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

Speciation5. 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

Evolution– Darwin defined this term as "descent with

modification.”• biological evolution is the process of change by

which new species develop from preexisting species over time

• Living organisms pass on their traits to their offspring.• Today’s species came about through gradual change.• What drove that change?

SURVIVAL/SEX!!!!

What Darwin Observed

• 1) Homologous and Analogous Features

– Homologous features: different functions, but similar structure (flippers, hands, wings)

• 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 species.– 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 species!

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 destroyed.

INTENSE COMPETITION!!!!!

Direct observation of species Direct observation of species change change

Bacteria become Bacteria become resistant to resistant to antibioticsantibiotics

Wolves were bred over Wolves were bred over many generations to many generations to become dogs (become dogs (artificial artificial selectionselection) • and then bred ) • and then bred further to create a variety further to create a variety of breedsof breeds

Mechanisms for Evolution• Natural variationNatural variation--differences among --differences among

individuals of a speciesindividuals of a species

• Artificial selectionArtificial selection- - nature provides the variation among different nature provides the variation among different

organisms, and humans select those variations organisms, and humans select those variations they find usefulthey find useful..

• Sexual SelectionSexual Selection: : the process by which a trait that enables an the process by which a trait that enables an

organism to acquire more mates becomes more organism to acquire more mates becomes more common.common.

Evolutional Change without Selection

• 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 Drift2. Genetic Bottleneck3. Founder Effect

Gene Flow• The transfer of

alleles from one population to another.

Genetic Drift

changes to the allele frequency of a population as a result of chance.

Bottleneck EffectGenetic diversity is lost as a result of a drastic reduction in population size. Alleles are lost Founder Effect (Type of

Genetic Drift)•Individuals of a species (founding population) start a new population somewhere else.

Speciation

• 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 offspring.

But how did these species evolve???

There are 4 patterns that the evolutionary process may follow…

1. Adaptive radiation

2. Divergent evolution

3. Convergent evolution

4. Coevolution

•A single species evolves into a number of other species.

•A large scale evolution of a group of species into many different species.

•The evolution of similar traits in 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 original species.

1. Reproductive isolation

2. Allopatric Speciation

3. Sympatric Speciation

Individuals are prevented from breeding together because of behavioural, structural or biochemical traits.

A new species develops after being geographically separated from the original population.New species are formed when individuals within a larger population become genetically isolated.

What Types of Biodiversity are There?

• Genetic Diversity – – variety of inherited characteristics within a

species– 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 KingdomsBe able to describe characteristics of each kingdom and

give an example of an organism from each.

1. Eubacteria (Bacteria)

2. Archaebacteria (Archaea)

3. Protista

4. Fungi

5. Plantae

6. Animalia

PROKARYOTIC

EUKARYOTIC

Diversity

Eukaryotic cells evolved from prokaryotes.- They contained organelles —membrane bound compartments with specialized functions:

• Nucleus• Chloroplast

Protista

• This kingdom contains organisms that display animal-like, plant-like and fungi-like characteristics.

http://learn.genetics.utah.edu/content/begin/cells/organelles/

Aerobic prokaryotes benefit from food supply.Eukaryotes benefit from energy.

Photosynthetic prokaryotes benefit from carbon dioxide inside of eukaryotes and eukaryotes benefit from extra food produced by prokaryotes.

EVERYONE WINS

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.

Invertebrates(5 main phylum)

molluscsarthropods

Annelida (segmented worms

echinodermscnidarians

jellyfish

8Da

Phylum Chordatacan be split up into 5 classes.

amphibians birds fish mammals reptiles

Remember the five classes of phylum Chordata.

8Da

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.