5 — evolution and biodiversity Flashcards
1
Q
describe how plants are named and classified, including recognition features of plant phyla
A
- binomial naming
- plants constitute a kingdom
- plants are eukaryotes
- classified using a hierarchy of taxa
- bryophyta/ filicinophyta/ coniferophyta/ angiospermophyta is a phylum
- bryophyta have only spores/ no roots/ no vascular tissue
- filicinophytes have stems/ roots/ reproduce by spores/ no seeds
- coniferophytes have seeds in comes/ vascular system/ no flowers and fruits
- angiospermophytes have flowers/ produce seed and fruits/ have vascular tissue
- cladistics is used to reclassify groups of plants
- use a dichotomous key to discriminate among plant features
2
Q
outline the evidence for evolution provided by selective breeding (3)
A
- domesticated animals produced by selective breeding
- specific example of a domesticated animal — wolves to dogs?
- artificial selection eliminates undesirable varieties
- cause significant change over time from the original wild species
3
Q
explain how a newly classified plant species would be classified and named (7)
A
- plant is given a binomial name
- first name is genus and the second name is species
- name of plant species are international
- study the characteristics of the plant
- classify the plant in a group with other similar species
- natural classification corresponds with evolution
- analogous features due to convergent evolution should not be used
- hierarchy of groups — kingdom-phylum-class
- a clade is a group of organisms evolved from a common ancestor
- base sequences used to group organisms into clades
- cladograms show the relationships between clades
- each branch point represents where species are formed via divergent evolution
- species are now classified into a sequence of clades
4
Q
outline the binomial system of classification (4)
A
- a binomial system of names for species is universal among biologists
- allows to classify organisms into groups based on similar characteristics
- every species is given a binomial name
- members of the same species can mate and reproduce fertile offspring
- genus is written first, followed by species
- genus is capitalised, species is lower case
5
Q
explain how evolution may happen in response to environmental change with evidence from examples (8)
A
- variation in population
- variation is due to mutation/ sexual reproduction
- valid example of variation in a specific population
- more offspring are produced than can survive/ populations over-populate
- competitions/ struggle for survival
- example of competition/ struggle for resources
- survival of the fittest/ best adapted/ those with beneficial adaptations
- favourable genes/ alleles passed on
- alleles for adaptations to the change environment increase in the population
- evolution by natural delectation
- evolution is the cumulative change in population/ species over time
6
Q
explain how evolution occurs and which factors can cause the process to be rapid (7)
A
- evolution is a change in the heritable characteristics of a species
- natural selection causes evolution
- overpopulation/ over-reproduction. more oppspring
- competition for sources
- variation in population
- mutation contributes to variation
- adaptation increases changes of survival
- offspring produced by the better adapted
- characteristics passed to offspring by reproduction
- allele frequencies changes
- environmental change stimulates evolution
- example of environmental change — e.g. increase in rainfall/ introduction of antibiotic/ pollution on tree trunks/ lowered pH of aquatic ecosystems
- artificial selection can speed up evolution
7
Q
outline how fossil records can provide evidence for evolution (2)
A
- the sequence in which fossils appear matches the expected sequence of evolution
- comparisons with fossils and living organisms shows change in characteristics from an ancestral form
- fossils of extinct species show that (evolutionary) change has occurred
- can yield DNA for molecular clock analysis
8
Q
outline how overpopulation of a species in a given environment may lead to evolution (4)
A
- more are born than can survive
- there is variety in the offspring
- competition for resources
- only the most able/ adapted survive
- the survivors reproduce and pass on genes
- genes of less able are eliminated/ change in the gene pool
- natural selection occurs
9
Q
state an external feature that is different in cnidaria and mollusca (1)
A
- cnidaria have radial symmetry while mollusca have bilateral symmetry
- cnidaria have tentacles while mollusca do not
- mollusca have a mouth and anus while cnidaria only has one opening
10
Q
state an external feature that is different in mollusca and annelida (1)
A
- annelida are segmented while mollusca are not visible segmented
- annelida may have bristles
- mollusca may have a hard shell while annelida do not
11
Q
describe, using 1 example, how homologous structures provide evidence for evolution (4)
A
- similar structure but different function
- pentadactyl limbs
- similar bone structure but different uses/ functions
- suggests a common ancestor and evolutionary divergence
- process called adaptive radiation
12
Q
discuss the role of genes and chromosomes in determining individual and shared character features of the members of a species (7)
A
- mutation changes genes/ causes genetic differences
- genes can ave more than 1 allele
- different alleles of a gene give different characteristics
- alleles may be dominant or recessive
- both alleles influence the characteristics with codomnance
- all members of a species are genetically similar
- reference to how not all genes are expressed
- genes are inherited from parents
13
Q
describe one type of molecular based evidence to identify members of a clade (2)
A
- base sequences of a gene
- species with the most similarities in base sequence have recently diverged
14
Q
list two types of evidence used to determine which species belong in the same clade (2)
A
- DNA/ base sequences of a gene
- amino acid sequences in a protein/ proteins
15
Q
explain how the process of evolution occurs (8)
A
- evolution is cumulative change in population/ species over time
- population has variations amongst individuals
- due to meiosis
- due to mutations
- certain variations give an advantage to some organisms over others in certain environments
- populations/ species produce more offspring than the environment can support
- individuals of the species compete for the same resources
- the better adapted organisms tend to survive and reproduce
- individuals that reproduce pass on their heritable characteristics to their offspring
- natural selection increases the frequency of heritable characteristics of the better adapted organisms
