Natual Selection And Genetic Modification Flashcards
What is evolution?
The gradual change in a species characteristics over time
What is Darwin’s theory of natural selection also referred to as?
Survival of the fittest
What is natural selection?
The natural process where the best-adapted individuals survive longer, have more offspring so spread their characteristics
What species was Ardi?
Ardipithecus ramidus
What species was Lucy?
Australopithacus afarensis
What was significant about Mary and Louis Leaky’s discoveries from 1.6 m.y.a?
The skeleton looks much more like a modern human than either Ardi or Lucy. This skeleton suggests that humans may have evolved.
Order these species in how long ago they lived (oldest to current)
- Homo sapiens
- Homo habilis
- Ardipithecus ramidus
- Australopithecus afarensis
- Homo erectus
- Adripithecus ramidus
- Australopithecus afarensis
- Homo habilis
- Homo erectus
- Homo sapiens
How long ago did Adripithecus ramidus live?
4.4 m.y.a
How long ago did Australopithecus afarensis live?
3.2 m.y.a
How long ago did Homo habilis live?
1.6 m.y.a
How long ago did Homo erectus live?
0.8 m.y.a
How long ago did Homo neanderthalensis live?
0.2 m.y.a
What was the first species of human to make stone tools?
Homo habilis
What are fossils?
The imprints or remains of organisms which were alive thousands or millions of years ago
What are the different ways fossils can be formed?
- From the organism’s remains
- From a footprint or imprint (trace fossils)
How are fossils formed?
- Organism dies and is covered in sediment
- Over thousands of years more sediment is deposited on top
- The weight and the pressure causes the deposits to form sedimentary rock
- Minerals replace air spaces in the organism and the parts of the organism left will turn to stone
- Geological activity like earthquakes or mountains being formed will cause the fossils to rise up and become exposed
What evidence is there that humans evolved based on fossils?
Skull volume gets larger as human like species evolved (Ardi had skull volume of 350 cm2 and Homo sapiens have an approximate skull volume of 1450 cm2) and the theory of evolution states that simple life forms will evolve into more complex ones
Why do we not have fossils for every species that lived on Earth?
- Early organisms had soft bodies, which would have decayed
- Many fossils have been destroyed by geologic activity such as volcanoes
- Many fossils still have not been discovered
What evidence is there that humans evolved based on tools?
Stone tools got more advanced over time (more intricately shaped and attached to wood) suggesting a more advanced species and the theory of evolution states that simple life forms will evolve into more complex ones
Who was Alfred Russel Wallace?
Another naturalist who independently proposed the theory of evolution by natural selection before Darwin had released his findings. After this he worked with Darwin, prompting him to publish On The Origin Of Species in 1859
What animal in particular did Darwin study on his voyage?
Finches
How does the pentadactyl limb provide evidence for evolution?
Many vertebrates including humans have the pentadactyl limb, suggesting that they evolved from a common ancestor.
(Then give examples of how different animals evolved and how the pentadactyl limb changed.)
Eg. Bats have evolved a very long and thin pentadactyl limb with skin that has stretched across it to form wings
What is the purpose of antibiotics?
To kill bacteria
How can bacteria become resistant to antibiotics?
- According to Darwin’s theory of natural selection, organisms with better characteristics will survive and spread their characteristics
- Bacteria resistance happens when a person hasn’t finished their course of medication
- When antibiotics are used, all non resistant bacteria is killed
- If any bacteria have survived that mutated to become antibiotic resistant, they will be able to reproduce rapidly and spread to become more common
What is classification?
The grouping of organisms based on similarities of features
What is artificial classification?
Classification based on observable features
What is natural classification?
Classification based on evolutionary links
What are the 7 different taxons of the Linnaean system of classification?
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
What is the binomial system of naming species made up of?
- The genus
- The species
What is a species?
A group of similar organisms able to reproduce and produce fertile offspring
What are the 5 different kingdoms?
- Animal
- Plant
- Fungi
- Protists
- Prokaryotes
Name 4 features of species in the animal kingdom
- Eukaryotic
- Muticellular
- No cell walls
- Must eat other organisms to obtain energy
Name 4 features of species in the plant kingdom
- Eukaryotic
- Multicellular
- Photosynthesise
- Has cellulose cell walls
Name 4 features of species in the fungi kingdom
- Eukaryotic
- Multicellular (apart from yeast)
- Live in/on dead organic matter to feed on to gain energy
- Made up of mycelium and hyphae
- Has chitin cell walls
Name 4 features of species in the protist kingdom
- Eukariotic
- Mostly unicellular
- Some have cell walls
Name 4 features of species in the prokaryote kingdom
- Unicellular
- Prokariotic
- Flexible cell walls
- No membrane bound organelles
What is the name for the classification that groups organisms with similar DNA together?
The three-domain system
What are the three domains in the three-domain system?
- Archaea
- Bacteria
- Eukaryota
Name 3 common features of archea
- Usually live in extreme environments
- No nucleus
- Have unused sections of genes
Name 2 common features of bacteria
- No nucleus
- No unused sections of genes
Name 2 common features of Eukaryota
- Have a nucleus
- Have unused sections of genes
What is selective breeding?
Choosing only organisms with the desired traits to reproduce and act as parents for the next generation
What is genetic engineering?
Changing the structure of a gene usually, to give the organism desired characteristics
What are the advantages of genetic engineering?
- Faster and more efficient that selective breeding
- Can improve crop yields or quality
- Can be used so plants can produce their own pesticides and toxins
What are the disadvantages of genetic engineering?
- GM crop seeds are more expensive
- Insects may develop resistance to the toxin produced
- Ethical issues about interference with nature
Why did the classification system change?
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