Biology - Unit 3: Diversity of Living Things

Species

  • A group of organisms that can interbreed in nature and produce fertile offspring

  • There are three definitions of a species, or species concepts

    • Morphological

    • Biological 

    • Phylogenetic

Morphological

  • Defines species based on structure or form of an organism, essentially its physical and internal characteristics (like cells)

Biological 

  • Defines a species based on reproduction, so ability to interbreed in nature and produce fertile offsprings  

Phylogenetic

  • Defines a species based on evolutionary history and relationships 

Taxonomy 

  • Organisms with similar characteristics are grouped together 

    • Eg. Locomiation, feeding patterns, structures 

Binomial nomenclature: 

  • A two-part naming system used to name species universally (linnaeus, 1700s) 

  • The first part is the Genus name (upp. case), the second part is Species name (low. case), all italicised

    • Eg. Homo sapien 


Classification

  • Organisms are classified using 8 nested categories called ranks.

    • Rank: A level in a classification scheme such as phylum 

  • Each Rank is called a Taxon

    • Taxon: A named group of organisms such as phylum Chordata

      • Domain

      • Kingdom

      • Phylum

      • Class 

      • Order

      • Family

      • Genus

      • Species

  • Do Kings Prefer Cake or Flowers Generally Speaking


Species relationships

  • Taxonomists rely on the following to identify and organise species:

    • Morphology: Shape, SIze and other physical characteristics

    • Physiology: Study of function of organism

    • DNA: Number of common nucleotides


Classification of Living Organisms 

  • Cell type

    • Prokaryote 

    • Eukaryote 

  • No. of Cells

    • Unicellular 

    • Multicellular 

  • Cell Wall Material

    • Chitin

    • Cellulose

    • Peptidoglycan 

  • Nutrition

    • Autotrophs

    • Heterotrophs

  • Reproduction

    • Asexual

    • Sexual 







Domain

  •  Bacteria

  • Archaea

  • Eukarya


Kingdom

  • Bacteria

    • Prokaryote, Unicellular, Peptidoglycan, Autotrophs and heterotrophs, Asexual

  • Archaea

    •  Prokaryote, Unicellular, Not peptidoglycan; occasionally no cell wall, Autotrophs and heterotrophs, Asexual

  • Protista

    • Eukaryote, Unicellular and multicellular, Cellulose in some; occasionally no cell wall, Autotrophs and heterotrophs, Asexual and sexual

  • Plantae

    •  Eukaryote, Multicellular, Cellulose, Autotrophs, Sexual

  • Fungi

    •  Eukaryote, Mostly Multicellular, Chitin, Heterophs, Sexual

  • Animalia

    • Eukaryote, Multicellular,No cell wall, Heterophs, Sexual


Types of Diversity

  • Structural 

    • A type of biological diversity that is exhibited in the variety of structural forms in living things (internal cell structure, body morphology) 

  • Species

    • The variety and abundance of species in an given area

  • Genetic

    • The variety of heritable traits (genes) in an interbreeding population

  • Ecosystemic 

    • The variety of ecosystems in a biosphere

Gene pool

  • All the genes of individuals in a population

Resilience: 

  • The ability of an ecosystem to remain functional and stable in the presence of disturbances to its path 

Importance of Biodiversity

  • Allows populations to survive changes in the environment

  • Populations that lack diversity are more susceptible to disease and vulnerable to change

Ecosystem functionality

  • Ecosystems switch greater species diversity exhibit resilience

Ecosystem services

  • Benefits experienced by organisms that are provided by sustainable ecosystems  

Ancestor

  • An organism from which groups of organisms are descended

Anatomy

  • The branch of biology that deals with structure and form, including internal systems 

Physiology

  •  The branch that deals with the physical and chemical functions of organisms including internal processes

Phylogenetic tree

  • A branching diagram used to show the evolutionary relationships among species

Eukaryotic cells

  • Large, complex, membrane bound nucleus structures

Prokaryotic cells

  • Small, simple type of cell with  no membrane bound nucleus 

Dichotomous Keys

  • An identification tool consisting of a series of two part choices that lead the users to a correct identification \

Autotrophs

  • An organism that captures energy and convert it to their own nutrients

Heterotrophs

  • An organism that cant make its own food and so gets it by consuming other organisms



Viruses

  • Non living, infectious agents that are neither prokaryotic or eukaryotic

  • Small, contain genetic material (DNA or RNA), covered in capsid (protein coat)

Non-living

  • Unable to reproduce

  • Do not react to stimuli

  • No cell structure 

  • No cellular respiration

Classifying viruses 

  • Genetic Material

  • Size

  • Shape

  • Disease Caused

  • Method of Reproductions 


Methods of Reproduction 

  • Lytic Cycle

    • Attachment: phage attaches to surface of host cell

    • Entry: Phage injects DNA or RNA into host cell

    • Replication: Host DNA degenerates and is replaced with phage DNA

    • Assembly: replicated material assembles into full viral phages

    • Lysis & Release: Cell wall ruptures and releases phages


  • Lysogenic

    • Attachment: Phage attaches to surface of host cell

    • Entry: Phage injects DNA or RNA into host cell

      • Occasionally, the lysogenic cycle experiences latency period 

    • Integration: Phage DNA combines with host’s bacterial chromosome

    • Cell replication: continued division makes many cells with new prophage DNA

    • Replication: Host DNA degenerates and is replaced with phage DNA

    • Assembly: replicated material assembles into full viral phages

    • Lysis & Release: Cell wall ruptures and releases phages

Vaccines

  • Weaken or killed microbes, toxins or surface proteins containing an agent similar to disease causing microorganism 

  • The agent stimulates the immune system to 

    • Recognize agent as foreign

    • Destroy it

    • Remember it 

Prions

  • Infectious particles cause damage to nerve cell and brain consisting of normally one single protein 


Classifying Bacteria 

  • Cell Shape

    • Cocci (sphere)

    • Bacilli (rods) 

  • Nutrition 

    • Photoautotroph: Photosynthesis

    • Methanogenesis: Obtain nutrients from O2 free environment, CH4 is a byproduct 

    • Chemoheterotroph: Obtain energy from breaking down organic or inorganic compound

  • Habitat

    • Extremophile: lives in extreme conditions

      • Acidophile

      • Halophile

      • Thermophile

    • Mesophile: live sin moderate conditions

  • Gram Stain

    • Gram Positive: cells appear purple, thick protein layer

    • Gram Negative: cells appear pink, thin protein layer \


Reproduction

  • Binary Fission

  • In less favourable conditions, bacteria and archaea will exchange dna by conjugation 

Plasmids are transferred from one cell to another