Exam Review – Part 2

Exam Review – Part 2
Evolution and Diversity
You Should Know…
1. What does Evolution mean?
2. What evidence does Darwin have to support his Theory of Evolution?
3. What is an adaptation?
4. Explain 3 ‘selective’ mechanisms by which evolution occurs and 3 non
‘selective mechanisms.
– Natural Selection, Artificial Selection and Sexual Selection
– Genetic Variation, Genetic Drift and Genetic Bottleneck
4. Be able to compare and contrast the different Modes of Speciation
– Reproductive Isolation, Allopatric Speciation and Sympatric
5. Be able to compare and contrast the different patterns of Evolution
– Convergent
– Divergent
– Co Evolution
6. Know the different types of Diversity
– Genetic, Species and Ecosystem
7. Know the Kingdoms of Classification
– 6 Kingdoms (Characteristics and Representative Members)
8. Why are Viruses not considered to be alive??
8. What Phyla make up the Animal Kingdom?
– Invertebrates and Vertebrates
9. Know some key characteristics of each of the
invertebrate phyla and each of the classes of
vertebrates we talked about
10. Be able to discuss how organisms in the Animal
Kingdom have become more complex and advanced
and how they are adapted to their environments.
11. Know how to use a dichotomous key
Principle of Science
• Seeks to explain the natural world.
• Assumes that this is possible by gathering
evidence about it.
• Theories are central to scientific thinking:
• Theory
- Popular meaning: a guess
- In science: a well-substantiated
explanation of events observed in the
natural world
– Darwin defined this term as "descent with
• biological evolution is the process of change by which
new species develop from preexisting species over
• Living organisms pass on their traits to their offspring.
• Today’s species came about through gradual change.
• What drove that change?
What Darwin Observed
• 1) Homologous and
Analogous Features
– Homologous features:
different functions,
but similar structure
(flippers, hands,
• Analogous features: similar functions,
but different structure (wings of birds
and bees)
• Darwin’s conclusion: organisms with
homologous features likely shared a
more recent ancestor, while those with
analogous features do not!
2) Vestigial Features:
• non-functional
structures that are
homologous to fully
functioning structures
in closely related
– Example: whales have
pelvic bones that do not
attach to legs
3) Artificial Selection
– Selecting offspring with desirable traits as
breeding stock for succeeding generations
– Example: corn with higher oil content
– Darwin’s conclusion: if people could alter the
appearance and behaviour of species through
artificial selection, then the environment
could have a similar selective effect on wild
4) The Struggle for Survival
– Plants and animals produce more offspring
than are able to survive
– Favourable variations would tend to be
preserved, unfavourable ones would be
Direct observation of species
Bacteria become
resistant to
Wolves were bred over
many generations to
become dogs (artificial
selection) • and then bred
further to create a variety
of breeds
Mechanisms for Evolution
• Natural variation--differences among
individuals of a species
• Artificial selectionnature provides the variation among different
organisms, and humans select those variations
they find useful.
• Sexual Selection:
the process by which a trait that enables an
organism to acquire more mates becomes
more common.
Evolutional Change without
• Not all evolutionary changes are the
result of selection.
• These changes can have a big impact on
a species if the population is small.
1. Genetic Drift
2. Genetic Bottleneck
3. Founder Effect
Gene Flow
• The transfer of
alleles from one
population to
Genetic Drift
changes to the allele frequency of a
population as a result of chance.
Bottleneck Effect
Genetic diversity is lost as a
result of a drastic reduction
in population size.
Alleles are lost
Effect (Type of
Genetic Drift)
•Individuals of a species (founding
population) start a new population
somewhere else.
• A new species is formed when two
populations of plants or animals
accumulate so many genetic changes
(mutations, adaptations) that they
cannot interbreed and produce fertile
But how did these species
There are 4 patterns that the evolutionary
process may follow…
single species
evolves into a number of other species.
1. •A
•A large scaleevolution
evolution of a group of species into many
2. Divergent
different species.
•The evolution of
similar traits in
3. Convergent
distantly related species.
•One species evolves in response to evolution of
another species.
Modes of Speciation…
• These processes all include the
evolution of distinct features that
isolate the new species reproductively
and as a result genetically fro the
prevented from breeding together because
of behavioural, structural or biochemical traits.
1. Reproductive isolation
A new species develops after being geographically
separated from the original population.
2. Allopatric Speciation
New species are formed when individuals within a larger
population become genetically isolated.
What Types of Biodiversity are
• Genetic Diversity –
– variety of inherited characteristics within a
– Species vary in their genetic make up
• Ecosystem Diversity –
– variety of ecosystems on Earth
• Species Diversity –
– variety of species in an ecosystem.
– The greater the number of species in an
ecosystem, the greater the species diversity
The Six Kingdoms
Be able to describe characteristics of each kingdom and give
an example of an organism from each.
1. Eubacteria (Bacteria)
4. Fungi
2. Archaebacteria (Archaea)
5. Plantae
3. Protista
6. Animalia
Eukaryotic cells evolved from
- They contained organelles —
membrane bound compartments with
specialized functions:
• Nucleus
• Chloroplast
• This kingdom contains organisms that
display animal-like, plant-like and fungi-like
Aerobic prokaryotes
benefit from food
Eukaryotes benefit
from energy.
prokaryotes benefit
from carbon dioxide
inside of eukaryotes
and eukaryotes
benefit from extra
food produced by
Three Groups of Protists
• 1. Plant-Like: contain chlorophyll and may
produce food through photosynthesis, …
but not always (some have flagella and no
cell wall)
• 2. Animal-Like (Protozoa): heterotrophs
and are very likely to be parasitic
• 3. Fungi-Like (slime moulds): some
produce spores
Vertebrates/ Invertebrates
Be able to name the 5 phyla of invertebrates and
give an example of each.
You should be able to describe the characteristics
of each class.
Be able to name the 5 classes of vertebrates and
give an example of each.
You should be able to describe the characteristics
of each class.
(5 main phylum)
Phylum Chordata
can be split up into 5 classes.
amphibians birds
fish mammals reptiles
Remember the five classes of phylum Chordata.
Evolution and Diversity
• You should be able to discuss how
organisms in the Animal Kingdom have
become more complex.
• Compare digestive, respiratory and
circulatory systems
• Explain how certain traits or characteristics
may have evolved.