B1 Flashcards
Biotic
Living things
Abiotic
Non living things
Individuals/Species
A single organism
Population
A group of individualds from the same species that can reproduce
Community
The interaction of different populations
Ecosystem
A community and its physical and chemical environment
Ecotones
Transition area between ecosystems where organisms from both ecosystems interact
Organisms can move back and forth between ecosystems
- Greater biodiversity ➡ More stable
- Edges = More diverse
Ecological Niche
An organism’s role in an ecosystem
Each species tends to have a different niche
- Place in food web
- Habitat
- Breeding area
- The time of day at which its most active
Ecological Niche
Owl vs Hawks.
(DO NOT need to memorize - Just an example)
- Feed on similar organisms
- Occupy different niches ➡ Non competing
Do not compete with each other to obtain resources
Terrestrial Niches
Helps us understand how organisms in an ecoystem interact with each other
Ecological Niche of a Population
The role its members play in a ecosystem
Aquatic Niches
Great White Shark
(DO NOT need to memorize - Just an example)
- Place in food web - Top predator
- Habitat - Temperate costal waters
- Breeding Areas - Warm temperate and subtropical
- Time of day its most active - Dusk and dawn
New (exotic) species
New species can cause disturbance
Start competing for a niche with 1+ species
How do new exotic species arrive
- Natural movement
- Seed dispersal
- New routes
- Human introduction
Effects of new exotic species
Major cause of species depletion, extinction, habitat loss
Because of:
* No natural population control
* Native species can’t compete
* Prey lack defense mechanisms
Biome
A large geographical region with a specific climate and the organisms that are adapted to that climate
4 Major Terrestrial Biomes in Canada
- Tundra
- Taiga
- Temeprate Deciduous Forest
- Grassland
2 Major Aquatic Biomes in Canada
- Freshwater (lake,river,pond ecosystems)
- Marine (ocean ecosystems)
Abiotic Factors of Aquatic Ecosystems
- Temperature
- Sunlight
- Dissolved O2 (Colder water can hold more O2)
- Depth
- Light
- Clarity
- Dissolved Nutrients
- Salinity
- pH
Littoral Zone
Area from the shore of a lake or pond to the point where no more plants grow in the lake bottom
Limnetic Zone
Area of a lake or pond in which there is openw ater and sufficent light for photosynthesis to occur
Profundal Zone
Region of a lake beneath the limnetic zone, in which there is insufficient light for photosynthesis to occur
Benthic Zone
The lowest ecological zone in a water body, and usually involves the sediments at the seafloor
Productivity
Rate of which producers capture/store energy
Seasonal Variations
Fall
- Surface water cools ➡ Water becomes more dense ➡ sinks with O2 (fall turnover)
- When the water becomes cooler than 4 °C the layer reforms for winter
Seasonal Variations
Winter
- Ice layer can form on top
- Photosynthesis can occur if light can penetrate ice layer (O2 high)
Seasonal Variation
Spring
- Ice melts ➡ O2 exchange at surface
- Warming of surface water ➡ sinks➡ takes O2 to deeper layers
- Warm water sinks ➡ deep water pushed to surface (spring turnover)
Stratification
More lught is absorbed at shallow depths, which means heat is retained in the surface level. This density gradient seperates the lake into 3 layers
Occurs due to temp. and salinity gradients
Epilimnion
Surface layer which is less dense, absorbs more light and heat
Nutrient Availibility
Oligotrophic Lake
- Low nutrient levels
- Photosynthesis-limited (less producers)
- Clear water
- O2 rich
Nutrient Availibility
Eutrophic Lake
- High nutrient levels
- High photosynthesis
- Murky water
- O2 poor
Soil Layers
Litter
Upper layer made up of partially decomposed leaves/grasses
Soil Layers
Topsoil
Beneath litter made up of small rocks and decaying plant and animal matter (humus = nutrient rich)
Soil layers
Subsoil
Beneath topsoil made up of rock particles and small amounts of organic matter
Soil layers
Bedrock
Layer of soil that marks end of soil
Water table
Boundary between groundwater and soil that is unsaturated with water
Groundwater
Water in soil
Limiting Factor
Anything that slows a population’s growth
Biotic limiting factors
- Competition for resources
- Predation
- Parasites/disease
Interspecific competition
Between 2 different species
Intraspecific competition
Between the same species
Abiotic limiting factors
- Water
- Temperature
- Sunlight
- O2
Genetic Diversity
IB
Amount of variation in inherited traits between individuals of the same species
Species Diversity
IB
Number of different species
Taxonomy
IB
Classification system that infers relationships among organisms
Helps us to:
* Identify organisms
* Recognize similarities between groupings of organisms
The Three Domains
Eukaryote
IB
- Uni and multicellular
- Sexual reproduction
- Phenotypes and nutrition are diverse
- Each kingdom has specializations
The Three Domains
Archaebacteria
IB
- Prokaryotes: unicellular
- Asexual reproduction
- Chemoautotrophic or heterotroph
- Extreme environments
The Three Domains
Eubacteria
IB
- Prokaryote; unicellular
- No membrane bound nucleus
- Asexual reproduction
- Mixotrophic
- Variety of environments
Bacteria that:
* Fix nitrogen
* Help you digest
6 Kingdoms
Archaea
IB
Single-celled prokaryotic organisms that live in extreme environments
6 Kingdoms
Bacteria
IB
Single-celled prokaryotic organisms that live in a wide range of habitats
6 Kingdoms
Protista
IB
Consists of both single and multi-celled eukaryotic organisms
6 Kingdoms
Fungi
IB
Single and multi-celled eukaryotes that secrete enzymes to digest their food
6 Kingdoms
Plantae
IB
Eukaryotic multi-celled organisms that use photosynthesis
6 Kingdoms
Animalia
IB
Eukaryotic multi-celled organisms that are heterotrophs
Phylogeny (history of evolution)
IB
Shows the relationship between organisms. Starts with ancestral form and include branchings that lead to all of its descendants
Dichotomous Key
IB
Two-part key used to identify living things - figure out the species of an organism
Often done by physical characteristics
Natural classification system
IB
Classify group organisms according to evolutionary relationships
Artificial classification
IB
Classify group organisms based on non-predictive features;
* Do not consider species relatedness
* Easy to develop
* Not often used
Phylogenetic Classifications
IB
Differenciate organisms based on genetic features
2 Advantages of Natural Classification
IB
- Identification of species is easier
- Can predict the characteristics of species within a group. This is because all members of the group have evolved from a common ancestral species
Doman: Archaeabacteria
Kingdom: Archaea
IB
- Oldest type of life on Earth
- Mostly autotrophic but some are heterotrophic
Domainl: Eubacteria
Kingdom: Bacteria
IB
- Unicellular
- Asexual reproduction
- Mixotrophic
- Exist in both aerobic and anaerobic environments
Domain: Eukarya
Kingdom: Protista
IB
- Mostly unicellular, can be multicellular
- Autrotrophs, heterotrophs or decomposers
Domain: Eukarya
Kingdom: Plantae
IB
- Photoautotrophic
- Doesn’t move
- Cellulose wall
- Multicellular
Domain: Eukarya
Kingdom: Animalia
IB
- No cell wall
- Multicellular
- Heterotrophic
Bryophytes - Mosses/liverworts
IB
- Does not have “true” roots, leaves or stems
- Anchored by rootlike structures called rhizoids
- Lack vascularisation
- Reproduce via pores
Filicinophyta (Ferns)
IB
- Have leaves, roots, stens, leaves, are pinnate
- Have vascular system
- Reproduce via spores
Coniferphytes - Woody trees and shrubs
IB
- Leaves, roots stems
- Stems are woody, leaves are waxy and needle-like
- Have vascular system
- Produce via non-motile seeds (found in cones)
Angiospermophyta - Flowering plants
IB
- Have leaves, roots, stems
- Highly variable in structure
- Vascular system present
- Reproduces via seeds in ovules which are in flowers or fruits
Porifera - Sea sponge
IB
- Aymmetrical
- No mouth or anus
- Silica or calcium carbonate based spicules to provide structural support
- Sessile
Cnidaria - Anemones, coral, jellyfish
IB
- Radial body symmetry
- Mouth but no anus
- May have tentacles with stinging cells; uesd for capturing and disabling prey
- Corals secrete calcium carbonate skeleton
Platyhelmnithes - Flatworms
IB
- Bilateral body symmetry
- Mouth but no anus
- Flattened body shape (high SA:V ratio)
- May be parasitic and live within host organisms
Annelida - Earthworms and leeches
IB
- Bilateral symmetry
- Seperate mouth and anus (connect through gut)
- Ringed segments
- Peristaltic contraction of segments
Mollusca - Slugs, squids, bivalves
IB
- Bilateral body symmetry
- Seperate mouth and anus (connect through gut)
- Visceral mass, muscular foot and mantle
- Diverse in size and anatomical structure
Arthopoda - Spiders and scorpions
IB
- Bilateral body symmetry
- Seperate mouth and anus (connect through gut)
- Joined body secretions and appendages
- Hard chitinous exosleletons
- > 80% of all known living animal species
Chordata - Vertebrates
IB
- Bilateral body symmetry
- Seperate mouth and anus (connect through gut)
- Notochord, hollow, dorsal nerve tube, develop into backbone (spine)
- Some subphyla are invertebrates
Cladistics
IB
Determination of evolutionary relationships based on common features
Clade
IB
A group of organisms that have evolved froma common ancestor
Species can evolve over time and split to form new species
Homologous Traits
IB
- Same anatomy; different function
- Share common ancestry
- Arise via divergent evolution
Analogous Traits
IB
- Different anatomy; same function
- Do not share common ancestry
- Arise via convergent evolution
Molecular Clock
IB
DNA and protein sequences evolve at a rate that is relatively constant over time and among different organisms
Mitochondrial DNA
- Only inherited maternally
- Does not go meiotic recombination
- More copies per cell
- Higher mutation rate
Therefore: Ideal for comparisons of species that diverged recently
