Biology #5 Evolution & Biodiversity

  • Created by: MBid89
  • Created on: 12-04-18 12:36
Define evolution
The change in the heritable characteristics of a population over time
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Define speciation
When populations of a species become separated, evolve (aka diverge in characteristics) until they are unable to interbreed to produce fertile offspring
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Explain how the pentadactyl limb is evidence for evolution
The pentadactyl limb is a homologous structure (aka it evolved from a common ancestor) that is shared by birds, mammals, reptiles & amphibians. It shows evolution because the limb has adapted over time to suit different types of locomotion
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Explain how selective breeding of domesticated animals is evidence for evolution
Domesticated animals are bred from wild species with desirable traits therefore selection, both artificial & natural, can cause evolution.
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Explain how the fossil record is evidence for evolution
The anatomy of organisms today can be linked to common ancestors i.e. via carbon dating
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How is melanism (in the peppered moth) an evolutionary effect?
In industrial areas, soot deposits & sulphur dioxide (killing lichens) caused trees to be dark. Light coloured peppered moths were not camouflaged and got eaten by birds. However, a melanistic variety survived & caused species to evolve
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Who is Alfred Wallace?
The scientist who provided Darwin with evidence & motivation to publish The Origin of Species
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What are 3 sources of variation?
1) mutation, producing new alleles 2) meiosis: crossing over & individual orientation, creating new combos of alleles 3) sexual reproduction: random fertilisation of M & F gametes
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What conditions enable natural selection to take place? (5)
1) species produce more offspring than needed 2) struggle for existence/ competition for limited resources 3) variation between individuals 4) some individuals are better adapted than others 5) individs have heritable traits (good & bad)
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What are 'acquired characteristics'?
Characteristics that are acquired during one lifetime (i.e. muscle mass, maybe intelligence) and that therefore are not heritable & are lost when the individual dies. This is because no change was made to the genes themselves, so cannot be passed on.
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What are 2 examples of natural selection in action?
1) Finches with large beaks survived after drought on Daphne Major (Galapagos) because it could eat larger seeds. 2) Genes coding for resistance to antibiotics are transferred to bacteria, creating strains of bacteria that cannot be killed
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What is the binomial system?
The universal system used to give scientific names to new/ discovered species (based on latin/ greek language)..... Avoids confusion of local names. Is a good example of positive collaboration between groups of scientists.
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What are the features of the binomial system? Give an example of a binomial.
1. genus name (upper case 1st letter) 2. species name (lower case 1st letter). e.g. Homo sapiens
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What are the features of dichotomous keys?
Numbered stages. Each stage contains a pair of alternative characteristics. Some alternatives direct reader to a subsequent numbered stage.
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What are dichotomous keys used for?
To identify what species of organism there are in an area being studied (in an ecological investigation)
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What is the most important thing when constructing a dichotomous key?
To use easily observable & reliable characteristics which are present in every member of the species
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What are the 3 domains?
Archaea, Eubacteria & Eukaryota
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What evidence is the 3 domain system based off, and why was it appropriate?
The base sequences of ribosomal DNA. It was used because it is found in all organisms and evolves slowly (so is suitable for studying early forms of evolution)
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What are the 4 kingdoms of the eukaryota domain?
Protoctista, fungi, plantae & animalia. (aka protists, fungi, plants & animals)
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List the hierarchy of taxa
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species (domain; king prawn curry or fat greasy sausages)
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What is vascular tissue and in which plant phyla is it present?
Vascular tissue is the xylem & phloem (transportation system). Present in filicinophytes, coniferophytes and angiospermophytes
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What are bryophytes and what features do they have? (3)
Mosses & liverworts. No true roots: rhizoids instead (like root hairs). Non vascular (minerals absorbed directly into cells). Spores produced in a capsule which develops at the end of a stalk.
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What are filicinophytes and what features do they have? (4)
Ferns. Pinnate leaves (leaves divided into pairs of leaflets). Vascular tissue. Lignified structures. Spores produced in sporangia on underside of leaves.
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What are coniferophytes and what features do they have? (4)
Conifers. Stems are woody. Leaves are needle-like (narrow) with thick waxy cuticle. Vascular tissue. Ovules on female cones; male cones produce pollen; seeds develop on cone.
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What are angiospermophytes and what features of they have? (3)
Flowering plants. Vascular tissue. Embryo divides into either 1 or 2 cotyledon (monocots or dicots). Ovules in ovaries are fertilised and develop into seeds and then fruit.
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What are the 6 non-chordates (invertebrates)?
poriphera (sponges), cnidaria (jellyfish), platyhelminths (flatworms), mollusca (snails, octopus), amnelida (leeches, worms), arthropoda (insects, arachnids, crustaceans)
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What are the 5 chordates (vertebrates)?
Bony fish, amphibians, reptiles, birds, mammals
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What is cladistics?
An approach to biological classification in which organisms are categorised into groups ('clades'). This can be illustrated using cladograms
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What is a clade?
A group of organisms evolved from a common ancestor
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What are homologous vs analogous traits/ characteristics?
Homologous: derived from common ancestor. Analogous: developed by convergent evolution
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How are organisms classified into clades? (2)
Through base sequences in genes or amino acid sequences in proteins. Because these differences accumulate gradually, there a + correlation between no. of differences & time since the clade diverged from their common ancestor.
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Give an example of classification as an ongoing process
The reclassification of figworts. (Original classification based on structure did not correspond with evolutionary origins)
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Card 2

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Define speciation

Back

When populations of a species become separated, evolve (aka diverge in characteristics) until they are unable to interbreed to produce fertile offspring

Card 3

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Explain how the pentadactyl limb is evidence for evolution

Back

Preview of the front of card 3

Card 4

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Explain how selective breeding of domesticated animals is evidence for evolution

Back

Preview of the front of card 4

Card 5

Front

Explain how the fossil record is evidence for evolution

Back

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