IB Biology Ecology Unit

Biosphere

What term describes the portion of the Earth that supports life?

Type III

What type of survivorship curve represents a population whose members mostly die young?

Commensalism

A bird nesting in a tree is an example of ____

Wasp

Which of the following organisms can be a parasitoid?

Secondary Succession

A fire destroys an ecosystem. What type of succession describes its recolonization?

Energy pyramid

What diagram shows the total energy at each trophic level?

Exponential

What type of population growth has a J shaped curve?

Lichen

Which of the following is a composite organism?

Uniform

What type of population dispersion is seen in an orchard?

Reproductive rate

In ecology equations what does r represent?

Taiga

Which type of biome has mostly conifer trees?

Desert

Which biome has the least precipitation?

Chaparral

Which type of biome is seen in Orange County?

The study of living organisms’ interactions with their environment, living and non-living

Ecology

living factors in the ecosystem that affect other living things

Biotic factors

non-living factors in the ecosystem that affect other living things

Abiotic factors

a group of individuals of one species living at the same place at the same time (N)

Population

a group of populations living at the same place at the same time

Community

all of the living and non-living factors that affect an organism in a specific area, describes the interrelationships between the organisms in a community and their physical environment

Ecosystem

portion of the Earth that supports life

Biosphere

where an organism lives out its life, a description of the habitat may include other organisms that live there (often dominant vegetation) as well as the physical and chemical characteristics of the environment (such as temperature, soil quality, or water salinity)

Habitat

an organism’s role in the ecosystem

Niche

two species can't coexist if they occupy exactly the same niche (competing for identical resources)

Competitive exclusion principle

division of resources to avoid interspecific competition for limited resources in an ecosystem

resource partitioning

the niche that an organism occupies and prevents competition, occurs after resource partitioning

Realized Niche

the niche that an organism occupies in the absence of competing species

Fundamental Niche

the study of the growth, abundance, and distribution of populations

Population ecology

(represented by N) is the total number of individuals

Size

the number of individuals of a given species that occurs within a given sample unit or study area

Density

arrangement of individuals within a habitat at a particular point in time

Dispersion

the amount of organisms in one area

Population density

low populations are grouped

Population dispersion

when individuals are spaced closely together

Clumped

evenly spaced

Uniform Dispersion

dispersion has no pattern

Random Dispersion

a description of the abundance of individuals of each age. It is often graphically expressed in an age structure diagram
- Pyramid shape, suggests rapid growth
- Tiers of equal width depict slow growth
- When the top and bottom have the same size there is zero population growth

Age Structure

most likely to die when old

Type 1 Survivorship Curve

Equal chance of death at any age

Type 2 Survivorship Curve

most individuals die young

Type 3

the maximum growth rate of a population under ideal conditions

Biotic Potential

the maximum number of individuals of a population that can be sustained by a particular habitat

Carrying capacity

agents whose limiting effects become more intense as the population becomes bigger

Density-dependent factors

occur regardless of population size

Density-independent factors

(births-deaths)/N

r=

the reproductive rate

R

the population size

N

intrinsic rate

When the reproductive rate is maximum (biotic potential) it is called the ____

0

Zero population growth occurs when birth-death equals __

have good dispersal capabilities, exhibit rapid growth, are short-lived, have little parental care, exhibits a J-shaped curve/exponential growth

R-selected species

organisms whose population size remains relatively constant, logistic growth (at the carrying capacity), long-lived, few offspring, a lot of parental care, exhibits an S-shaped curve/logistic growth

K-selected species

a relationship between two or more species

Symbiosis

a type of symbiosis where both species benefit

Mutualism

a type of symbiosis where one benefits while the other receives no benefits nor harm

Commensalism

a type of symbiosis where one species benefits and the other is harmed

Parasitism

kills and eats animals

True predator

an organism that lives on another organism and feeds on its tissues

parasite

insects that lay eggs inside a host. The larva then devours the host until they are fully developed

Parasitoids

feed on plant matter

Herbivore

(eats grain)

granivores

(eats fruits)

frugivore

(eats grass)

grazers

(eats leaves)

browsers

series of changes in a community, ultimately resulting in a stable community

Ecological succession

succession that occurs in an area that has never had life before, on substrates that never previously supported living things, pioneer species involved, all rock no soil

Primary succession

begins in habitats where communities were entirely or partially destroyed by some kind of natural disaster or climax community, life has occurred where secondary succession occurs, faster succession because soil has already formed

Secondary succession

end result of succession is colonized by slower species, populations remain stable

Climax community

tend to be the first species in a new habitat, can live in marginal habitats, bad at competition

Pioneer species

one that barely supports life

Marginal habitat

composite species, consisting of an algae, fungi, and a yeast species, lives on bare rock and creates soil by eroding rocks

A lichen is a

show the among of energy at each trophic level

Energy pyramids

the amount of arrows represent the flow of energy

In a food chain...

an expanded more complete version of a food chain

A food web

10%

Only __ of energy can be passed from one trophic level to the next

the amount of matter of a living thing

Biomass

represents the biomass at each trophic level

Biomass pyramid

a way to illustrate energy flow and the production and utilization of energy

Trophic levels

a group of similar ecosystems

Biome

Temperature and precipitation

_______ determine which biome is where

year-round high temperatures and precipitation

Rainforests

can be hot during the summer and possibly cold during winter and night, dry

Deserts

most trees are conifers, which are shaped to shed snow, low temperature during winter, moderate precipitation, moderate temperature and precipitation during summer

Taiga

low-temperature moderate precipitation during winter, during the summer high temperature and moderate precipitation

Deciduous forests

high temperatures low precipitation, during the winter moderate temperature moderate precipitation

Chaparral

Climate

______ is a strong determinant of biodiversity

type of population growth that grows slower as population size increases - S shaped (starts off exponential)
slows down due to density-dependent factors

logistic growth

type of population growth that grows faster as the population size increases - J shaped

Exponential Growth

Temperature, light, soil pH, salinity, mineral nutrients

Factors that Affect the Distribution of Plants in the World

biomass

Energy creates ___

biomass of the mass of an organism, find by weighing, and then dehydrating and weighing

dry biomass

biomass of the mass and water of an organism, find by weighing the organism

wet biomass

the degree of variation of life forms within a given ecosystem, biomes or an entire planet
(consists of species richness and species evenness

Biodiversity

amount of different species in an ecosystem

Species richness

how close different populations are in size

species evenness

there are a few dominant species

there is no biodiversity if___

the healthier an ecosystem is

The higher biodiversity is...

organisms that have established themselves in an area where they are not normally found

Alien species