Evolution and biodiversity Flashcards
What is the binomial system?
Each organism is given a specific name of two Latin words
The structure of the names of species?
- the first name is the noun (generic)
- the second name is the adjective (specific name)
Generic name
It begins with a capital letter
Specific name
Begins with lowercase letter
Taxonomy
The science of classification. I relies on morphological characters.
How species are grouped?
- similar species are grouped together into the same genus ( genera plural)
- similar genera are grouped into families
What is taxa?
the general name for groups or categories within the classification system
The hierarchy of taxa
- Kingdom
- Phylum
- Class
- Oder
- Family
- Genus
- Species
What is the classification of living organisms?
- Archaea - extremophile prokaryotes
- Eubacteria - all true bacteria
- Eukarya - all eukaryotic cells
Components of Archea
- 70s ribosomes
- some introns
- few plasmids
- no membrane bound organelles
- few species with histones
Components of Eubacteria
- 70s ribosomes
- no introns
- many plasmids
- no membrane bound organelles
- no species with histones
Components of Eukarya
- 80sribosomes
- introns
- absent plasmids
- membrane bound organelles
- many species with histones
The structure of Eubacteria
- contractile vacuole
- food vacuoles
- nucleus
- cytoplasm
- plasma membrane
- pseudopodia (forms vacuole)
The structure of amoeba
- the cell was is absent
- traps food in food vacuoles
- mobile - moves by cytoplasmic streaming
Plasmodium
- cell wall is absent
- parasitic - feeds on the contents of liver cells and red cells
- mobile - moves into host cells
Paramencium
- cell wall is absent
- plasma membrane contains proteins (pellicle)
- mobile - driven by cilia
Euglena
- cell wall is absent
- largely photosynthetic with chloroplasts
- mobile as they are driven by long flagellum
Chlorella:
- cell wall is present, largely cellulose
- photosynthetic with chloroplast
- non- mobile
Saccharomyces (yeast)
- cell wall made of chitin which is the polymer of glucose
- sapothropic
What are plants?
Terrestrial multicellular organisms that are adapted to life on lands or in aquatic habitats
What organisms are classified as plants?
- eukaryotic organisms that have a wall containing cellulose
- autotrophic organisms, manufacturing sugars into photosynthesis in their chloroplasts
What are the two stages/generations of complex life cycle?
- gametophyte generation that produces gametes
- sporothyte generation that produces spores
What are the main characteristics of plants?
- kingdom: plantae
- photosynthetic
- chlorophyll
- cellulose in the cell wall
- permanent vacuoles
- storing starch
What are the main phyla of green plants?
- mosses and liverworts- phylum bryophyta
- ferns - phylum filicinophyta
- conifers - phylum corniferophyta
- flowering plants - phylum angiospermophyta
Describe mosses and liverworts
- non-vascular plants
- stems radial symmetry (mosses)
-stems bilateral symmetry (liverworts) - no true leaves or roots
- no cuticle
- reproductive structures are called sporangium
- for example mosses, liverworts, hornwarts
Describe ferns
- leaves
- roots
- non-woody stems
- divided leaves
- reproduction includes sporangia
Describe conifers
- trees
- woody stems
- waxy narrow needle-like leaves
- vascular system
- reproduction: microsporophylls (male) - in air bladders and take place in water/air dispersals and macrosporophylls (female) - ovule on the cone scale
Describe flowering plants
- roots
-stems
-leaves - xylem/phloem
- waxy cuticles
- variety of pollen transfers
- produce seeds
Differences between dicotyledons (sunflowers) and monocotyledons (meadow grass)
sunflowers:
- 4 or 5 parts of flowers
- branched roots
- vascular bundles of stem in a ring
meadow grass:
- 3 parts of flowers
- unbranched roots
- vascular bundles of stem numerous and scattered
characteristic features of the animal kingdom
- multicellular eukaryotic organisms
- highly specialized cells
- specialized tissues that form organs
- nervous system to coordinate body
- their life cycle is diploid
- constant movement
- bilateral
- cephilisation
Post-fertilization process in animals
Zygote divides to produce and embryo, which early in the development becomes a characteristic hollow ball of cells- blastula
What is blastula?
hollow ball of cells
What is cephilisation ?
Evolutionary trend towards the centralization of neural and sensory organs in the head
Six main phyla in animal kingdom
- the sponges
- jellyfish
- flat worms
- segmented worms
- mollusca
- jointed-limbed animals
Characteristic of phylum porifera (sponges)
- assymetrical
- no mouth no anus
- pores through body
- sponges
Characteristic of phylum cnidaria (jellyfish)
- radial symmetry
- mouth but no anus
- tentacles with stinging cells
- jellyfish
Characteristic of phylum annelida (segmented worms)
- bilateral symmetry
- mouth
- anus
- segmented body
- leeches, earthworms
Characteristic of phylum mollusca (mollusa)
- bilateral
- mouth
- anus
- muscular foot and mantle
- shelf
- squids, slugs and snails
Characteristic of phylum arthropoda (jointed-limbed animals)
- bilateral
- mouth and anus
- segmented bodies covered with skeleton made of chitin - exoskeleton
- jointed-limbs
- open blood-circulation
- pair of eyes
- spiders, insects
What is clade?
All of the organisms, both living, descended from a common ancestors
What is cladistics?
- method of classifying organisms based on the construction and analysis of cladograms
- each clade consists of an ancestral organism and all of its evolutionary descendants
- members of a clade will possess common characteristics as a result of their shared evolutionary lineage
What is cladogram?
evolutionary tree that shows points at which clades diverged from a common ancestral form
- there is a positive correlation between the number of differences between two species and time difference since they diverged from a common ancestor
What are nodes?
colored circles where the tree branches
What are molecular clocks?
method that uses the rate of genetic mutations in biomolecules (such as DNA or proteins) to estimate the timing of evolutionary events, such as when different species diverged from a common ancestor.
- the number of differences in DNA sequence can be used to deduce how long ago species split from a common ancestor
How the eukaryotic cells evolve from the prokaryotes?
They formed a symbiotic relationship with the cells they engulfed (endosymbiosis). The vital organelles that developed in eukaryote cells were mitochondria for aerobic respiration and chloroplasts for photosynthesis. Primitive eukaryotes acquired mitochondria by engulfing aerobic bacteria and chloroplasts were acquired by engulfing photosynthetic prokaryotes.
What is the evolution?
It is the process by which living organisms are formed, by gradual change from previous organisms. It can occur due to mutations, selection pressures, and barriers to gene flow.
What are the 3 evidences for evolution?
- study of fossils
- artificial selection
- comparative anatomy
How fossils prove the theory of evolution?
- remnants of past life uncovered from the crust of the earth. method of radioisotope revealed the ages of the rock and the fossils in them, which shows the skeletal parts
How artificial selection prove the theory of evolution?
- process by which all the plants and animals used by humans have been developed from wild species by selecting individuals with desirable traits and breeding from them. for instance the cow has been bred to have a straight back and she is the product of artificial selection
How comparative anatomy prove the theory of evolution?
- shows that although organisms adapted to different habitats, their underlying organization can be similar. They have homologous structures which means that they are similar because they have common ancestry. There are also analogous structures, which means that they are similar in structure but have different origins
What is the adaptive radiation?
Describes rapid evolutionary diversification of single ancestral line. It occurs when members of a single species occupy a variety of distinct niches with different environmental conditions.
Natural selection
better adapted organisms survive to produce a greater number of viable offspring. Individuals who are better adapted tend to survive and produce offspring while those less well adapted tend to die
How does natural selection works?
- populations produce more offspring than the environment can sustain
- struggle for survival increases
- organisms that have more favorable traits will survive
- they will pass those characteristics to their offspring and that will lead to a change in the characteristic of the population
Recombination
re-assortment of alleles into combinations different from the parental ones, as a result of the independent assortment, crossing over, or fertilization.
Neo-darwinizm
Essential restatement of the concepts of evolution by natural selection in terms of mendelian genetics
Overproduction of offspring leads to what?
It leads to resource competition since the population size is naturally limited by environmental factors. the majority of organisms fail to survive and reproduce since environment cannot sustain them all.
How the antibiotic resistance works in bacteria?
after the exposure to an antibiotic, the population decreases as only the bacteria with antibiotic resistance can survive. the new generation of bacteria is created. the gene for resistance can arise by mutations, infection or conjugation
why the evolution of multiple antibiotic resistances is rapid?
- widespread use of antibiotics
- bacteria reproduces rapidly
- populations of bacteria is usually huge and can pass the genes through many ways
Species
Group of potentially interbreeding populations
Gene pool
All the different genes in an interbreeding population at a given time
Allele frequency
Proportion of all the alleles of certain gene in a population.
Speciation
Formation of new species from an existing population. The reproductive isolation of populations can include the temporal, behavioral and geographic
Temporal isolation
organisms reproduce at certain times of the year. Differences in breeding schedules can act as the form of temporal isolation
Behavioral isolation
Occurs when the presence or absence of a specific behavior prevents reproduction from taking place
Geographic isolation
Two populations become isolated by a geographic barriers such as mountains, rivers, or oceans
What are the main types of speciations?
-allopatric speciation
- sympatric speciation
Explain allopatric speciation
Physical barrier that separates a species into geographically isolated populations, which develop independently under different conditions and eventually become unable to interbreed.
Explain sympatric speciation
A gene pool can become divided without population being geographically split. A new species arise from an existing species that are living in the same area. Temporal or behavioral isolation can produce significant changes in genetic makeup/distribution.
What is a polyploid?
condition where species may originate from an accident during cell division that results in the extra set of chromosomes. A second form of polyploid occurs when two different species interbreed and produce a hybrid offspring. They are sterile because the set of chromosomes from other species cannot pair during meiosis with the set of chromosomes of other species.
What is the autopolyploid?
An individual that has more than two chromosome sets that are all derived from one species.
What are the three modes of selection?
- stabilizing
- directional
- disruptive
What is the disruptive selection?
Disruptive selection occurs when individuals with extreme phenotypes at both ends of the spectrum have a survival advantage over individuals with intermediate phenotypes. This leads to the divergence of traits within a population, potentially resulting in the formation of two distinct phenotypic groups.
What is the directional selection?
Directional selection is a form of natural selection where individuals with traits at one extreme of the spectrum have a survival advantage over others, leading to a shift in the population’s average phenotype towards that extreme. This occurs when environmental conditions favor one phenotype over others, driving the frequency of the favored trait higher in successive generations.
What is the stabilizing selection?
Stabilizing selection is a type of natural selection where individuals with intermediate phenotypes have a higher fitness compared to those with extreme phenotypes. This results in a reduction of genetic diversity and the maintenance of the average phenotype within the population. Stabilizing selection tends to occur in stable environments where extreme phenotypes are less advantageous.
What are the patterns of macroevolution?
phyletic gradualism and punctuated equilibrium
Phyletic gradualism
evolution occurs by the gradual accumulation of small changes. The intermediate stages of evolution not represented by fossils merely testify to incompleteness of the fossil record. It is a slow process and there are gaps in the fossil that make it hard to estimate the pace.
Punctuated equilibrium
Evolutionary history consists of geologically long periods of little or no evolution interrupted or punctuated by geologically short periods of rapid evolution. Rapid process and there are no gaps.
How species can diverge into separate species via evolution?
- the degree of divergence increase the longer the species are separated
- the genetic compatibility consequently decreases
- two populations will diverge to a point where they no longer interbreed if returned to the same environment.
- they will be considered as separated species
- this process is called speciation
