Topic 4- Notes Flashcards
Definitions:
i) Autotroph
ii) Heterotroph
iii) Environment
iv) Habitat
i) Organisms that are able to produce their own complex molecules
ii) An organism getting its nutritional requirements from complex organic molecules. (opposite of autotroph)
iii) All the conditions that effect a population (e.g. competition - biotic and abiotic - physical e.g. weather_. Not the same as habitat.
i) cell wall
ii) species
i) structure surrounding cell membrane that supports and strengthens the cell. In plant cells, made of cellulose. In bacteria, made of chitin.
ii) All members of the species can interbreed with members of their species and they produce viable and fertile offspring. Each species has a characteristic genome. - share the same gene pool. - no 2 species can occupy the same niches.
i) Decay/decomposition
ii) Biomass
iii) Massive
i) The breakdown of organic compounds (by bacteria an fungi) produces CO2.
ii) measure of energy. The dry mass (H20 has no energetic value) of a population or trophic level in a given area (eg Kg/m2/yr) reflects the energy stored..
iii) has a big mass.
i) organic
ii) Nitrogen-fixing bacteria
iii) Niche
i) All compounds of carbon are organic except:-
CO, CO2 and all carbonates (these are all inorganic)
ii) Turn nitrogen gas into soluble nitrates.
iii) How a population exploits its environment. The relational position (trophic level) of a population n an ecosystem. i.e. the ‘occupation’ not just the ‘address;.
iv) Changes in the behaviour, physiology and anatomy of a species to enable it to successfully exploit it’s environment.
i) Selection pressure
ii) Natural selection
iii) Phylogeny
i) A factor in the environment which leads to certain traits being more beneficial to survive than others.
ii) The theory that best explains evolution. Changes in the environment result in individuals being better suited to their environment (variation) than others and therefore more likely to survive and reproduce. A cause for evolution.
i) Evolution
ii) biodiversity
iii) ecology
i) A gradual process over many generations, leading to changes in phenotype (and genotype) and possibly the appearance of new species (speciation).
ii) The degree of variation of life - comprising:
Richness - the variety of different species.
Abundance - high no. individuals of each species.
Biodiversity hotspots = a region which contains at least 0.5% or 1500 species of endemic plants.
iii) The study of the relationships between organisms and their environment.
i) Ecosystem
ii) Endemism
i) A stable community of species arranged in trophic levels interacting with each other and with the environment (including all abiotic components) characterised by the flow of energy and the recycling of nutrients. Energy flows up an ecosystem.
Every ecosystem must have an autotroph.
ii) The concept that a species is unique to a defined geographic location and s exclusively found there. A native species is one that’s considered to have been endemic for a relatively long period of time.
i) Community
ii) Population
iii) Richness
iv) Abundance
v) Hierarchial
i) several populations
ii) a group of organisms that belong to the same species
iii) no. different species
iv) no. individuals
v) descending order of nested groups (taxon) with the largest group at the top of the order.
Classification:
i) Binomial
ii) Hierarchy
i) Genus and speies
ii) Describes the arrangement of biological species into nested groupings.
What is a niche?
If 2 species live in same habitat, have same role, food source, time of feeding and same shelter site…. they occupy the SAME NICHE!
the BETTER-ADAPTED organisms will out-compete the others and exclude it from the habitat.
e.g. Red squirrel was out - competed by grey-squirrel
Examples of niches:
e. g. orchid niches
e. g. woodpecker niches
- exploit behaviour of insects (bees carry pollen to other orchids)
- pyramidal orchids attract insects with scent. e.g. collar shaped pollen parcel attaches w/quick drying glue around moths tongue.
- some can only be pollinated by one species. insect.
- some mimic female insects
- powerful beak
- v long tongue
- each have diff. niches so co-exist in same habitat
What is:
i) co-adaption and
ii) the meaning of ADAPTED?
i) When 2 species evolve in tandem and are dependant on each other e.g. Brazil nut and the orchid Bee.
ii) means being specialised to suit the environment in which the organisms live. Adaptations are features that enable an organism to survive.
What is a
i) behavioural
ii) physiological and
iii) Anatomical adaptions?
i) actions by organisms that help them to survive/reproduce. e.g. plants turn their leaves towards the sun.
ii) features of the internal workings of organisms that help them to survive/reproduce e.g. Danish scurvy grass adapted to tolerate high salt conc. therefore can grow on side of roads.
iii) Structures we can see when we observe/dissect an organism e.g. bodies of bumblebees show adaptions used to collect nectar/pollen.
What is the molecular account of natural selection?
i) a population has some naturally -occurring genetic variation with new alleles created through mutations.
2) A change in the environment causes a change in the selection pressures acting on the population.
3) An allele that was previously of no particular advantage now becomes favourable.
4) Organisms with the allele are more likely to survive, reproduce and so, produce offspring.
5) Their offspring are more likely to have the allele, so it becomes more common in the population.
Describe:
i) stabilising selection
ii) a gene pool!!
i) Natural selection often (but not always) leads to the disappearance of extreme phenotypes.
ii) members of a species share a gene pool
- a gene pool consists of all the alleles of all the genes present in a population
Kingdoms
What are some features of:
Animalia
- Heterotrophic, relying on other organisms for nutrition
- Includes phyla such as jellyfish, round worms, arthropods and molluscs
- No cell walls or large vacuoles
- Most can move from place to place and have nervous co-ordination
- Cannot photosynthesise
- Multicellular eukaryotes with differentiated cells organised into specialised organs.
Plantae
- Includes mosses, liverworts, ferns, conifers and flowering plants
- Multicellular eukaryotes with differentiated cells organised into specialised organs.
- Cells contain chloroplasts and large vacuoles
- Cell walls contain cellulose
Fungi
- Most are made up of a network of thread-like strands, called multinucleate hyphae
- Cell walls made of the polysaccharide chitin
- heterotrophic - most absorb nutrients from decaying matter after extracellular digestion
- Cannot photosynthesise
- Includes moulds, yeasts and mushrooms
- Multicellular and unicellular eukaryotes
Protoctista
- Multicellular eukaryotes (although most do not have separate cells). But yeasts also belong to this group and they are unicellular.
- Includes single-celled protozoa, such as amoeba and paramecium, and algae.
- Basic body structure is relatively simple
- May either photosynthesise or feed on organic matter from other sources.
Prokaryotae
- Make organic compounds by photosynthesis (except for a few parasites)
- Includes the bacteria and blue-green bacteria (cyanobacteria)
- Cells do not have organelles, such as mitochondria or chloroplasts.
- Cells have no distinct nucleus. the nucleic acid is in a single circular chromosome.
- Cells are very small, typically less than 10um across.
Example of classification:
Lions
Kingdom - Animalia (all animals) Phylum - Chordata (all verterbrates) Class - Mammalia (all mammals) order - Carnivora (meat eaters) Family - Felidae (cats) Genus - Panthera (roaring cats) Species - Leo (lions) King Philip called out for Gold Stars
humans
Kingdom - Animals Phyla - Chordates Classes - mammal Orders - primates Families - homonids Genera - homo species - homo sapiens Genera and species are a unique name binomial system
Definitions A - Taxonomy B - Taxons C - Dichotomous keys D - phylogeny E - speciation
A - the science of classification B - classification groups C - A series of questions to which there are only 2 answers used to classify and name organisms D - evolutionary history E - the formation of new species
Describe Hardy - Weinburg and conditions
- used to calculate allele frequencies
- need to know the homozygous recessive
- Allele frequencies are constant if:
- there’s no natural selection
- no mutations
- no movement (in/out of population)
- mating is random
p2 + 2pq + q2 = 1
p + q = 1
dominant recessive
Examples of classification
- criteria
- analagous
- 5 kingdom system, 3 domain system, phylogenetic diagrams.
- criteria:
i) anatomy
ii) physiology
iii) behaviour
iv) genetic make-up
v) evolutionary relationship to other organisms - organisms with similar anatomies aren’t necessarily closely related. e.g. shark and dolphin streamlined shapes are merely analagous because they both live in water.
Sources of genetic diversity:
Allows population to adapt to changing conditions and so should be conserved.
A pop. declines - some alleles may be lost - genetic diversity.
Mutations: source of new genetic material.
Meiosis
Prep. for sexual reproduction: independent assortment/crossing over.
1 gamete from each parent/diff. combination alleles.
Fertilisation - random (which egg/sperm?)
- mate selection (which 2 parents)
Expression of genotype - dominant allele mask recessive ones.
Describe 2 types of mutations:
Gene (point) mutations:
alterations of the DNA base sequence. may arise during DNA replication or another stage of the cell cycle.
Chromosome mutations:
Small sections of chromosome may be re-arranged during meiosis; they may be inverted, moved from one chromosome to another or even lost.
A What are biodiversity hotspots?
B How can you measure genetic diversity within a species?
A - areas of particularly high biodiversity.
B - directly/indirectly
1) direct - DNA sequencing to determine the bases in a segment of DNA and to determine which alleles are present.
2) or DNA can be cut into fragments and then separated using electrophoresis. Alleles produce fragments of different lengths.
Definitions/Functions:
a) tonoplast
b) chromatin
c) nuclear envelope
d) amyloplasts
a) vacuolar membrane - controls ionic movement in and around the cell . Regulate water flow in and out of the vacuole.
b) to package DNA - to strengthen DNA to promote mitosis/meiosis and prevent DNA damage.
c) made of lipids and encases the genetic material (nucleus)
d) storage vacuoles in the cytoplasm
Label the diagram:
Dicot Monocot
cotyledon (embryonic leaves) A B
vascular bundles C D
secondary growth E F
leaf veins G H
example I J
Dicot Monocot
A 2 B 1
C in a ring D scattered
E frequent F rarely
G parallel H reticulated
I peas/tomatoes/roses J grasses
What are parenchyma (tissue) ?
Structure: Large, thin walled, unspecialised
Function: Packing and storage
Location: Most parts of the plant, especially stem
What are collenchyma (tissue) ?
Structure: elongated cells running parallel to the length of organs that it’s found in. Collenchyma cells have thick cellulose walls which thickened at the corners.
Function: cells contain living cytoplasm and they sometimes contain chloroplasts. Collenchyma serve as supporting and strengthening tissue.
Location; Collenchyma tissues are mainly found under the epidermis in young stems in the large veins of leaves.
What are sclerenchyma (tissue)?
Structure: Hard, woody cells. Mature s.cells are dead cells that’ve heavily thickened wall containing lignin fibres are greatly elongated cells whose long, tapering end interlock sclereids are extremely variable in shape
function: Support.
Location: Fibres found all over in plant body, stem, roots and vascular bundles in leaves. Sclerids are present in various tissues of plant e.g. cortex, pith , xylem and phloem.
What is the cohesion - tension theory of transpiration?
- Water evaporates from surface of epidermal cells.
- Water vapour diffuses - out stoma from substomatal cavity.
- Water evaporates from surfaces of cells.
- H2O diffuses through plasmodesma between cells (symplast)/diffuses along cell wall (apoplast)
- Water leaving leaf cells creates conc. gradient draws up H2O
- lower osmotic pressure in leaves - low/-ve pressure in xylem.
- water enters xylem via apoplastic pathway and symplastic pathway
- casparian bands prevents apoplast movement from endodermis to pencycle
- water uptake by osmosis - mostly into root hair cells.
What is cohesion and adhesion?
What are the 3 basic principles plants use to build tall structures.
Cohesion: H-bonds between H2O molecules
Adhesion: H-bonds between H2O and cell wall - cause surface tension.
- produce strong cell walls out of cellulose, a polymer made from sugar molecules
- they build columns and tubes from specialised cells.
- stiffen some of these special cells with another polymer called lignin
