Last 9th grade science test

Topics for June Earth's Resources and Sustainability Overview for Quiz

How and why do populations change over time

Populations change due to variations in birth rates, death rates, immigration, and emigration, which are influenced by limiting factors like resources, predation, disease, and environmental conditions.

Population Ecology

Study of how populations change in size, density, and distribution over time.

Density Dependent

Limiting factors that increase in effect as population size increases (ex

Survivorship Curves

Graphs showing survival rates of individuals in a population over time (Type I, II, III).

Birth Rate

Number of births in a population over a given time period.

K strategist

Species with slow development, few offspring, high parental care, stable populations.

Carrying Capacity

Maximum population size an environment can sustain long

term.

Density Independent

Limiting factors that affect populations regardless of size (ex

Predator Prey Dynamics

Population interactions where predator and prey populations influence each other’s size.

Death Rate

Number of deaths in a population over a given time period.

r strategist

Species with rapid reproduction, many offspring, little parental care, unstable populations.

Limiting Factor

Any biotic or abiotic factor that restricts population growth.

J

Curve growth (exponential)

Rapid population growth under ideal conditions with unlimited resources.

S

Curve growth (logistic)

Population growth that levels off at carrying capacity.

Population Pyramids

Graphs showing age and sex distribution of a population.

Population density

Number of individuals per unit area or volume.

Population growth

Change in population size over time.

How do ecosystems recover after a disturbance like a fire or flood

Ecosystems recover through ecological succession, where species gradually replace one another until a stable community forms.

What is biodiversity and why is it important

Biodiversity is the variety of life in an ecosystem and is important because it increases stability, resilience, and ecosystem health.

Succession

Natural process of ecosystem change and development over time.

Pioneer Species

First species to colonize a disturbed area.

Relative Abundance

Proportion of each species in an ecosystem compared to others.

Mt. St Helen’s Eruption (1980)

Example of a major disturbance used to study ecological succession.

Primary Succession

Ecosystem development in an area with no soil (e.g., after lava flow or glacier retreat).

Climax Community

Stable, mature ecosystem stage after succession.

Species Richness

Number of different species in an ecosystem.

Secondary Succession

Ecosystem recovery after a disturbance where soil remains.

Lichens

Pioneer organisms that help break down rock and form soil.

Biodiversity

Variety of life in an ecosystem, including species, genes, and ecosystems.

I can explain how resources limit a population

Populations are limited when resources like food, water, space, and shelter become scarce. As population size increases, competition increases, slowing growth or causing a decline.

I can define abiotic and biotic factors that determine limiting factors and carrying capacity both qualitatively and quantitatively

Abiotic factors

non

living parts of an ecosystem (temperature, water, sunlight, soil). Biotic factors

living influences (predators, disease, competition). These factors limit population size and determine carrying capacity (K), which is the maximum population an environment can support, often shown on a graph where growth levels off.

I can define and categorize density

dependent and density

independent limiting factors

Density

dependent

depend on population size (competition, disease, predation). Density

independent

affect populations regardless of size (floods, fires, droughts, storms).

I can analyze and interpret population dynamics, graphs, and pyramids (J

curve and S

curve, Boom & Bust)

J

curve (exponential growth)

rapid growth with unlimited resources. S

curve (logistic growth)

growth slows and levels off at carrying capacity. Boom & Bust

rapid population increase followed by a sharp decline when resources run out. Population pyramids

show age structure wide base = growing population, narrow base = declining population.

I can define and describe an organism’s niche within its ecosystem and its importance to ecosystem health

A niche is an organism’s role in its ecosystem (what it eats, where it lives, and how it interacts). Niches reduce competition and help maintain balance and biodiversity, supporting ecosystem stability.

I can describe patterns of human population over time and recognize how technological innovation has caused changes to the human population

Human population has grown slowly for most of history, then rapidly increased due to

Agricultural revolution → more food supply Industrial revolution → improved living conditions and production Medical advances (antibiotics, vaccines) → lower death rates This caused exponential growth and changes in population pyramids (younger populations in developing areas, aging populations in developed areas).

I can explain the difference between primary and secondary succession

Primary succession

starts with no soil (bare rock). Secondary succession

starts with soil already present after a disturbance.

I can describe how an environment recovers after a catastrophic event

After a disturbance, pioneer species colonize first, followed by fast

growing plants, then shrubs and trees. Over time, the ecosystem becomes more complex and eventually stabilizes into a climax community.

I can describe biodiversity

Biodiversity is the variety of life in an ecosystem, including species richness (number of species) and relative abundance (how evenly they are distributed). Higher biodiversity = more stable and resilient ecosystems.