EVOLUTION

Question 1

what is evolution

Answer 1

• a general term that may be defined as a change over time that occur in chemicals, matter, solar systems and language

Question 2

what is biological evolution

Answer 2

• can be described as a genetic changes in a population of living organisms that are inherited over successive generations due to natural selection ultimately resulting in a new species

Question 3

what is macro evolution

Answer 3

• this is the development of new life forms or species form earlier life forms over many generations

Question 4

what is micro evolution

Answer 4

the variations that occur within a species. small changes originate in the gene pool resulting in small changes in the genotype of the species - these changes are passs onto the the offspring

Question 5

is evolution a hypothesis or a theory

Answer 5

• a scientific theory

Question 6

what is the origin of ideas about origins

Answer 6

• the earth was created 4.6 billion years ago and we evolved from one common ancestor that lead to the enormous biodiversity we currently have

Question 7

what are the 5 factors that are evidence of evolution

Answer 7

fossil records
modification
biogeography
genetics
other forms of evidence (comparative biochemistry; vestigial organs and comparative embryology)

Question 8

what are homologous structures

Answer 8

similar structures with the same body plan that perform different functions - these then used to provide evidence of a common ancestor

Question 9

what is biogeography

Answer 9

• the study of the distribution of existing and extinct plant and animal species in specific geographical regions.

Question 10

what are the 3 major observations when studying the natural environment

Answer 10

• biodiversity
• organisms are well adapted
• continuous changes

Question 11

erasmus darwin

Answer 11

his ideas
- single common ancestor
- similarities of species mean the one species developed from another
- artificial selections and metamorphosis

Question 12

jean baptiste de lamarck

Answer 12

his theory
- the use or disuse of organs may cause organs to increase or decrease in size
- during lifetime organisms acquire certain changes in characteristics that are inherited by their offspring

Question 13

alfred wallace

Answer 13

worked along side charles darwin to publish an article on natural selection

Question 14

charles darwin

Answer 14

4 main observations
- individuals of population produce more offspring than required to ensure survival
- a great deal of variation occurs within a population
- some individuals are better adapted and more likely to reproduce
- characteristics are transferred from surviving parents to offspring

Question 15

what is darwin’s theory of natural selection

Answer 15

• a large number of offspring produced
• variation in a population
• struggle for survival
• survival of the fittest
• inheritance of favourable characteristics
• change occurs over time
• new species form

Question 16

what is punctuated equilibrium

Answer 16

• the fossil records show us fast and rapid change not gradualism like darwin suggests - either the species could not adapt and died or it did but rapidly leading to speciation
• it explains the absence of transitional fossils

Question 17

what is natural selection

Answer 17

• survival of the fittest “nature decides”

Question 18

what is artificial selection

Answer 18

• in the deliberate breeding of plants and animals for desired characteristics that would not necessarily benefit the survival of offspring - sheep for wool, race horses for speed etc

Question 19

differences between natural and artificial selection table

Answer 19

N
: environment acts as selection pressure
: characteristics are advantageous for survival in natural environments
: maintains variation
A
: humans decide
: characteristics not necessarily advantageous
: decreases variation

Question 20

two types of variation

Answer 20

continuous - a range in phenotypes from the same characteristic forms a spectrum
- a genetic characteristic may be controlled then more than 1 gene (poly genetic) and each gene may have multiple alleles - the more alleles that control a characteristic the greater the variation of possible gene combinations (eg human height)
discontinuous - phenotypes fit into separate categories eg blood type - you can only be one

Question 21

What are the conditions essential for fossilisation

Answer 21

Rapid burial
High pressure
Low oxygen

Question 22

What is divergent evolution

Answer 22

Where organisms develop from a common ancestor but follow different evolutionary paths

Question 23

What is convergent evolution

Answer 23

Where organisms are not related but develop structures for similar environments completely independent of each other

Question 24

What are analogous structures

Answer 24

Preform same function but did not originate from a common ancestor

Question 25

What are analogous structures

Answer 25

Preform same function but did not originate from a common ancestor

Question 26

What is the theory relating to the flightless birds

Answer 26

May have developed from a common ancestor, the birds were separated when Gondwanaland broke apart - the climate and habitat changes as a result of continental drift - the birds adapted and a new species developed due to the mutations and selections in various environments

Question 27

What are 3 other forms of evidence (not the main 5)

Answer 27

Comparative biochemistry Vestigial organs Comparative embryology

Question 28

What is speciation

Answer 28

The formation of species increases the range of organisms on earth and thus increases biodiversity

Question 29

What is a species

Answer 29

A group of organisms that interbreed to produce fertile offspring

Question 30

What is extinction

Answer 30

The loss of species decreases the range of organisms on earth and thus decreases biodiversity

Question 31

What is a population

Answer 31

A group of organisms of the same species that live in a particular place and at a particular time with the ability to freely interbreed

Question 32

What is a gene pool

Answer 32

A total number of allelles of all reproductive individuals in a particular population

Question 33

What is a gene flow

Answer 33

The exchange of alleles between population

Question 34

What is reproductive isolation

Answer 34

When a new species arise from an existing species, the two species can no longer interbreed: there is therefore no gene flow and they become isolated from each other in terms of reproduction

Question 35

When can reproductive isolation occur

Answer 35

When the species is separated geographically Or when they occupy the same area (new species arise)

Question 36

What is genetic variation in a species usually caused by

Answer 36

Genetic recombination - meisosis( crossing over and random assortment of homologous pairs ) - reproduction (random mating and random fusion of gametes) Mutations - gene mutations (change in base sequence - either harmful, neutral or beneficial) - chromosome mutation (eg Down syndrome)

Question 37

Mutations lead to genotypic variations in population, what are 2 examples

Answer 37

- finches of the Galapagos island - white lions

Question 38

What is inbreeding

Answer 38

Crossing of closely related individuals - usually occurs in mostly treated species where there are limited numbers of individuals or in populations with small isolated gene pools Bc closely related individuals share more alleles it leads to a limited genotypic and phenotypic variation Increase in homozygosity - if both recessive genes are carrying harmful mutations they will be expressed in the phenotype therefor passed to next gen

Question 39

List 2 advantages and disadvantages of inbreeding

Answer 39

+ produces predictable offspring, recessive genes can be isolated - high mortality rate, offspring can become sterile

Question 40

What are the 2 genetic disorders that occur in humans as a result of inbreeding

Answer 40

Haemophilia Tay seach’s

Question 41

What is outbreeding

Answer 41

The crossing of unrelated individuals resulting in offspring that are genetically different- Promotes heterozygosity where alleles differ from each other and increase genetic variation

Question 42

List 2 advantages and 2 advantages of outbreeding

Answer 42

+Genetic variation increases, reintroduces lost charactistic - less predictability in offspring, typical characteristics are lost

Question 43

Explain the founder effect

Answer 43

A loss of genetic variation when a new population is formed from a small number of individuals moving to a new area - the gene pool will only contain genes from the founding members - according to evolution the isolated pop will become so different to the parent pop it can eventually form a new species

Question 44

What are the 2 main types of speciation

Answer 44

Geographic (allopatric) speciation Sympatric speciation

Question 45

Define allopatric speciation

Answer 45

Is when a new species arised from an existing species when the populations are separated by a geographical barrier These two populations are reproductively isolated and there is no gene flow Natural selection occurs independently in each area and the two gene pools become very different in phenotype and genotype Eventually a new species develops

Question 46

Define sympatric speciation

Answer 46

Is when a new species arise from an existing species in the same geographical area The new species can become isolated from the ancestoral species with respect to reproduction even if they occur in the same area Sympatric speciation can occur as a result of polyploidy plants (multiplication in chromosome no.) and hybrid species (breeding of unrelated individuals [different species])

Question 47

What are the 2 main groups of reproductive isolating mechanisms

Answer 47

Pre zygotic Post zygotic

Question 48

What are some examples of pre zygotic isolation

Answer 48

Breeding at different times of the year Species specific courtship Adaptations to plant to different pollinators Physical Incompatibility in animals to prevent fertilisation Occupying different habitats in same environment

Question 49

What is an example of post zygotic isolation

Answer 49

Development of sterile offspring in hybrids