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EVOLUTION & BIODIVERSITY
TOPIC 5
5.1 – EVIDENCE FOR EVOLUTION .................. 1 5.2 – NATURAL SELECTION ............................. 7 5.3 – CLASSIFICATION FOR BIODIVERSITY . 12 5.4 – CLADISTICS ............................................ 13
SAMPLE QUESTIONS ..................................... 18
TOPIC 5 – EVOLUTION & BIODIVERSITY
1
5.1 – EVIDENCE FOR EVOLUTION
EVOLUTION
•
• The changes are _________________ and _________________ over _________________ _________________
• The changes occur in _________________ controlled by _________________ • The changes occur at a _________________ _________________
• The evidence for evolution is strong, but it is still considered to be just a theory.
• The theory of evolution has stood up to repeated research, testing and evidence collection. • The theory gets _____________________ as new data emerges. • • Some examples of evidence for evolution:
− __________________________________________ − _____________________ _____________________ − _____________________ _____________________
− Also __________________________________________,
__________________________________________, __________________________________________
2
THE FOSSIL RECORD
• ______________________________________
of plants, animals and prokaryotes are able to be _____________________ in _____________________ of _____________________________________.
• The _____________________ the fossils are found, the _____________________ they are.
• The fossils could show a _____________________ over time as a species develops.
• Transitional species have been uncovered. • eg. ___________________________________
is a transitional fossil between _____________________ and ____________________________________
• Fossils are
• The ____________ of all _____________________ and
_____________________ _____________________ and their _____________________ _____________________ in ____________________ forms the fossil record.
• The fossil record tries to create a _____________________ to the study of fossils and evolution.
• There are _____________________ in the fossil record: − because ____________________________________________________________ − because ____________________________________________________________ − because ____________________________________________________________
• Transitional species show the links between groups and species by traits/features common to the _____________________ species and the theorised _____________________.
• eg. Archeopteryx lithographica has a combination of avian and reptilian features.
3
SELECTIVE BREEDING
HOMOLOGOUS STRUCTURES
• Also called __________________________________________ • The process by which humans breed organisms for _______________________________.
• eg. breeding dogs for racing or herding • eg. _____________________ bred for yielding milk or meat • eg. breeding crops for increased yield or ________________________________________
• Comparing the _____________________ of groups of organisms uncovers some structural
features that are _____________________. • These structures are referred to as __________________________________________. • These similarities imply _____________________ _____________________ between the
organisms. • If these homologous structures are used in different ways by the different species, it implies
_____________________ _____________________ into different ___________________.
• eg. the _____________________________________ in _____________________
4
HOMOLOGOUS STRUCTURES
Looking for trends and discrepancies • There are common features in the bone structure of vertebrate
limbs despite their varied use.
• The five-fingered limb was adapted by modification for different uses/habitats:
− Mammals for __________________________________________________________ − Birds for _____________________________________________________________ − Amphibians for ________________________________________________________ − Reptiles for ___________________________________________________________
5
DIVERGENT EVOLUTION
• _____________________ of a species can ______________________________________
into _____________________ _____________________ by evolution.
• If populations are _____________________, and therefore _____________________ _____________________ from one another, it is likely that they will experience _____________________ _____________________.
• Over many generations, the population will change as a result of _____________________ _____________________ (Topic 5.2).
• If the _____________________ continues to be _____________________ for a long period of time, the separated populations will not be able to _____________ with each other even when they are _____________________. This is called _____________________.
• Populations can become reproductively isolated from one another by a ________________ of some description.
• The barrier could be: − _____________________ – separated by a river or mountain range − _____________________ – around at different times − _____________________ – different mating rituals or calls − _____________________ – prefer different food/plants − _____________________ – aspects of environment favour one form over another
• Speciation can be _____________________ or _____________________. • _____________________ _____________________ used the _____________________
of the _____________________ _____________________ as an example of speciation occurring in this way.
6
CONTINUOUS VARIATION
THE PEPPERED MOTH
• Continuous variation of _____________________ populations
can exist across a __________________________________ • This matches the concept of _____________________
_____________________.
• eg. _____________________ gulls are an example of a _____________________ showing continuous variation where _____________________ is able to occur
• The gulls _____________________ in a ring around the ________________.
• ie. Species 1 can breed with Species 2, Species 2 can breed with Species_____________________, etc
• However, Species 1 (Lesser black-backed gull - L. fuscus) is sufficiently different from _____________________ (European herring gull - L. argentatus). These two species __________________________________________.
• Up until mid 19th century, most peppered moths were
__________________________________________, but ______________________________________ did exist.
• Their light colour allowed them to _____________________ against _________________________________________ on the trees and rocks.
• _____________________ produced ________________ and _____________________. This soot covered the trees and killed then lichen.
• The black mutant was now able to camouflage against the soot-covered trees. Its population _____________________, while the population of white moths decreases due to _____________________ by birds.
• NOTE: _____________________ _____________________ in Europe have ______________________________________________________________ and evolution of the peppered moth is now _____________________!
• Complete relevant practice Qs beginning on Page 18.
7
5.2 – NATURAL SELECTION
This causes a struggle for survival.
Finding, catching
Shelter, nesting sites
Attracting, fertilising
Catching, avoiding
Avoiding, tolerating
Resulting from…
8
• _____________________ are _____________________ that make an individual _____________________ its _____________________ and way of life.
• Variations that give an advantage are selected for:
− The individual which can _____________________ best in the __________________________________________ will survive long enough to _____________________ – and _____________________ the trait.
− _____________________ of these _____________________ will _____________________ and _____________________, the population will _____________________.
• Variations that give a disadvantage are selected against:
− The individual is _____________________ to the environment, making it more _____________________ for them to survive. The individual is __________________ to pass on the trait.
− Frequency of these genes will _____________________.
• Process of natural selection: 1. ________________________ of offspring OR environmental change 2. _____________________ exists in a population 3. _____________________ for survival (due to
__________________________________________) 4. Advantageous variations are _____________________ 5. _____________________ to reproduce and pass on genes 6. Gene frequency increases and _____________________ becomes more common in
population
• Only changes in the _____________________ characteristics of a population can be passed on.
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EXAMPLES OF EVOLUTION • Some species have a __________________________________________ and
__________________________________________ can be _____________________ _____________________.
• Most species have a _____________________ generation time and the evolutionary changes are _____________________ – so there is only _____________________ evidence for evolution.
• Examples of evolution: − _______________________________________________________________ − _______________________________________________________________ − _______________________________________________________________
Theories can be used to explain natural phenomena • The theory of evolution by natural selection can explain the
development of antibiotic resistance in bacteria.
Antibiotic resistant bacteria:
• Most individuals in a bacterial colony are __________________________________________.
• Mutations give rise to _____________________. • Some of these variations will
result in _____________________ to certain _____________________.
• The resistant strain will _____________________. • ______________________________________ are passed
on and the resistant population grows. • eg. Staphyloccoccus aureus bacteria
(_____________________________) is usually treated with _____________________. • There is now a methycillin-resistant strain of Golden Staph (_____________________). • This is could cause big problems in the future, as bacteria could become resistant to
_____________________ antibiotics. • Could create a colony of “_____________________”! • Worried? Go study _____________________ and research new antibiotics!!!!!
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EXAMPLES OF EVOLUTION
1
Darwin’s finches: • The Galapagos Islands are a group of _____________________ islands, off the coast of
_____________________. • _________________ visited the islands in ________ on _____________________.
• The finches evolved from a _____________________ _____________________ of finches on the mainland.
• Darwin believed that they might have been _____________________ course to their new habitats by a _____________________.
• Each habitat had ___________________________________________________________, so _____________________ (_____________________ of years!), the finches _____________________ to suit their own islands.
• They eventually became __________________________________________. • This is __________________________________________.
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EXAMPLES OF EVOLUTION
2
• The Island of _____________________ _____________________ is a small, isolated island
susceptible to __________________________________________. • There are two species of finches that have been studies for years on this island:
− _____________________ ground finch − _____________________ ground finch – original species on the island
• Large ground finch:
− Beak is large, ideal for _____________________________. − A _____________________ (1974-1977 La Niña event) resulted in a
_____________________ of _____________________ seeds − Consequence was a _____________________ in the _____________________ of
finches − The mean beak size of _____________________ finches was ________________. − The mean beak size of successive generations ____________________________.
• Medium ground finch:
− Beak is short and thick, ideal for small and medium seeds. − _______________________________________________________________ (1983
El Niño event) resulted in an _____________________ of smaller sized seeds − Consequence was a _____________________ in the mean beak size of successive
generations.
• https://www.youtube.com/watch?v=OOeb7f9NTUo
• Complete relevant practice Qs beginning on Page 20.
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5.3 – CLASSIFICATION FOR BIODIVERSITY
U – 1. The binomial system of names for species is universal among biologists and has been
agreed and developed at a series of congresses. 2. When species are discovered they are given scientific names using the binomial system. 3. Taxonomists classify species using a hierarchy of taxa. 4. All organisms are classified into three domains. 5. The principal taxa for classifying eukaryotes are kingdom, phylum, class, order, family,
genus and species. 6. In a natural classification, the genus and accompanying higher taxa consist of all the
species that have evolved from one common ancestral species. 7. Taxonomists sometimes reclassify groups of species when new evidence shows that a
previous taxon contains species that have evolved from different ancestral species. 8. Natural classifications help in identification of species and allow the prediction of
characteristics shared by species within a group.
A – 1. Classification of one plant and one animal species from domain to species level. 2. Recognition features of bryophyta, filicinophyta, coniferophyta and angiospermophyta. 3. Recognition features of porifera, cnidaria, platylhelmintha, annelida, mollusca, arthropoda
and chordata. 4. Recognition of features of birds, mammals, amphibians, reptiles and fish.
S – 1. Construction of dichotomous keys for use in identifying specimens. NOS 4.3 - Cooperation and collaboration between groups of scientists—scientists use the binomial system to identify a species rather than the many different local names. • Complete relevant practice Qs beginning on Page 22.
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5.4 – CLADISTICS
CLADOGRAMS
1
• Cladograms are _____________________________
that show the similarities and differences between different species.
• _____________________ points on cladograms are called _____________________.
• Nodes indicate a _____________________________ between the remaining organisms with shared derived characteristics
• Cladograms are mostly based on _____________________
_____________________ or _____________________ _____________________ in a protein.
• Clade:
• Clades can be small or large • Some members of a clade may be _____________________
• The _____________________________ used to build a cladogram can also be used to
estimate _____________________ species diverged from one another. • _____________________ in DNA that are _____________________ occur at a
“__________________________________________”. • This rate can be used as a __________________________________________ to calculate
how long ago a species diverged. • The _____________________ _____________________, the more
_____________________ they shared _________________________________________.
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CLADOGRAMS
2
Primate cladogram:
1 What animal is most closely related to humans?
2 What animals are more closely related to humans than old world monkeys? 3 Which animal diverged from the primate ancestor first?
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HOMOLOGOUS & ANALOGOUS TRAITS
• Traits can be homologous and analogous.
ANALOGOUS HOMOLOGOUS
Structurally _____________________ Structurally _____________________
Functionally _____________________ Functionally _____________________
_____________________ evolution _____________________ evolution
Examples
Examples
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THE FIGWORT FAMILY
Falsification of theories with one theory being superseded by another • Plant families have been reclassified as a result of evidence from
cladistics.
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THE FIGWORT FAMILY
• Evidence from cladistics has shown that classifications of some groups based on
_____________________ did not _____________________ with the _____________________ _____________________ of a group or species.
• eg. _____________________ or _____________________ family
• DNA evidence identified ______________________________________________________ • The members of the family were _____________________ as a result
• Most Figworts have been reclassified into the closely related Plantain, Lopseed, and
Broomrape families. • Now all of these families are ______________________________ to
_____________________, and the remaining genera in the Figwort family lack strong structural _____________________ between them.
• Complete relevant practice Qs beginning on Page 23.
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SAMPLE QUESTIONS
EVIDENCE FOR EVOLUTION
1
Q1 Divergent evolution is often seen among species on different islands because:
A. island populations are usually smaller and more affected by genetic drift. B. natural selection does not occur on islands. C. when islands are first colonised, many ecological resources are unused, allowing
descendants of a colonising species to diversify so descendants have the adaptations that enable them to survive in many different parts of the environment.
D. island species experience identical conditions on each of their respective islands Q2 New species arise from a common ancestor when
A. populations of the ancestral species become geographically isolated from one another. B. populations of the ancestral species become reproductively isolated from one another. C. both A and B. D. neither A or B.
Q3 Fossils are the preserved remains or traces of animals, plants and other organisms from
the past. Organisms are only rarely preserved as fossils, and only a fraction of these fossils have been discovered. The number of species known through the fossil record is less than 5% of the number of known living species. A condition that would favour the fossilisation of an organism is
A. possession of soft body parts which are easily compressed under sediment. B. possession of hard body parts. C. slow burial, which reduces damage to remains. D. an environment with strong winds or water current.
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EVIDENCE FOR EVOLUTION
2
Q4 Outline the evidence for evolution provided by homologous structures. [6]
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NATURAL SELECTION
1
Q1 Charles Darwin and Alfred Wallace proposed a theory of evolution in the late 1850s. One observation made by Darwin that helped formulate the theory was:
A. the environment remaining constant during the lifetime of an organism. B. individual organisms losing a trait that was not in use. C. individual organisms evolving in their own lifetime. D. inherited variation existing within a population
Q2 Since the introduction of the poisonous cane toad to Australia in 1935, there has been an
increase in the ratio of body length to head size in two species of snakes, the Red-bellied Black Snake and the Green Tree Snake. A smaller headed snake cannot consume a large prey item, and so cannot swallow a large cane toad that has sufficient toxin to kill the snake. The rapid evolution of body dimensions in the Red-bellied Black Snake and the Green Tree Snake most likely came about because
A. cane toad toxin reduced the head size of the snakes. B. even small cane toads contain enough toxin to kill a long-bodied snake. C. smaller headed snakes are better at catching cane toads than large headed snakes. D. larger headed snakes were killed by the levels of toxin ingested when they ate a large
cane toad Q3 Explain how natural selection can lead to evolution using antibiotic resistance in bacteria as
an example. [9]
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NATURAL SELECTION
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CLASSIFICATION
Q1 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.
Q2 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.
Q3 State an external feature that is different in:
c. Cnidaria and Mollusca. [1] ......................................................................................................................................
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d. Mollusca and Annelida. [1] ......................................................................................................................................
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Q4
a. Define the term species. [2] ......................................................................................................................................
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b. List three domains into which living organisms are classified. [1] ......................................................................................................................................
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c. There are seven levels used in the hierarchy of taxa. State which two are used in the binomial system of nomenclature. [1]
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CLADISTICS
1
Q1
a. Outline the evidence provided by DNA for the common ancestry of living organisms. [2]
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b. The cladogram below shows the classification of species A to D. Deduce how similar
species A is to species B, C and D. [2]
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c. Suggest two reasons for using cladograms for the classification of organisms. [2]
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CLADISTICS
2
Q2 It has been suggested that elephant-like ancestors of the woolly mammoth left Africa 3.5
million years ago (mya) and lived in Central Europe. The chart below shows a summarised phylogenetic tree based on mitochondrial and chromosomal DNA from fossils and living elephants.
a. Explain how the woolly mammoth M. primigenius probably arose from the woolly mammoth ancestor M. africanavus. [3]
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b. Suggest how it could be possible for M. primigenius to have arisen so recently (0.2 mya) yet now be extinct, while the Asiatic elephant, E. maximus, has been present for over 6 million years. [2]
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