Biology Grade 9 Full Notes Alberta

TOPIC 1
SPECIES:
-​ group of organisms that are distinct from any other group
-​ Species share common characteristics and are capable of reproducing with each other to
generate fertile offspring
VARIATION:
-​ Refers to the differences within a group of similar things. No two organisms even within
a population are alike
-​ Ex. height, hair color, etc.
GENES:
-​ Variation we observe is a result of organisms genes (DNA)
-​ Different types of genes results in different characteristics and traits
-​ Genetic variation exists in any natural population and comes from the mutation or
mixing of organisms DNA.
SPECIATION:
-​ This process of change is aided by natural selection
-​ Traits that allow better survival are selected for over time
ECO SYSTEMS, POPULATION, COMMUNITY:
-​ A place where biotic (living) and abiotic (non-living) things interact.
-​ Members of a species that live in the same area and share resources form a population.
-​ When populations of different species live in an area together they form a community.
NICHE:
-​ Within specific communities, animals occupy a specific niche.
-​ An organism’s specific habitat and habitat in a community
-​ It allows for an organism to have access to resources it requires (food, shelter, etc) and
survive.
-​ Niches of a population can vary depending on the area they inhabit due to differences in
resources and the presence of competing organisms.
-​ Broader niche = generalists
-​ Narrower niche = specialists
INTERSPECIES COMPETITION:
-​ If 2 species occupy a common habitat and access the same resource, it’s possible they can
directly compete for it.
-​ Results in a decrease in each species share of the resources.
-​ Limits the size of populations in an area
-​ When similar species have slightly different niches they dont compete for resources
instead they divide the resources among them. This is known as resource partitioning
(share)

, VARIATION:
-​ Variation in species allows for the survival of a species
-​ Different characteristics allow organisms to deal with environmental changes differently
& effectively. Also to adapt to new/changed environments much easier.
-​ The variation allows access to new or alternate niches if required.
Variation or changes in the environments can be
-​ Introduction of disease, Extreme climates (hot, cold, dry, etc), Natural disasters,
Resource scarcity
BIOLOGICAL DIVERSITY:
The variety of species and ecosystems on earth and the ecological processes of which they are a
part.
-​ Ecosystem diversity (biomes)
-​ Community + species diversity (more resources = more diversity)
-​ Genetic diversity (DNA)
TOPIC 2

INTERDEPENDENCE:
As they interact, Each species depends on many other species in the environment.

PREDATOR-PREY RELA:
-​ Example of an interdependent relationship
-​ Populations of predators will fluctuate with numbers of prey. aka predator-prey cycles
-​ Predator species are fed
-​ Prey species are helped because the strongest, healthiest individuals survive to reproduce
-​ Prey species are also kept in check so they don't populate
Another group of independent relationships where organisms are independent on one another
are known as symbiotic relationships

Mutualism
-​ Where both organisms benefit
Commensalism
-​ Where only one organism benefits
Parasitism
-​ Where one organism benefits and the other is harmed