term 2 Flashcards
Classification
Classification is the process of sorting a variety of different things into manageable groups.
The study of biological classification is called taxonomy or systematics.
A universally accepted system of classification is important as it allows scientists to identify a species based on shared characteristics.
Artificial Classification
Artificial classification sorts organisms into groups based on similar identifiable characteristics.
Organisms are organised into groups based on a limited number of similar characteristics (e.g. the presence of wings or an exoskeleton).
Dichotomous Keys
Keys are used in biology to categorise and identify organisms.
A dichotomous key is a series of statements consisting of two choices that describe the characteristics of unidentified organisms.
Natural Classification
Natural classification organises species into groups organisms that share characteristics that have been inherited from a common ancestor (called homologous characteristics)
A natural classification system considers the degree of evolutionary relationship among organisms.
Hierarchical Classification
Organisms are grouped into hierarchical categories;
Domain, Kingdom, Phylum, Class, Order, Family, Genus and Species.
(do kids prefer candy over fried green spinach).
Kingdoms – Fungi
Fungi are eukaryotic heterotrophs.
Some species grow as single cells; but most are multicellular.
Fungal cell walls contain chitin but not cellulose.
Fungi do not carry out photosynthesis.
Kingdoms – Protista (Protists)
Protists are eukaryotes.
Most protists are unicellular.
The kingdom of protists consists of all eukaryotes that are not plants, animals or fungi - sometimes referred to as the ’leftovers’.
Both autotrophic and heterotrophic protists exist.
Phylum
Kingdoms are further subdivided into phyla (singular: phylum).
All members of a phylum have a common ancestor and similar anatomical features.
Class
Each phylum consists of one or more classes.
Organisms in a phylum are subdivided further into classes based on similar anatomical features.
Order
A class of organisms can be further sub-categorised into orders. Members of an order have more specific characteristics than members of a class.
Family
Orders are sub-categorised into families of closely related organisms.
Members of one family have very similar anatomical features and behavioural characteristics.
Genus
A genus (plural: genera) is a highly specific grouping of species that are very closely related. Two or more species that share unique anatomical structures or behavioural characteristics are considered to be closely related and are placed together in a genus.
Species
A species is the most specific ranking in the taxonomic hierarchy.
Members of one species can interbreed and produce fertile offspring.
Occasionally organisms of different closely-related species can reproduce; however they don’t produce fertile offspring. E.g. a Liger or a Mule.
DNA and the Organism
The DNA found within an organism’s cells makes up its genetic structure and forms structures called chromosomes.
Chromosomes contain genes that code for all of the characteristics of an organism.
Each organism has different genes that code for characteristics to help it survive in its environment.
Adaptations
An adaptation is a characteristic or feature of an organism that will assist the organism to survive in its particular environment.
Why Adapt?
Organisms compete for resources including food and mates.
Organisms that acquire a stable and adequate source of resources have a greater chance of survival and reproduction.
Individuals that are better adapted to their environment are more likely to succeed in obtaining these resources and are more likely to survive and reproduce.
Types of Adaptations
Behavioural Adaptations
Physiological/Functional Adaptations
Structural Adaptations
Animals Behavioural Adaptations
Learning Communication Migration to new habitats Hunting behaviours Huddling Courtship displays and reproductive strategies The formation of symbiotic relationships Altering times the organism is active (nocturnal).
Plants Behavioural Adaptations
The ability to grow without soil (Air plants) and obtain water and nutrients from the surface on which they grow.
Use of removable appendages (tumbleweeds) to relocate to areas that have more suitable conditions.
The ability to climb up other trees to obtain more sunlight for growth.
Animal Physiological Adaptations
The use of hormones and electrochemical signals to generate the desired response.
The synthesis of chemical compounds used to defend an organism from predators and attack/kill prey.
Snakes release venom to kill their prey, skunks and some beetles release foul-smelling substances when attacked by a predator.
Plant Physiological Adaptations
Opening stomata at night instead of during the day.
Photosynthetic cells contain enzymes that convert CO2 into a storage molecule in the vacuole overnight.
The molecule can then be broken down and the CO2 used when light is present.
Animal Structural Adaptations
Hair in ears and eyelashes – prevent debris getting into ears and eyes.
Fur or hair – to prevent heat loss
Wings – to allow for flight (usually)
Strong beaks – to provide the ability to break seeds, etc.
Presence of large ears – to increase surface area to make it easier for animals to cool down.
Streamlined shape – to reduce resistance from air or water when moving/swimming.
Plant Structural Adaptations
Thick bark – to store water and reduce water loss when water is scarce.
Thick, waxy cuticle on leaves and stomata on un– to prevent water loss through evapotranspiration.
Large, flat leaves – to increase surface area to absorb light.
Leaves or flowers forming cups, pitchers or traps to catch insects – provides them with nutrients they can’t obtain from their natural environment.
Vertically hanging leaves – reduces the amount of time the surface of leaves are in direct sunlight to reduce evapotranspiration.
Ecosystems
Ecosystems are defined by their biotic and abiotic components and the interactions between elements of these components.
An ecosystem is a community of interacting populations and their physical environment. These include:
Biotic Factors: the living components of the ecosystem
Abiotic Factors: the nonliving components of the ecosystem
Biotic Factors
Producers (e.g. plants)
Consumers (e.g. animals)
Decomposers (e.g. bacteria)
Competitors/Pathogens
Producers (e.g. plants)
Autotrophs that convert inorganic materials into organic materials using sunlight or chemical energy.
Consumers (e.g. animals)
Heterotrophs that obtain organic materials and energy through the consumption of other living things.
Decomposers (e.g. bacteria)
Heterotrophs that break down (decompose) dead or decaying organisms
Competitors/Pathogens
Organisms that compete for the same resources or infect an organism preventing their ability to reproduce and survive.
Abiotic Factors
Sunlight Water Atmospheric and Dissolved Gases Temperature Soil Fire
