QCE Unit 3 Biology

What are the 2 methods of reproduction?

1. Asexual

2. Sexual

Describe 4 features of Linnaean system.

1. Based on physical features and reproductive methods (plants)

2. Hierarchy of groupings (taxa)

3. Subdivision (sub-species)

4. Binomial nomenclature (scientific naming)

Rank taxonomic levels in the Linnaean system and list key information for levels.

Domain- Archaea, Bacteria, Eukarya

Kingdom- Monera (prokaryote), Protista, Fungi, Plantae and Animalia (eukaryotes)

Phylum- fish, mammals, birds, reptiles, amphibians

Class

Order

Family

Genus- Binomial nomenclature

Species- Binomial nomenclature

Describe the 4 asexual methods of reproduction.

Binary fission: division of a cell into 2 identical daughter cells

Budding: new cell grows out of the body of a parent

Fragmentation: parent breaks into parts that regenerate into whole individuals

Parthenogenesis: growth and development of an embryo without fertilisation (in some invertebrates and most plants)

What are the limitations of the Linnaean system?

It is not based on molecular evidence but rather physical similarities.

List the 5 morphological features used in classification

1. Homologous structures

2. Analogous structures

3. Vestigial structures

4. Comparative embryology

5. Geographic distribution

Homologous structures

Structures in different species that are similar but with a different function (common ancestry) (divergent evolution)

Analogous structures

Body parts that share a common function, but different structure (convergent evolution)

Vestigial structures

A structure with no apparent function

Comparative embryology

The formation, early growth, and development of different organisms while developing similarities.

geographic distribution

example: fossils

Sexual reproduction

Meiosis: fertilisation using gametes

What is the purpose of the Classification system?

Allow scientists to see relationships between different species.

Define phylogeny

Evolutionary history of a species.

Define molecular phylogeny

Evolutionary history of species using DNA sequencing.

Define clade

Section of phylogenetic tree- group of organisms with common ancestor and lineal descendants.

What type of DNA is used for molecular phylogeny and why?

Mitochondrial DNA is used because the maternal line is easier to track mutations and rate.

Define cladistics

Classification system according to derived characteristics (anatomical, physiological, behavioural and genetic)

What are some common assumptions for cladistics?

1. Shared common ancestor

2. bifurcating pattern: when lineage splits into 2

3. Physical change

What does a node represent?

Each node on a cladogram and phylogenetic tree represents a common ancestor.

Define ecology

The study of interactions between organisms and their environment

Define ecosystem

A community and its abiotic environment

What is the difference between abiotic and biotic factors

Abiotic: non-living chemical or physical part of environment

Biotic: living part of environment

Define biosphere

The regions of the surface, atmosphere, and hydrosphere of the earth occupied by living organisms.

Define community

Interacting group of various species in a particular area

Define population

A group of organisms of the same species who live in the same area at the same time.

Define producers

The base of all food chains. Converts inorganic chemicals into food.

Define consumers

Organisms that eat another organism for nutrition

Define heterotroph

An organism that cannot make its own food. Eats other living things

Contrast herbivores, carnivores, omnivores and detritivores

Herbivore: plant eating organism

Carnivore: meat eating organism

Omnivore: meat and plant eating organism

Detritivore: detritus eating organism

Define decomposer

Organism that breaks down and obtains energy from dead organic matter.

Parts of an ecosystem

Microhabitat--> Habitat--> Ecosystem--> Biome

Habitat vs Microhabitat and example of each

Habitat: the environment where an organism or species lives eg. coral reef

Microhabitat: small specific living space within a larger habitat eg. anemone where clown fish live

Define biodiversity

The variety of life in the world or in a particular habitat or ecosystem. The different plants, animals and micro-organisms and the genetic information they contain and the ecosystems they form.

Explain 3 levels of biodiversity

1. Genetic diversity: the variety of genes within a species

2. Species diversity: the variety of species within region/habitat

3. Ecosystem diversity: the variety of ecosystems in a given place

Explain the term species

Group of similar organisms that can interbreed and produce fertile offspring.

Why is it important to define species?

You can only protect what you can recognise.

Give example of an interspecific hybrid with a infertile offspring.

Horses can breed to donkeys to produce Mules which are infertile.

Compare the terms distribution and abundance

Distribution

- Area where organisms are found

- Refers to the way organisms are arranged in an area

- Affected by abiotic factors

Abundance

- The number of individuals of a species in a given area.

- Defined as density

- Largely influenced by biotic factors

Compare Species richness to Species evenness.

Species richness is the no. of individuals of a particular species in the area sampled and species evenness is a measure of abundance in relation to the total number of individuals of all species in the area.

Define Percentage cover and what is it used for?

It's the measurement of the proportion of an area covered by an organism. It's used for calculating abundance and estimating the distribution of plants in a particular area but can be used for other organisms. It also gives an indication of the influence a species has in an area.

Quadrat

Used to calculate percentage cover.

Simpson's Diversity Index (SDI)

A measure of species richness and evenness showing the probability that two randomly selected individuals will be different species.

Low species diversity vs high species diversity

Low

- few successful species in habitat

- environment is stressful with few ecological niches and few organisms are well adapted to that environment

- simple food webs

- change in environment would probably have quite serious effects

High

- more successful species and more stable ecosystem

- environment less hostile and more ecological niches available

- complex food webs

- environmental change less likely to damage ecosystem as a whole

Purpose of field sampling

To gather information about its population and environment including;

- population estimation

- density

- distribution

- environmental gradients and profiles

- zonation and stratification

Stratified sampling is conducted through considered...

(hint: there are 4 steps)

- Site selection

- Choice of ecological surveying techniques

- Methods to minimise bias

- Presentation and analysis of collected data

Purpose of stratified sampling

- To identify individual species in ecosystem

- Consider interactions with abiotic and biotic factors in an ecosystem/ habitat/ microhabitat

- Enables ecologists to divide large population into sub-groups/strata

Give examples of 3 different strata in a rainforest

1. Canopy

2. Understorey

3. Ground cover vegetation

List advantages of stratified sampling

- Reduces sampling error

- Ensures greater level and adequate representation of all subgroups

Zonation

- Community pattern in which there is a visible strata or zones caused by changes in abiotic and biotic factors.

- Zonation is found where conditions vary greatly over a short distance.

Usefulness of transects and 2 types of transect techniques.

- Useful for determining distribution

- Line and Belt

Usefulness of quadrats and list types of sampling distribution

- Useful for sampling animals that are not mobile and plants. Sample size is important to minimise error

- Types: Evenly spaced, Random (chance), Zoned (clustered)

List 4 ways of minimising bias

1. Law of large numbers: greater the sample size, more likely sample mean will represent entire community

2. Random number generator: avoid bias in site selection for quadrat sampling

3. Counting criteria: parameters to determine if organism is in or out of quadrat avoids variation

4. Calibration of equipment: data loggers must be cleaned and checked

Symbiosis

A relationship in which two different organisms live in close association with each other

List the 4 different symbiotic interactions and give example for each

Mutualism: sea anemone + clown fish (+,+)

Commensalism: whale + barnacle (0,+)

Parasitism: dog + tick (-,+)

Amensalism: cattle trampling grass (0,-)

How do ecosystems change over time?

-Introduced species

-Habitat change

-Climate change

-Overpopulation

-Pollution

-Disease

-Succession

Define succession

The change in structure and species composition of a community over time

Climate related abiotic factors

- Temperature

- Water

- Radiant energy

- Humidity

- Wind and air currents

Soil related abiotic factors

- pH

- Mineral salts/trace elements

- Water retention

Geographic abiotic factors

- Water currents

- Salinity

- Topography

- Shelter

Define temporal scales and provide an example

Changes within an ecosystem over time.

Example: Rocky shores will have drastic changes throughout day.

Explain temporal changes in a rocky shore

changes such as temperature variation, salinity variation, time exposed to air, competition and amount of sunlight at different times of day in accordance to the different tide zones.

What influences spatial changes?

Changes in an ecosystem over a given space.

Influenced by;

- changes in abiotic factors

- changes in biotic distribution

- human interference

2 types of competitions on populations within ecosystems and their consequences

Interspecific competition: organisms from different species compete for the same resource. Consequences: Reduced population sizes (possibly extinction), species outcompeting each other (altering species distribution).

Intraspecific competition: organisms from same species compete for the same resource. Consequences: Fluctuation in population size around the carrying capacity.

primary succession

An ecological succession that begins in an area where no biotic community previously existed (no soil is present)

secondary succession

Succession following a disturbance that destroys a community without destroying the soil

Predation

An interaction in which one organism kills another for food.

competition

A common demand by two or more organisms upon a limited supply of a resource; for example, food, water, light, space, mates, nesting sites. It may be intraspecific or interspecific.

Cladogram

A diagram that is based on patterns of shared, derived traits and that shows the evolutionary relationships between groups of organisms

disease

An abnormal state in which the body is not functioning normally

old-growth forest

complex forest that has developed over a long period of time and is relatively untouched by human activity

coral reef

A structure of calcite skeletons built up by coral animals in warm, shallow ocean water.

Productive soils

fertile soil that can produce, support, and grow plants in it

limiting factor

Any biotic or abiotic factor that restricts the existence, numbers, reproduction, or distribution of organisms.

optimum tolerance range

a set point of ideal conditions, with a range that an organism can tolerate.

food chain

series of steps in an ecosystem in which organisms transfer energy by eating and being eaten

food web

A community of organisms where there are several interrelated food chains

energy transfer

the transfer of energy from one organism to another through a food chain or web

Biomass

the total mass of organisms in a given area or volume.

trophic level

Each step in a food chain or food web

trophic pyramid

A representation of the distribution of biomass, numbers, or energy among trophic levels

Efficiency of energy transfer

The percentage of energy passed from one trophic level to the next

carbon cycle

the movement of carbon from the nonliving environment into living things and back

nitrogen cycle

The transfer of nitrogen from the atmosphere to the soil, to living organisms, and back to the atmosphere

nitrogen fixation

process of converting nitrogen gas into nitrogen compounds that plants can absorb and use, performed by nitrogen-fixing bacteria

Denitrification

process by which bacteria convert nitrates into nitrogen gas

water cycle

The continual movement of water among Earth's atmosphere, oceans, and land surface through evaporation, condensation, and precipitation

ecological niche

A specific role of a species within an ecosystem, including its use of resources, and relationships with other species.

competitive exclusion principle

Ecological rule that states that no two species can occupy the same exact niche in the same habitat at the same time

Population

A group of individuals that belong to the same species and live in the same area

keystone species

a species that has an unusually large effect on its ecosystem

carrying capacity

Largest number of individuals of a population that an environment can support long-term

limiting factor

Any biotic or abiotic factor that restricts the existence, numbers, reproduction, or distribution of organisms.

population growth rate

(births + immigration) - (deaths + emigration) / total population x 100

population change

(births + immigration) - (deaths + emigration)

Lincoln Index

a method for determining population size by marking and recapturing portions of a population

Lincoln index formula

N = Mn/m

population growth models

exponential (J curve) and logistic (S curve)

population limiting factors

biotic factors — competition for resources, predation and disease

abiotic factors — space, availability of nutrients, pollution, natural disasters, extreme climatic events (drought, cyclones, global temperature change).

sere

refers to a series of ecological communities formed in ecological succession