Living Things Study Guide
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Taxonomy – Memorize the Levels of Organization
Living things are classified based on their physical characteristics and internal structures. This
classification process is known as taxonomy. The major levels of taxonomy include: Kingdom, Phylum,
Class, Order, Family, Genus, and Species. (Remember using King Philip Came Over For Good Soup or
Kids Playing Chicken On Freeways Get Smashed)
Memorize The Six Kingdoms of Living Things.
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2 Bacteria (Archaebacteria & Eubacteria) – Single celled organisms with no nucleus
Plants (Plantae) – multi-celled organisms that make their own food using the sun’s energy
through a process called photosynthesis.
Fungi – decomposers feeding off decaying material.
Protista – single-celled organisms; examples include amoebas & algae
Animals (Animalia) – multicellular organisms that get food from other organisms.
Animal Kingdom
The animal kingdom can be divided into vertebrates and invertebrates.
 Vertebrates have a spinal column, or backbone, running the length of their body;
invertebrates do not. Vertebrates are often larger, have more complex bodies, and are more
intelligent than invertebrates.
 Although vertebrates have many advantages there are a lot more invertebrates in the world!
(More species and more individuals).
Classes of Vertebrates
There are five major classes of vertebrates: Fish (Osteichthyes), Reptiles (Reptilia), Amphibians
(Amphibia), Birds (Aves), and Mammals (Mammalia). All are vertebrates and each class has
certain defining characteristics.
Fish
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There are three basic types: bony fish, cartilaginous fish (sharks and rays), and jawless fish
(lampreys).
Fish are ectothermic vertebrates.
They are aquatic (spend their lives in water).
Their skin is generally covered with scales.
Their limbs are modified into fins for swimming.
They breathe with gills.
Most lay jelly-like eggs that must be in water.
Amphibians
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Amphibians are ectothermic vertebrates.
Their skin lacks scales, hair, and feathers, and is either smooth (like a frog) or rough (like a
toad). Their skin must remain moist to aid in breathing.
They lay eggs in water, which hatch into an intermediate life form (tadpole or larva) that
usually breathes with gills.
Amphibians undergo metamorphosis and change into an adult form that breathes air and
can live outside water.
Examples of amphibians include frogs, toads, and salamanders.
Reptiles
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Reptiles are ectothermic vertebrates.
Their skin is covered in scales which help keep water in/out.
Most reptiles lay eggs with a leathery shell.
Reptiles have lungs and breathe air.
Reptiles include crocodilians, lizards, snakes, and turtles/tortoises.
Birds
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Birds are endothermic vertebrates.
Their skin is covered with feathers.
Their bones are lightweight and usually hollow.
Their forelimbs are wings and most can fly, although penguins and ostriches cannot.
They lay hard-shelled eggs.
Birds have beaks which are specially adapted to help them eat
Mammals
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Mammals are endothermic vertebrates.
They have hair, although the type varies greatly among species.
Mammals feed milk to their young.
Most are placental mammals and give birth to live young. Some are marsupials – their
young continue to grow in a pouch. The platypus is a monotreme, a rare form of mammal
that lays eggs.
Mammals have a high metabolism rate.
Mammals have highly developed brains.
Big Concepts – Multiple Choice and Short Answer
Ectothermic means "external temperature," and replaces the term "cold-blooded." It
means a body temperature equal to the surrounding environment. Reptiles, fish, and
amphibians are ectothermic. The advantage to being an ectotherm is that the animal
doesn’t have to ‘waste’ energy producing body heat. This allows them to survive with a lot
less food than warm-blooded animals. The disadvantage is that they can only live in
certain environments.
Endothermic means “within heat,” and replaces the term “warm-blooded.” Some
organisms use energy to control their body temperatures. To do this they need a high
metabolism rate. Birds and mammals are endothermic. The advantages of being an
endotherm include being able to live anywhere (including the Arctic) and having lots of
energy to move around. The disadvantage is that endotherms need a lot more food than
‘cold-blooded’ animals. A mammal may need 30 times the food that a reptile the same
size requires.
Learned behaviors – These are acquired traits. These behaviors are not inborn, but
rather have to be learned through teaching or trial-and-error. They are not
automatically passed to the next generation. Examples include a child learning English, a
raccoon looking for food in a trash can, a bird talking, or an octopus opening a jar.
Physical Adaptation – changes in the structure of an organism to become more suited
to an environment. They usually help an organism to eat, to not be eaten, or to
reproduce.
Survival – For a species to survive, they must be able to fulfill these three basic functions.
1) Eat. 2) Not Be Eaten. 3) Reproduce. When one of these three functions is severely
interrupted a species can face extinction.
Symbiotic Relationships – In a symbiotic relationship, two different species of
organisms live close together. One member always benefits from the relationship. The other
may benefit, be harmed, or be unaffected by the relationship.
Vocabulary – These will be matching on the test.
Physical Adaptation – changes in the structure of an organism to become more suited to an
environment. They usually help an organism to eat, to not be eaten, or to reproduce.
Photosynthesis – plants make food and oxygen from CO₂, water, and light energy.
Food Chain – Shows the predator-prey relationships between species in an ecosystem. Carnivores
eat herbivores which eat plants which get energy from the sun. All food chains begin with the sun’s
energy.
Mutualism – A symbiotic relationship in which both species benefit.
Commensalism – A symbiotic relationship in which one species benefits and the other is
unaffected.
Parasitism – A symbiotic relationship in which one species benefits and the other is
harmed.
Instinct – A behavioral adaptation that is inborn (doesn’t need to be learned). They are passed on
from generation to generation making them inherited traits. Examples include: a baby cries when
hungry, birds build a nest, salmon swim upstream to lay eggs.
Extinction of a species occurs when the environment changes and the characteristics of a species are
insufficient to allow survival.
Extant – The opposite of extinct. Extant species are currently alive.
Life span –The length of time that an organism is alive.
Natural Selection - Species with certain traits are more likely than others to survive and have
offspring in particular environments.
Metabolism Rate – The rate at which an organism uses energy.
Carnivore – A carnivore eats other animals.
Herbivore – An herbivore eats plants.
Omnivore – An omnivore eats both plants and animals.
Gestation Period – The length of time it takes for young to develop inside their mother.
Range – The locations on the globe where a species is found.
Habitat – The specific environment in which a species lives (Wetlands, Arctic tundra, Jungle, Deserts).