta
D. Filicinophyta



Ranunculus repens and Hypericum repens both have yellow flowers. Which statement is true?

A. They are angiospermophytes.
B. They are coniferophytes.
C. They are members of the same species.
D. They are members of the same genus.



What distinguishes Annelida from Platyhelminthes?

A. Platyhelminthes have a segmented body but Annelida do not.
B. Platyhelminthes reproduce sexually but Annelida do not.
C. Platyhelminthes have radial symmetry but Annelida have bilateral symmetry.
D. Annelida have both a mouth and an anus but Platyhelminthes do not.



What features occur in all species of Angiospermophyta and Coniferophyta?

A. Seeds
B. Bark
C. Cones
D. Flowers



What is the phylum of a plant that has roots, short non-woody stems, leaves often curled up in bud and dispersal is by spores not seeds?

A. Angiospermophyta
B. Bryophyta
C. Coniferophyta
D. Filicinophyta



What is accepted by scientists as evidence for evolution?

I. Similarities in bone structure between the wings of a bat and the fins of a porpoise
II. Changes in dog breeds caused by artificial selection
III. Extinction of dinosaurs

A. I only
B. I and II only
C. I and III only
D. I, II and III



Which images show cnidaria?

A. I and II only
B. I and III only
C. II and IV only
D. III and IV only



Which sequence of taxonomic groups goes from largest to smallest?

A. phylum, order, class, species, genus
B. kingdom, family, class,
genus, species
C. phylum, class, order, family, species
D. kingdom, phylum, family, order, genus



What is essential for natural selection to occur?

A. Variation between members of a species
B. Large population size
C. High mortality rate
D. Environmental catastrophe



In classification, which statement is true?

A. If two organisms belong to the same order, then they are in the same genus.
B. If two organisms are in different orders, then they cannot be in the same class.
C. If two organisms are in the same class, then they must be in the same phylum.
D. If organisms have the same genus name, they must also have the same species name.



On sites polluted with heavy metals, some grasses show tolerance to concentrations of those metals that are normally toxic. What explains this tolerance?

A. Grasses continually exposed to high doses of heavy metals mutate.
B. Rapid reproduction rate of grasses produces little genetic variation.
C. Grasses not killed by the heavy metals reproduce and pass on their genes.
D. Heavy metals become less toxic over time.



What is the phylum of the organism?

A. Porifera
B. Cnidaria
C. Platyhelminthes
D. Annelida



Antibiotic resistance in bacteria is an example of evolution in response to environmental change. Using another example, explain how an environmental change can lead to evolution.

Natural selection is the process whereby organisms better adapted to their environment tend to survive and produce more offspring than those that are not adapted;
and it can lead to evolution; which is the cumulative change in the heritable characteristics of a population;

Peppered Moths are a species of moths that have two varieties: light and peppered or a dark melanic colour is present;
Pollution from industrial activities caused trees to blacken with soot;
light coloured moths died from predation, whereas melanic moths were camouflaged and survived to pass on their genes;
frequency of melanic colour allele in population increased


Outline the use of the binomial system of nomenclature in Campanula persicifolia.

Campanula is the genus name and persicifolia is the species name;

all members of Campanula persicifolia share unique features;

two names make a unique combination to designate species.


There are many animals living on Earth today that belong to the same phylum as the trilobites, but there are no living trilobites. Deduce, with a reason, the phylum to which Triarthus belonged.

arthropoda/arthropods; because of jointed legs/limbs/appendages


Outline the evidence for evolution provided by fossils.

fossils show changes over time (in organisms);
fossilized organisms are different from existing ones;
yet share homologous structures with existing organisms; which suggests common ancestry;

they also show intermediate stages in evolution of groups;


Some trilobites swam in clear, shallow water and had very large eyes. Suggest how species with large eyes could evolve from species with smaller eyes.

natural selection; over time; increases variation in size of eye;

individuals with larger eyes are more likely to survive; and reproduce (and pass on their genes to offspring).


Describe the consequences of overpopulation of a species.

members of a species tend to produce more offspring than can survive;
competition for available resources occurs;
habitat has a carrying capacity;
overpopulation is when carrying capacity is exceeded;

food web may be interrupted;
invasion of new habitats by the overpopulating species;
natural selection of successful variations;
evolution of a species with new characteristics;
mortality will exceed natality, causing population numbers to drop back to below carrying capacity;


State an external feature that is different in:

(i) Cnidaria and Mollusca

(ii) Mollusca and Annelida

(i) Cnidaria have radial symmetry while Mollusca have bilateral symmetry;

(ii) Annelida are segmented while Mollusca are not;


Outline the types of evidence that can be used to support the theory of evolution.

fossils give evidence of evolution; because they show different species existed in the past/species changed over time;

selective breeding of domesticated animals; shows that (artificial) selection can cause rapid change;

base sequences show species diverged;


The probability of extinction of a species increases if the population is small with low genetic variation.

State two processes that cause population size to decrease.

mortality; emigration;


Explain how meiosis promotes variation.

Crossing over between homologous chromosomes in prophase I greatly increases number of potential gamete variations by creating new genetic combinations;

Independent assortment of chromosomes in anaphase I creates 2^n different gamete combinations (n = haploid number of chromosomes);
(there's a mark hidden so this answer is 3 marks)


1. a. The beak is relatively long and slender ...... Certhidea
b. The beak is relatively stout and heavy ............. go to 2

2. a. The bottom surface of the lower beak is flat and straight .......................................................................... Geospiza
b. The bottom surface of the lower beak is curved ............................................................................................. go to 3

3. a. The lower edge of the upper beak has a distinct bend .................................................................. Camarthynchus
b. The lower edge of the upper beak is mostly flat ........................................................................................ Platyspiza

(a) Using the dichotomous key above, identify the genus of bird W and Z

(b) Identify, with a reason, which bird could best eat insects that live in small cracks in trees.

(a) Bird W is Geospiza

Bird Z is Camarhynchus

(b) Bird Y has a more slender beak to pick out insects from cracks.


The environment where these four birds live has changed and there are now fewer trees producing nuts and fruit but more insects available for food. Describe how natural selection in this situation could lead to evolution.

birds show variation in their beaks;
birds that find food are more likely to survive and reproduce; producing offspring and passing on their genes to offspring;
this leads to an increase in population of one species and decrease in the others;


In a given population some variations of a protein are expressed more frequently than others. Outline how evolution through natural selection can lead to the expression of one version of a protein rather than another.

a. different alleles for proteins exist in nature;

b. a change in external environment (eg: use of antibiotic); causes organisms expressing one allele/protein have advantage over those expressing

c. organisms expressing one protein have greater chances of survival; and so can reproduce more; to produce more offspring who inherit the expression of given protein;

d. population expressing the given protein increases (while the ones expressing the other protein decreases); and after a few generations, the characteristic of the species gradually changes;


Outline the role of variation in evolution.

members of a population show variation;

variation between members of a population comes from sexual reproduction, meiosis and mutation;

some variations allow an individual to be better adapted;

better adapted varieties survive to reproductive age (whereas less adapted varieties die or produce less offspring);

frequency of advantageous alleles therefore increases over time.


Outline how antibiotic resistance in bacteria can arise in response to environmental change.

antibiotic resistance can be inherited; as alleles for resistance can be passed from one cell to another by conjugation;

bacteria reproduce very rapidly and have a high mutation rate; so evolution can occur rapidly;

increased exposure to antibiotics is an environmental change that selects for resistant varieties; (such as through inappropriate prescriptions);

resistant bacteria survive and pass on genes to next generation / (bacteria without resistance die);

results in change in genetic makeup of population;


Explain two examples of evolution in response to an environmental change.

Staphylococcus aureus is a species of bacteria; introduction of methicillin (an antibiotic) to kill this bacteria caused a mutation to occur;
some bacteria were resistant (MRSA) and others were not (MSSA);
MRSA survived, multiplied and passed on their genes, whilst MSSA died; frequency of antibiotic resistance allele in population increased over time;

Peppered Moths are a species of moths that have two varieties: light and peppered or a dark melanic colour is present;
Pollution from industrial activities caused trees to blacken with soot;
light coloured moths died from predation, whereas melanic moths were camouflaged and survived to pass on their genes;
frequency of melanic colour allele in population increased


Define analogous structures

Structures with different origins, but have become similar because they perform same or similar function.


Define divergent evolution

Process by which a species diverges into two or more descendent species,


Define homologous structures

Parts of a species that are similar in structure to other species' comparative parts.


Classify one plant species

Date Palm



Define clade

Group of organisms that have evolved from a common ancestor


What is a molecular clock and why is it used?

Sequence differences accumulate gradually over time, so there is a positive correlation between number of differences between 2 species and time since they diverged from a common ancestor

Differences in base sequence of DNA caused by mutations which occur at a roughly constant rate so they can be used as a molecular clock.

Number of differences in sequence can be used to deduce how long ago a species split from common ancestor.


Define a cladogram

Tree diagram that shows most probable sequence of divergence in clashes; based on similarities and differences between species in a clade


What are nodes in a cladogram?

Branching points; they represent hypothetical ancestral species that split to form 2 or more species


Give an example of how a clade was reclassified

The Figwort family was the 8th largest angiospermophyte family;
Originally included 16 genera based on similarities in morphology;
As more plants discovered, family grew to >300 genera and >5000 species;
Base sequences of 3 chloroplast genes in large number of genera traditionally assigned to figwort family and genera in closely related families;
Species in figwort family not true clade and that 5 clades had been combined to 1 family;
Now only 36th largest angiospermophyte family