4.1. Diversity of organisms Flashcards
How does variation differ between members of the same species and between different species?
Greater between species than within (less related organisms)
Who is Carl von Linne? What did he introduce?
Pioneer of biological classification. Morphological species concept.
Outline the two species concept and the problems with those two concepts.
- Morphological species concept – comparison of outward form and inner structure (e.g. western and eastern meadowlark look the same but sing different songs so they never interbreed)
- Biological species concept – members of the same species interbreed (sharing genes from a common gene pool, traits remix each generation preventing them from diverging) and produce fertile offspring (asexually reproducing species (blackberry), different species that naturally interbreed and produce fertile offspring (liger), fossils, bacteria (HGT)
What is the binomial naming system?
A universal name given to each discovered and described species (1st name is the genus name (capitalized) and the 2nd is the species name)
List all taxa.
Domain, kingdom, phylum, class, order, family, genus and species
List all taxa for humans.
Eukaria, Animalia, Chordata, Mammalia, Primatae, Hominidae, Homo and sapiens.
Why and how was domain prokaryotes separated into Bacteria and Archea? List some examples of each.
Their rRNA base sequences were compared, and they were found to be as different from each other as they are form eukaryotes.
Bacteria – E. coli, cyanobacteria, Archaea – thermophile, acidophile, halophile
What are extremophiles?
Organisms that thrive in physically or geochemically extreme conditions that are detrimental to most life on Earth
What is cladistics? What are clades?
Classifies organisms into groups based on their evolutionary relationships.
Groups of organisms that evolved from the same ancestor
What are the different methods of estimating relatedness. Asses their relevance/accuracy.
- Comparative morphology – comparing anatomical structure (not very relevant)
- Comparison of the chromosome number (species with more similar chromosome number are more closely related – grass example, not always accurate)
- Comparison of the base sequence of a gene or amino-acid sequence of a protein – sequence differences accumulate slowly and gradually but they accumulate at roughly constant rate, this can be used as an evolutionary (molecular) clock – the more differences the earlier the species diverged from their common ancestor
What is the estimation of the current species diversity? What is the definition of a mass extinction? How many mass extinction events have happened in the past.
Around 10 million (less than 6000 species discovered). When three fourths of all species vanish. Five, the sixth is underway.
Fifth mass extinction – when, cause, consequence
66 million years ago, a huge asteroid colliding with the Earth which caused environmental disruption and the extinction of all non-avian dinosaurs, evolution of new species of birds and mammals
Sixth mass extinction – type, which species it includes (describe them)
anthropogenic
1. Caribbean monk seal – Caribbean sea and western Atlantic, hasn’t been seen for over 70 years, hunted for its oil and starved due to overfishing of the coral reefs
2. Giant moa – north island of New Zealand, since 15th century, hunted to extinction for meat
3. Silphium – Libya, became extinct within a few hundred years of the arrival of ancient Greeks, harvested for use as a birth control agent and also became extinct due to overgrazing and desertification
Identification of a biodiversity crisis (by evaluating…). What are the causes of a biodiversity crisis?
Species diversity, range of the species and the number of the threatened species.
1. Overexploitation of natural resources (gathering of fuel wood, overhunting, mining and smelting)
2. Global warming/climate change (anthropogenic)
3. Introduction of invasive alien species to ecosystems
4. Habitat destruction (overharvesting, agriculture, urbanization) – due to natural causes or anthropogenic
5. Growing human population
6. Pollution
7. Poor water management (drying of wetlands)
Outline natural vs anthropogenic loss of ecosystems.
Replacement of one with another ecosystem due to natural climate change is a natural thing and it is very long and gradual so the nature can adapt.
Anthropogenic loss of ecosystem is rapid and the nature has no time to adapt which causes loss of biodiversity. E.g. mixed dipterocarp forests replaced with palm trees (imbalance in photosynthetic activity) and Arial Sea loss (ecosystem collapses, biodiversity is lost).
