characteristics of animals
in the 1700s, a man named Carl Linnaeus (Carl Von Linne), introduced a new type of classification
it grouped them into:
kingdoms - division based on basic cellular structure and nutritional methods
phylum - division based on body structures (chordata - vertebrates)
class - division of phyla (plural of phylum) based on common traits
order - grouping of related families
family - groups related by a common ancestor
genus - a group of closely related species
species - specific epithet - organisms that can interbreed and produce fertile offspring
the names are mostly in latin
humans are:
animalia - kingdoms
chordata - phylum
mammlia - class
primates - order
hominidae - family
homo - genus
sapiens - species
linnaeus proposed the binomial naming system (binomial nomenclature), where animals are classified by genus and species
it has to be written all in italics
as we learn more about internal structures, new models have emerged and got combined with the linnaean system
Carl woese proposed the three domain system
using evidence from techniques that analyse rna sequences
he realized that some species were not related as much as we thought
he introduced a new classification called domain that was placed above kingdom
an example of a domain is eukaryote, all organisms that are eukaryotic
another one is bacteria, which are very tiny single-celled organisms found almost everywhere (true bacteria)
and archaea, which are different type of prokaryotic cells found in extreme conditions (primitive bacteria)
evolutionary trees
these show the relationships between different species or groups
for example, birds are more closely related to t-rex’s than to bats because they share a more recent common ancestors
to know this dna had to compared to find these common ancestors
a mnemonic for the classifications is
Dear Kate, Please Come Over For Great Spaghetti
characteristics
these are the features that all living organisms
to remember this you can use the acronym
M - movement
R - Respiration
S - sensitivity
G - growth
R - reproduction
E - excretion
N - nutrition
only living things have all 7 features
movement
the ability to move whether it be the entire body or just part of it’s body
respiration
a set of chemical reactions in our cells that break down nutrient molecules and release energy for metabolism
metabolism are all the chemical reactions that are needed to keep us alive
sensitivity
ability to detect and respond to internal and external stimuli such as, changes in temperature
growth
organisms can get larger or a permanent increase in size and dry mass (the mass of an organism once you remove all the water)
reproduction
the process that makes more of the same kind of organism
excretion
the removal of the waste products of metabolism (urea, carbon dioxide etc.) and things that are in excess inside the body (water, mineral ions etc.)
nutrition
the taking in of materials for energy, growth and development
for an animal, eating or drinking
for fungi or bacteria, this means absorbing things from their environment
dichotomous key
there are five scientific names in the dichotomous key
1a. cell(s) are prokaryotic… go to 2 (does not contain a nucleus)
1b. cell(s) are eukaryotic… go to 3 (contains a nucleus)
2a. cell wall(s) contains peptidoglycan… it’s escherichia coli
cell wall(s) does not contain peptidoglycan… it’s methanopryus kandleri
3a. autotrophic… it’s chlorophytum comosum (makes it’s own food)
3b. heterotrophic… go to 4 (relies on other organisms)
4a. organism is multicellular… it’s agar it’s bisporus (has multiple cells)
4b. organism is unicellular… it’s amoeba proteus (has one cell)
amoeba
feeds on other organisms
contains a nucleus
specimen a is 700 micrometers in length
plant
photosynthetic
cells that make up organism have nuclei
specimen b is 60cm in height
bacterium
lacks a nucleus
cell walls contain peptidoglycan (amino acid and sugar polymer)
specimen c is 2 micrometers in length
mushroom
feeds on decaying matter
cells that make up organism have nuclei
specimen d is 5 cm in height
archaeon
lacks a nucleus
cell walls lack peptidoglycan (amino acid and sugar polymer)
specimen E is 5 micrometers in length
kingdoms of life
plant kingdoms
algae
these don’t have roots, stems or leaves
they live in water
they are the simplest
moss
they live on solid ground
they require a lot of humidity
they don;’t have roots to absorb water because they live in humid places
ferns
their body is divided into roots stems and leaves
they also live in humid places
phanerogams
they are the most common because they reproduce their flowers
their bodies are divided into roots, stem and leaves as well
an example is a tree
dicotyledons - a plant with two embryonic leaves or cotyledons
monocotyledons - a plant with on embryonic leaf or cotyledons
types of flowering plants
angiosperms
these flowering plants produce seeds that are enclosed in a fruit or ovary
these rely on animals, birds, insect etc.
this produces flowers for reproduction
these have more diverse root systems, usually taproot (dicots) or fibrous roots (monocots)
these often produce hardwood
these are either seasonal (deciduous) or evergreen
gymnosperms
these flowering plants produce seeds that stay on the surface of the scales or leaves
these produce cones (strobili) for reproduction
these are wind-pollinated plants
they usually have a more penetrating root system like the taproot to access deep water
these produce softwood products
these are usually evergreen
vertebrates
the animals with backbones are called vertebrates
these are split into smaller groups
amphibians - e.g
they can live both on land and water
they are cold blooded
they lay eggs coated in jelly
they have gills to breathe under water and lungs to breathe on landfill
reptiles
they are made of dry scales
they lay their eggs on land
they spend most of their time under water and only come up sometimes
they are also cold-blooded
birds
they have feathers and wings but not all birds fly
they lay eggs with hard shells
they are warm blooded
mammals
they give birth to young ones instead of laying eggs
they have lungs to breathe
they have hair or fur
they have special glands to produce milk for the young ones
DNA base pairing
dna has two strands and is composed of nucleotides
it is a double helix (two strands coiled together)
the nucleotides include
adenine
thynine
cytosine
guanine
rna uses the less expensive but less stable nucleotide u
if one strand has an adenine, the other will have a thynine
if a strand had cytosine, then the other has guanine
adenine and thymine form two hydrogen bonds while guanine and cytosine form three
base pairings are how dna is replicated
arthropods and annelids
these are the most diverse group of animals, making up over 80% of all species
annelida - these are made of segments that look like rings
synapomorphy - traits that set a group of animal apart from their ancestors and other animals with common ancestry
chaetae - these are things annelids have that help them move through dirt
plesiomorphies - basic traits shared by animals with common ancestry
oligochaetes - these have chaetae but only have few of them
these eat soil and their poo is rich in things that plants need to grow
hirudinea
these are mostly parasitic
their synapomorphy is their suckers
polychaetes
they have lots of chaetae
arthropods include scorpions, butterflies and lobsters
they have segmented bodies
they all have an exoskeleton (an outer shell made out of chitin)
they have paired and jointed appendages
they are grouped into four
chelicoriformes
these have simple eyes with one lens
the largest class are the arachnids
these have a cephalothorax - a head and thorax segment fused together
myriapods
these have many feet
all of these are terrestrial, they all have antennae and jaw-like mandibles
they are vegetarian
hexapoda/insects
these have six legs
they have a three part body (head, thorax, abdomen), six jointed legs, a chitinous exoskeleton, one pair of antennae and usually wings
crustaceans
these have a hard chitinous exoskeleton, segmented bodies, and two pair of antennae
they usually breathe via gills
kingdoms of life
animals, plants, fungi and protoctists are all eukaryotic
this means their DNA is in the form of chromosomes and is found in the nucleus
bacteria is prokaryotic
their DNA is loose in the cell and they do not have a nucleus
animals - 5 - 10 million species
they are multicellular
they are heterotrophs/do not make their own food and get energy from other organisms
the mostly reproduce sexually
plants - 300,000 species
these are multicellular
they are autotrophs rather than heterotrophs meaning they get energy from the sun
fungi
they are either multicellular or unicellular
fungi cannot photosynthesise so they are heterotrophs
they are rather considered saprotrophs because they feed using saprotrophtyc nutrition
this is the process where they secrete digestive enzymes onto food, break down the food and then absorb the nutrients
some multicellular ones have a body called mycelium which is made up of hyphae
some fungi can cause disease in humans
protoctists
they are usually single-celled organisms
most have nothing to do with humans but some of them do cause disease
bacteria
they are prokaryotic and live everywhere
some of them can photosynthesise but none have chloroplasts
they usually feed off of other organisms whether dead or alive
many are helpful because they sometimes aid in digestion
viruses
these are tiny particles that don’t count as cells
they have a protein coat surrounding some genetic material
they only reproduce inside living cells
therefore they are considered parasites
they can all be thought of as pathogens