SBI3U1 Exam Review

Biodiversity

The variety of life in the world or in a particular habitat or ecosystem

4 Levels of Biodiversity

Genetic diversity, species diversity, ecosystem diversity, structural diversity

Genetic Diversity

The genetic variability among organisms, usually referring to individuals of the same species (ex. Hair color, eye color, height)

Species Diversity

The measure of diversity that takes into account the quantity of each species present, as well as variety

Ecosystem Diversity

The variety of ecosystems in a region (ex. wetlands, ocean, forest)

Structural Diversity

The range of physics shapes and sizes within a habitat or ecosystem, creating microhabitats and a variety of abiotic conditions

Species

A class of things of the same kind and with the same name  

A group whose members are able to freely breed among themselves under natural conditions 

Keystone Species

A species that has a disproportionately large impact on its ecosystem relative to its abundance  

These species play a critical role in maintaining the structural diversity and health of their environment

5 Types of Keystone Species

Predator, Prey, Mutualists, Hosts, and Engineers

Keystone Predator

regulate the population of prey species, preventing any one group from overwhelming the ecosystem (ex. Sea otters, which control sea urchin populations, allowing kelp forests to thrive)

Keystone Prey

species that are a critical food source for many other animals (ex. Krill in the Southern Ocean serve as a critical food source for whales)

Keystone Mutualist

species that form beneficial relationships with others (ex. Pollinators, like bees, and flowering plants) 

Keystone Hosts

organisms that provide habitats for other species, often in the form of shelter or breeding grounds (ex. Trees, like oaks, which support a wide range of birds, insects, and mammals)

Keystone Engineers

species that modify the environment in ways that benefit other organisms (ex. Beavers that build dams that create wetland habitats for other species)

Human Impacts on Biodiversity

Food security 

Medical discovery  

Economic benefit  

Climate regulation and natural disaster protection 

Why is standard naming and classification needed?

Standard classification and naming are needed to differentiate between animal's common names. A scientific naming system prevents confusion and gives every single species a specific name, unique to only them.  

Taxonomy of Living Things

Kingdom  

     Phylum 

          Class 

               Order  

                    Family 

                         Genus 

                             Species  

Speciation

the formation of new and distinct species over the course of evolution

Node

represents a separation in lineage, also known as speciation

Clade

a taxonomic group with a common ancestor

Eukaryote

an organism consisting of a cell or cells in which the genetic material is DNA in the form of chromosomes contained within a distinct nucleus 

Prokaryote

a microscopic single-celled organism that has neither a distinct nucleus with a membrane nor other specialized organelles

Eukaryote VS Prokaryote

Size	Small cell	Large cells
Chromosome	Single chromosome	Many chromosomes
Organelles	DNA is circular, not bounded by nuclear membrane	DNA is nucleus bounded by nuclear membrane
Cell Division and Reproduction	Division by fission  Asexual reproduction	Division by mitosis and meiosis   Sexual reproduction
Cell Type	Unicellular	Multicellular
Aerobic or Anaerobic	Anaerobic (can live without oxygen)	Aerobic (require oxygen)

6 Kingdoms

Archaea, Bacteria, Protista, Fungi, Plantae, Animalia

Archaea

Prokaryotic 

Unicellular 

Autotrophic 

Cell wall 

Asexual reproduction (binary or multiple fission) 

ex. methanogens, thermophiles, halophiles 

Bacteria

Prokaryotic 

Unicellular 

Autotrophic and heterotrophic 

Cell wall 

Asexual reproduction (binary fission) 

ex. salmonella, e. coli, streptococci 

Protista

Eukaryotic 

Mainly unicellular 

Autotrophic and heterotrophic 

Cellulose based cell wall – some have cell walls, some do not 

Sexual and asexual reproduction 

ex. amoeba, slime molds, diatom

Fungi

Eukaryotic 

Multicellular 

Heterotrophic 

Cell walls made from chitin 

Sexual and asexual reproduction 

ex. mushroom, mold, yeast

Plantae

Eukaryotic  

Multicellular 

Autotroph 

Cellulose based cell wall  

Sexual and asexual reproduction

ex. mosses, fern, flowering plants, trees  

Animalia

Eukaryotic  

Multicellular 

Heterotroph  

No cell wall 

Sexual reproduction 

Able to respond to the environment with some form of nervous system 

ex. man, bird, fish, frogs

Archaea VS Bacteria

Archaea have extreme living environment, normally places other organisms would not survive. They reproduce asexually by binary fission. Nitrogen fixation  

Bacteria live in normal environments, like in our bodies. They reproduce asexually by binary fission. Anabolic metabolism  

Lysogenic Life Cycle of a Virus

1. Virus attaches to the host cell and injects genetic material into the cell 

2. The genetic material “hides” inside the cell as the cell is copied over and over  

3. Eventually the cell enters back into the lytic cycle and host cell die  

Lytic Lifecycle of a Virus

1. Virus attaches to cell and injects genetic material into cell. 

2. Inside the cell viral genetic material is copied by the cell 

3. Inside cell new viruses are made 

4. New viruses burst out of host cell and host cell dies 

Parasite

an organism that lives in or on an organism of another species, known as the host, and benefits by deriving nutrients from the cell

Pathogen

a bacterium, virus, or microorganism that causes disease

Ecolgical Importance of Protista

Form base of aquatic food webs, Primary producers in marine environments, Decomposers in soil and water, Oxygen production through photosynthesis 

ex. Phytoplankton: microscopic algae that live in marine ecosystems and produce about half the earth's oxygen. The world's population of phytoplankton is thought to be declining by 1 percent each year, probably because warming ocean temperatures 

Ecological Importance of Protista - Phytoplankton

Phytoplankton: microscopic algae that live in marine ecosystems and produce about half the earth's oxygen. The world's population of phytoplankton is thought to be declining by 1 percent each year, probably because warming ocean temperatures 

Human Disease Connection to Protista - Mosquitos

Malaria: caused by the protists in mosquitos, transmitted by the mosquito 

Five Major Phyla of Fungi

1. Chytridiomycota: fungi with swimming spores, may be single or multicellular 

2. Zygomycota: the bread and fruit moulds, as well as many soil-based fungi  

3. Glomeromycota: symbiotic form of fungus with many plant roots called the mycorrhiza 

4. Ascomycota: yeasts, smuts and rusts that affect many plants (sac fungus – reproductive structures are sacklike structures) 

5. Basidiomycota: mushrooms, puffballs and bracket fungi 

Lifecycle of Fungi

1. The hyphae that grow underground or in their food is usually haploid.  

2. When two haploid hyphae from different “sexes” meet, their nuclei merge and form a dikaryotic cell (having 2 separate haploid nuclei).  

3. From these dikaryotic cells the fruiting body will grow (mushroom) and inside the 2 nuclei will merge to form a diploid nucleus that goes through meiosis to produce new spores. 

4. The spores will then be released and each spore becomes a new hyphae

Lifecycle of Plantae

1. The sporophyte's diploid cells divide by meiosis to produce haploid cells-in plants these haploid cells form asexual spores 

2. As the haploid generation begins the spores grow into gametophyte individuals (sexual stage) 

3. The gametophytes mature, then produce haploid sex cells-gametes 

4. These gametes undergo fertilization to form diploid zygotes 

5. The zygotes grow into sporophyte individuals and the cell cycle continues