Unit 1: Diversity of Living things

Biodiversity

Biodiversity is the diversity of living organisms. Biodiversity can be “measured” at three different levels.
- Genetic diversity: Genetic variation of a species. Ex: different traits.
- Species diversity: Different species present in an ecosystem.
- Ecosystem diversity: Variation in ecosystems.

Biodiversity is important for several reasons.

Biodiversity provides humans with services that cannot be found elsewhere.

- Support services: Recycling of elements. Ex: carbon, nitrogen, etc

- Provisioning services: Food, water, fiber, medicine, etc

- Regulating services: Ecosystem and earth balance

- Cultural services: Tourism, nature, etc

Biodiversity makes species and ecosystems resilient to change.
- Imagine a species that only consists of exact copies of itself. They would all fall easily to the same threat, like a disease or a predator. Genetic diversity ensures that some will survive with different traits to overcome different challenges. These traits can then be passed down for the survival of future generations.
- All organisms rely on each other. An example of this is the food web. Strong diversity means that this food web is less susceptible to change. - Taking one species out won’t greatly affect the whole ecosystem. Weak diversity means that this web could collapse easily if something is removed.
- Coral reefs are another example of poor biodiversity, everything relies on the coral, if the coral dies so does the whole ecosystem.

Human impacts: Human actions can have negative consequences on biodiversity. For example: deforestation, global warming, desertification, pollution, habitat loss and more.

Domains and Kingdoms

Bacteria domain:
- Prokaryotic
- Live everywhere except extreme environments

Eubacteria Kingdom

Archae domain:
- Prokaryotic
- Live in extreme environments
- Are more closely related to Eukarya domain

Archaebacteria kingdom

Eukarya domain:
- Eukaryotic
- Naturally live everywhere except extreme environments

Animalia

Plantae

Fungi

Can obtain food in one of four ways

Parasitic: absorbs nutrients from a host

Predatory: traps prey to absorb nutrients

Mutualistic: lives in symbiotic relationships to survive

Saprobrial: Feeds on dead and waste. Necessary in ecosystems. Decomposes and recycles nutrients.

Can reproduce sexually or asexually

Sexually: Example: Spores meets other spores and grows

Asexually: Example: Spores lands in suitable environment to grow

Fruiting Body (part that’s above the ground): produces spore, responsible for reproduction.

Penicillin: Fungi was accidentally allowed to grow on a petri dish of bacteria. Fungi produced toxins that killed bacteria in self-defence. Harvesting this toxin lead to the first antibiotic.

Yeast infections: Humans natural have yeast on and inside us. Yeast can be caused to overgrow, causing an infection. Caused by weakened immune system, hormonal changes, damaged skin, stress and more. Cured with antifungal medicine.

Athlete’s foot: Fungi thrives in moist and warm environments, which is often caused by sweat. Athlete’s foot can also be caused by coming in contact with infected surfaces, especially with an injury. Treat by keeping feet dry and clean.

Protists

Are eukaryotic

Can be unicellular or multicellular

Can be heterotrophs or autotrophs

Three main types of protists

Plant-like protists
- Can perform photosynthesis
- May have flagella

Animal-like protists
- May have flagella
- May have Cilia
- May have pseudopods
- May cause diseases (parasitic)

Fungi-like protists
- Must live in cool, shady, moist environments
- May have flagella

Prokaryotic vs Eukaryotic

Eukaryotic cells are much larger than prokaryotic cells because eukaryotic cells tend to be more efficient and organized at using available resources. This allows them to grow larger.

Eukaryotic cells evolved into existence much later than prokaryotic cells

Membrane infolding: Cell membrane folds into the cell itself. This allows for the creation of new organelles, such as the nucleus.

Some prokaryotic cells show evidence of infolding in their membranes

Endosymbiosis: Engulfing different organisms (not digest) to work together.

Host cell engulfs the endosymbiont.

Host cell may gain the resource gathering abilities of the mitochondria and/or the chloroplast

Endosymbionts gain protection by existing inside the host cell

Bacteria reproduction

Binary fission: form of asexual reproduction

#1: DNA (and plasmid if available) is duplicated

#2: cell elongates

#3: cell splits into two identical cells

Very rapid, low genetic diversity

Conjugation: Transfer of genetic material, no new cell is created, similar to sexual reproduction

#1: Donor cell attaches to recipient cell by attaching a pilus to a receptor site

#2: Plasmid of donor cell is replicated

#3: Strand of plasmid (sometimes the entire plasmid) is cut from the donor cell and enters recipient cell

#4: Cells separate. Recipient cell replicates new plasmid and becomes a donor cell

Increases genetic diversity, slower process, no new cells are made

Antibiotics

Inhibits certain functions of a cell to help eliminate them. For example:

- Prevent cell wall from forming

- Prevent DNA synthesis

- Prevent folate synthesis

- Prevent protein synthesis

Antibiotic resistance

Through mutation and conjugation, bacteria can evolve traits to become resistant to antibiotics. This is problematic as is renders existing medicine ineffective.

Some causes are:

- Overuse of antibiotics, using antibiotics when not needed

- Misuse of antibiotics ; for example, not taking enough antibiotics to completely eliminate all bacteria present in the body, even if no longer feeling ill

- Antibiotics in the food industry: Antibiotics given to animals can pass into our food, causing bacteria in our bodies to gain resistance.

Classifying Life

Species concepts

Biological: Can two organisms interbreed in nature and create fertile offspring?

Ex: Breeding a horse and a donkey fails this test

Morphological: What traits does it share with organisms?

Phylogenetic: Defines species based on shared common ancestors or shared evolutionary history

Taxonomy – the science of identifying and classifying living things

Taxonomy groups species using shared characteristics, getting more specific as you go down a level: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Binomial nomenclature: writing species names

- The first name is the Genus name → This is capitalized

- The second name is the species name → this is NOT capitalized

- The entire name must be EITHER typed in italics OR underlined if written by hand

Characteristics of Living things:

All living organisms:

- Are composed of cells

- Have different levels of organization

- Use energy for growth and maintenance

- Respond to their environment

- Grow

- Reproduce

- Adapt to their environment

Viruses

Non-living entity that carries genetic material.

- Are not made of cells

- Cannot gather energy

- Cannot grow

Lytic Cycle
#1: Attachment: Virus attaches to host cell

#2: Insertion: Virus inserts DNA into nucleus of host cell

#3: Replication: Destroys cell’s DNA, forced to create Virus DNA

#4: Assembly: New viruses are created inside the host cell

#5: Lysis: Cell breaks open, releasing new viruses

Lysis: disintegration of a cell by rupture of a cell wall or membrane

Lysogenic Cycle:

#1: Virus attaches to cell (attachment)

#2: Virus DNA enters cell (insertion)

#3: Virus DNA incorporates into cell DNA

#4: Cells keep replicating until triggered out of the lysogenic cycle

Triggered by change in temperature, immunity, hormones and more.

Dichotomous Keys

- Used to classify living things by their traits

- Use constant characteristics rather than variable ones. (e.g. Flowers change with the seasons)

- Use measurements rather than terms like "large" and "small".