Biology Module 4 - Ecosystem Dynamics

Gene Pool

All the genes in all the members of a population. Immigration INCREASES gene pool; emigration DECREASES it

Evolution

The gradual change in the frequency of genes in a gene pool

Population sampling

Selecting a small sample of the population to get the gene frequencies of the entire population

Mutations

Inheritable changes in DNA.

Natural Selection

Primary reason for EVOLUTION

Adaptations

Inherited traits that improve the chance of survival and reproduction

Ecology

Study of interactions between organisms and their environment

Biotic

Living things. Plants & animals

Abiotic

Non - living things. Water, sunlight, temperature, pH...

Habitat

Where an organism lives. (a tree, water, forest...)

Niche

The role (job) of an organism. Two organisms can occupy the same habitat if they have different niches

Population Density

The number of organisms/ area. PD = N/Area

Population Growth Rate

The change in number of organisms over time. GR = N/T (most recent data first)

Dynamic Equilibrium

Present in mature ecosystems. Same as homeostasis.

Environmental Resistance

All factors that limit population growth - biotic and abiotic.

Limiting factors

Environmental resistance. Can be density dependent (biotic) - disease, starvation or density independent (abiotic)- fire, flood.

Predator-prey cycle

More prey than predators. Prey #s increase before predators do.

Interspecific competition

Between members of different species

Intraspecific competition

Between members of same species

Competition consequence

If 2 species occupy the same niche, one will be eliminated

Symbiotic Relationships

Relationships between species. 3 types: Mutualism, Parasitism and commensalism

Mutualism

Both benefit. Ex. bees and flowers

Parasitism

One benefits, other harmed. Parasites: mosquitos, lice, round worms . Hosts: larger species

Commensalism

One benefits, other is unaffected. Buffalo and birds

Ecological Succession

Gradual change over time.

competition

the struggle between organisms to survive in a habitat with limited resources

Symbiosis

A close relationship between two species that benefits at least one of the species.

disease

An abnormal state in which the body is not functioning normally

Sampling Techniques

techniques used to collect samples, for example random sampling, systematic and stratified sampling

Ice core drilling

long cylinders of ice are extracted where each layer is identified as a season. Can contain dust from volcanic eruptions or changes in beryllium concentration from solar radiation.

radiometric dating

the process of measuring the absolute age of geologic material by measuring the concentrations of radioactive isotopes and their decay products

Gas analysis

A technique that can be used to tell us about past climates e.g. temperatures by determining levels of gases

Human induced selection pressures

Ranging from fisheries, trophy-hunting, poaching, domestication, climate change and pollution.