B15 Genetics and Evolution

Question 1

Variation

Answer 1

The difference between members of a species

Question 2

Intra specific variation

Inter specific variation

Answer 2

Same species

In other species (new one they have become)

Question 3

When are 2 new species formed

Answer 3

If they become so different that they can no longer interbreed and produce to form fertile offspring.

Question 4

Evolution

Answer 4

Change in the inherited characteristics of a population overtime (through the process of natural selection, which could lead to a new species)

Question 5

What did Darwin make a lot of observations about

Answer 5

Variation and Evolution

Question 6

Name process of natural selection

Answer 6

• Each species shows variation
• There is competition within each species for food, living space, mates, water
• The “better adapted” members of these species are most likely to survive (“survival of the fitess”)
• These survivors will pass on their better genes to their offspring, who will also show this benefical variation

Question 7

Key points on mutation

Answer 7

It occurs continuously, very rarely can it lead to a new phenotype. If the new phenotype is suited to the environmental change it couldlead to a relatively rapid change in the species

Question 8

Give 2 examples of natural selection

Answer 8

Peppered moth (from plain dark to peppered colour match suroundings)

Rock pokect mouse (grey to black fur)

Question 9

Give 2 examples of evolution

Answer 9

Giraffes (longer necks)

Antibiotic resistant bacteria

Question 10

Explain the process of antibiotic resistant bacteria

Answer 10

• Bacteria can evolve quickly as they reproduce at a rapid rate
• Mutations of bacteria pathogens produce new strains
• Some of which are resistant to antibiotics and so not killed
• They survive and go one to reproduce through natural selection (the population of the resistant strain)
• Could then spread as people not immune (and no effective treatment)

Question 11

Give an example of an antibiotic resistant bacteria

Answer 11

MRSA

Question 12

What can be done to reduce the rate of development of antibiotic resistant strains being produced?

Answer 12

Doctors don’t prescribe antibiotics in appropriately
Patients use the correct antibiotics prescribed
Patients complete each course of antibiotics

Question 13

What’s the problem with developing new antibiotics for these new strains of antibiotic resistant bacteria

Answer 13

Costly and slow

Unlikely to keep up with continuous new resistant strains

Question 14

Extinction

Answer 14

Occurs when there are no remaining individuals of a species still alive

Question 15

New species arise as a result of…

Answer 15

• Environmental variation
• Genetic variation
• Isolation
• Natural selection

Question 16

Speciation

Answer 16

Where the populations becomes so different that successful interbreeding is no longer possible

Question 17

Jean-Baptiste Lamarck theory on evolution

Answer 17

Idea that changes that occur during and organisms lifetime can be inherited (wrong)

Question 18

Darwin

Answer 18

Published ideas in the Origin of Species (1859)

There was much contraversy surrounding these revolutionary new ideas

Question 19

Why was the theroy of evoultion by natural selection only gradually accepted

Answer 19

• It challenged idea God created all animals and plants
• Insuuficient evidence at the time to convience scientists
• Mechanism of inheritance and variation was not known

Question 20

Evidence for Evolution (Darwins right)

Answer 20

• Now can be seen that characteristics are passed from parent to offspring in the genes
• Evidence in fossil records
• Great clear e.g is Antibotic resistant bacteria

Question 21

Evolution

Answer 21

Evolution is the change in the inherited characteristics of a population over time through a process of natural selection which may result in the formation of a new species.

Question 22

Alfred Wallace

Answer 22

• A British scientist who developed the theory of speciation, and therefore evolution by natural selection.
• On his travels, he had the idea that the individuals who did not have characteristics to help them survive a change in the environment would die out.
• He published joint studies with Darwin. The publication of ‘On the Origin of Species’ meant Darwin received the credit for the theory.
• He continued to work across the world to collect evidence – one of his most important works was on warning colouration in animals.

Question 23

Difference between Darwin and Lamarck’s theories of evolution

Answer 23

Darwin stated that any species that had an advantage in its environment would be more likely survive, pass on its genes and therefore that ADVANTAGE would increase in number over years and years

Lamarck stated that changes that occurred in an organism during its lifetime e.g. learning a skill such as playing the piano could be inherited by the offspring.

Question 24

Species

Answer 24

a group of similar organisms capable of interbreeding to produce fertile offspring.

Question 25

How does speciation occur? (6)

Answer 25

1. A population becomes geographically isolated from the original population. E.g. by continental drift. 2. There are different environmental conditions in the new population. 3. Mutations may occur, creating variation in the new population. 4. Natural selection occurs, whereby the best adapted individuals survive and reproduce. 5. The new population eventually changes to the point where it can no longer interbreed with the old population. 6. Speciation has occurred.

Question 26

What are fossils

Answer 26

Fossils are the ‘remains’ of organisms from millions of years ago, which are found in rocks.

Question 27

How are fossils formed?

Answer 27

• Organism dies and is covered in sediment / mud or sinks into the mud. • The soft parts decay or are eaten. • The bones and other hard parts do not decay. • So minerals enter bones and they are preserved. • Conditions needed for decay may be absent. • Preserved traces of organisms, such as footprints, burrows and rootlet traces - these become covered by layers of sediment, which eventually become rock.

Question 28

Why can we not totally rely on fossils for evidence for evolution.

Answer 28

• Fossils form rarely and only in certain conditions. Parts of early organisms were mostly soft bodied so they couldn’t form fossils. • Not all fossils for every organism have been found and there are gaps in the fossil records.

Question 29

How are humans contributing to the extinction of species?

Answer 29

1. Habitat destruction 2. Introduced species 3. Hunting and fishing 4. Environmental change 5. Extinction of a species from a food web/chain 6. Speciation

Question 30

Organisms that cause extinction

Answer 30

- New predators (don't adapt in time) - New diseases - One species cause another to become extinct by successful competition, new mutation can give one species the upper hand (advantage) - New species introduced into an environment by mistake

Question 31

How can enviromental over geological time cause extinction

Answer 31

Massive eruptions and collision with asteroids

Question 32

Classification

Answer 32

* Classification is the way in which living things (organisms) are grouped according to features (characteristics) that they have in common. * More recently classification of organisms is based on DNA analysis.

Question 33

What did Carl Linnaeus do

Answer 33

Classified organisms into 5 kingdoms (based on their structures and characteristics). • He also developed the binomial naming system. • Linnaeus classified living things into: kingdom, phylum, class, order, family, genus and species.

Question 34

Biological naming system

Answer 34

* Each species is given a name that consists of two parts. * The first part is the Genus to which the species belongs. Written with a capital letter. * and the second part is the species name. Written with a lower case letter.

Question 35

When and why were new models of classifications introduced

Answer 35

As evidence of internal structures become more developed due to improvements in microscopes and the understanding of biochemical processes progressed.

Question 36

What did Carl Woese do?

Answer 36

Due to DNA evidence and analysis there is now a different classification system developed by Carl Woese. In this system, organisms are divided into 3 domains: • Archaea: primitive bacteria usually living in extreme environments • Bacteria: true bacteria • Eukaryota: includes protists, fungi, plants and animals.

Question 37

Order of classification

Answer 37

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Question 38

3 Domains and 6 Kingdom system by Carl Woese

Answer 38

Bacteria, Archaea and Eukaryota | Bacteria, Archaea, Protista, Animals, Plants and Fungi

Question 39

5 kindom systems by Carl Linnaeus

Answer 39

Bacteria, Protista, Animal, Plant and Fungi