Chapter 18 Interactions of Living Things

Section 18.1 Living vs. Nonliving

Biosphere  part of Earth that supports living organisms.  many different environments within biosphere (ex. grasslands, streams, dessert).

Ecology  study of interactions among organisms and between organisms and their environment.

Abiotic  nonliving, physical features of the environment.  include water, soil, sunlight, temperature, air

Water  50-95% of body  respiration, photosynthesis, digestion all require water

Soil  type of soil determines what plants/trees will grow

Sunlight  light is turned into energy important for life processes  plants/trees depend on it for photosynthesis

Temperature & Air  climate affects what plants grow and what kinds of animals can live there  these factors have an effect on organisms and determine whether or not they are able to live in a certain environment.

Biotic  living organisms in the environment.

 Organism –single individual from a population.  Population –all the individuals of one species (group that reproduces among itself) living in the same area at the same time –members of populations compete with each other for food, water, space, and mates.

 Community –made up of different groups of populations in a given area. –populations of organisms in a community depend on each other for food and shelter.  Ecosystem –made up of several communities and the abiotic factors that affect them.

Section 18.2 Interactions Among Organisms

Population Density  size of a population occupying an area of a specific size.  more individuals = more dense the population.

Limiting Factors  any biotic or abiotic factor that restricts (limits) the number of individuals in a population.  populations cannot continue to grow larger and larger forever (resources are limited such as food, water, space, mates).  as population density increases so does competition.

Carrying Capacity  largest number of individuals an environment can support and maintain for a long period of time.  if population exceeds this then individuals will die off or be forced to move.

Predation  Predation –the feeding of one organism on another.  Predator –organism that does the killing in predation (biotic factor).  Prey –the organism that is killed in predation.

Symbiosis  close relationship between two or more different species (living together).  types include mutualism,commensalism, and parasitism.

Mutualism  type of symbiotic relationship that benefits (is good for) both species.  Ex. lichen – made up of an algae (provides food for fungus) and a fungus (provides protected living space for algae).

Commensalism  type of symbiotic relationship that benefits one person but does not harm or help the other.  Ex. orchids growing on trees in rainforest (tree provides sunlit living space high in canopy for the orchid).

Parasitism  type of symbiotic relationship that benefits the parasite and harms the partner (or host).  Ex. tapeworms

 Habitat –physical location where an organism lives.  Niche –the role of an organism in the ecosystem. –what a species eats, how it gets its food, and how interacts with others are all parts of its niche.

Section 18.3 Flow of Energy

Food Chain  shows how energy from food passes from one organism to another.  Energy moves through an ecosystem in the form of food.  Usually have 3-4 links because available energy decreases at each link. (only 10% moves to next level)

Food Chain  Example: Phytoplankton  insects  perch  bass

Food Web  Series of overlapping food chains.  More complete picture of how energy moves through a community.

Energy Pyramid  Shows that energy decreases at successive feeding step (level).  Usually 3-4 levels because only about 10% of available energy gets passed to the next level since most energy is lost as heat).

Producer or Consumer?  Producer –organism that makes its own food. –Example: plants (photosynthesis)  Consumer –organism that gets energy by eating other organisms.

Types of Consumers  Carnivore –Type of consumer that eats only meat (ex. lion).  Herbivore –Type of consumer that eats only plants (ex. mouse)  Omnivore –Type of consumer that eats both plants and animals (ex. raccoon).  Scavenger –Type of consumer (carnivore) that feeds on the bodies of dead organisms (ex. vulture)  Decomposer –Type of consumer that breaks down waste and dead organisms (ex. mushrooms)

Animal Defense Strategies  prey use these to protect themselves from a predator.

Mimicry  Some animals mimic (or copy) harmful animals to predators away.  Ex. some flies look like bees, some moths look like monarch butterflies

Camouflage  Some organisms match their habitat or surroundings so predators cannot see them.  Ex. walking stick

False Coloring  Some organisms have a false eye on back end to fake out predators so they will bite the tail allowing the organism to escape death.  Ex. butterfly fish

Warning Coloring  Some organisms have bright colors to warn predators that they are poisonous and to stay away.  Ex. arrow frog

Protective Covering  Some organisms have spines, hard shell, etc to protect them and keep away predators.  Ex. turtles, sea urchins, porcupines

Predator Adaptations  Speed  Sharp teeth or claws  Excellent senses (smell, sight, etc.)  Strength  Agile