The document discusses ecads (or ecophenes) and ecotypes, which are variations of species influenced by environmental conditions. Ecads are defined as genetically similar organisms displaying morphological differences due to their habitat, while ecotypes are genetically distinct populations adapted to specific environments. The text also explores the types of ecads, their temporary nature, and the process of natural selection leading to the formation of ecotypes and potentially new species.

1. ECADES AND
ECOTYPE
BY-
SNEHA SAHU
M.SC. 3RD SEMESTER IN BOTANY

2. ECADES
•INTRODUCTION
•DEFINITION
•EXPLANATION
•TYPES OF ECADES
ECOTYPE
• INTRODUCTION
•DEFINITION
•ECOTYPE VS. SPECIES
•HOW DID ECOTYPE APPEAR
•FROM ECOTYPE TO SPECIES
•EXAMPLE
Content

3. ECADES

4. INTRODUCTION
• THE ECADS OTHERWISE KNOWN AS ECOPHENES ARE GENETICALLY SIMILAR BUT
MORPHOLOGICALLY DISTINCT IN RESPONSE TO DIFFERENT ENVIRONMENTAL
CONDITIONS.
• GOTE TURESSON (1922), A SWEDISH WORKER CONDUCTED A SERIES OF
EXPERIMENTS ON VARIATIONS WITHIN A SWEDISH PLANT SPECIES PLANTAGO
MARITINA. H
• E FIRST GAVE THE TERM "ECADS" OR "ECOPHENES".
DEFINITION
1.AN ORGANISM OR KIND OF ORGANISM (SUCH AS A SPECIES) MODIFIED BY ENVIRONMENT
2 . A NONHERITABLE SOMATIC MODIFICATION INDUCED BY ENVIRONMENT : AN ACQUIRED
CHARACTER.

5. EXPLANATION
• HE COLLECTED A GROUP OF 20 OR MORE INDIVIDUALS OF THE
SAME SPECIES FROM DIFFERENT AREAS AND PLANTED THEM
UNDER IDENTICAL ENVIRONMENTAL CONDITIONS IN HIS
EXPERIMENTAL GARDEN AT AKARK.
• HE NOTED THAT. SEVERAL INTERGRADING FORMS EXISTED WITHIN
THE SPECIES WHICH DIFFERED FROM ONE ANOTHER IN
MORPHOLOGICAL OR PHYSIOLOGICAL FEATURES AND SOME OF
DIFFERENCES MIGHT BE UNSTABLE AND INDUCED ONLY BY THE
ENVIRONMENTAL FACTORS WHILE SOME OTHERS MIGHT BE
PERMANENT (I.E., GENETICALLY FIXED).

6. CONTI…
• THE POPULATION SAMPLING AND SUBSEQUENT PROCEDURES THAT
TURESSON FOLLOWED LED HIM TO CONCLUDE THAT SPECIES DIFFER FROM
ONE ANOTHER MORPHOLOGICALLY, PHYSIOLOGICALLY AND IN HABITAT
REQUIREMENTS AND ON THE BASIS OF SUCH STUDIES HE PROPOSED THE
FOLLOWING CLASSES OF MORPHOLOGICAL FORMS WITHIN A SPECIES.
• 1. ECADS OR ECOPHENES OR HABITAT FORMS,
• 2. ECOTYPES.
• 3. ECOCLINES,
• 4. ECOSPECIES AND
• 5. COENOSPECIES.

7. CONTI
• ECADS ARE ALSO CALLED EPHARMONES OR HABITAT FORMS WHICH ARE
ENVIRONMENTALLY INDUCED VARIATIONS. THEY BELONG TO THE SAME
GENETIC STOCK OR SPECIES AND THE VARIATIONS IN THEIR MORPHOLOGY (IN
SHAPE, SIZE, NUMBER AND REPRODUCTIVE CAPACITY) ARE INDUCED BY THE
ENVIRONMENTAL INFLUENCES. THE VARIATIONS ARE NOT FIXED BATK ARE
TEMPORARY, SOMATIC AND REVERSIBLE. IF ONE TYPE OF ECAD IS
TRANSPLANTED INTO ENVIRONMENT OF ANOTHER TYPE OF ECAD, THE
DIFFERENCES WOULD DISAPPEAR.
• THESE MORPHOLOGICAL VARIATIONS ARE NOT PERMANENT BECAUSE THE
GENETIC COMPOSITION OF ECADS IS NOT AFFECTED AND SO THEY ARE
IDENTICAL IN THEIR GENETIC BEHAVIOUR AND INTER-FERTILE.
• THE VARIANTS OR ECOPHENES MAY DIFFER TO SUCH AN EXTENT THAT THEY
CAN BE TREATED AS SEPARATE SPECIES. EUPHORBIA PLANTS GROWING IN THE
GRASSLAND ARE PROSTRATE AND PROFUSELY BRANCHED WHILE HE PLANTS OF
THE SAME SPECIES GROWING ON THE FOOTPATHS ARE COMPACT SMALL LEAVES

8. CONTI.
• WHEN THESE FORMS ARE GROWN UNDER IDENTICAL HABITAT CONDITIONS
THEIR DIFFERENCES DISAPPEAR. IN BOTHRIOCHLOA PERTUSA AND
DICHANTHIUM CARICOSUM SEVERAL DISTINCT MORPHLOGICAL FORMS OF
ECADS HAVE BEEN NOTED UNDER DIFFERENT HABITATS BY PANDEYA (1962).
TYPES OF ECADES
IN BOTH THE SPECIES THERE ARE TWO TYPES OF ECADS:
(I) BASKET FORM HABIT SHOWN BY THE PLANTS GROWING IN PROTECTED AREAS,
AND
(II) SAUCER-SHAPED HABIT OF THE PLANTS GROWING IN OVER-GRAZED AREAS.
GRAZING CAUSES REDUCTION IN THE SIZE OF ERECT STEM, NUMBER OF SPIKES PER
RACEME, NUMBER OF SPIKELETS PER SPIKE AND IN LENGTH AND BREADTH OF
LOWER GLUMES OF SPIKELETS.
IN ADDITION TO THESE MORPHOLOGICAL VARIATIONS, SOME PHYSIOLOGICAL
VARIATIONS ARE ALSO NOTICED, AS FOR EXAMPLE DEVELOPMENT OF
ANTHOCYANINE IN THE LEAVES AND EARLY INITIATION OF FLOWERS.

9. ECOTYPE

10. INTRODUCTION
• GENETICALLY RACE WITHIN A SPECIES, WHICH ISK IT DESCRIBES
DISTINCT GEOGRAPLUE A VARIETY.
• POPULATION OR GENOTYPICALLY ADAPTED TO SPECIFIC
ENVIRONMENTAL CONDITIONS. TYPICALLY, THOUGH ECOTYPES
EXHIBIT PHENOTYPIC DIFFERENCES (SUCH AS IN MORPHOLOGY OR
PHYSIOLOGY) STEMMING FROM ENVIRONMENTAL HETEROGENEITY,
THEY ARE CAPABLE OF INTERBREEDING WITH OTHER
GEOGRAPHICALLY ADJACENT ECOTYPES WITHOUT LOSS OF
FERTILITY OR VIGOR.

11. DEFINITION
• AN ECOTYPE IS A POPULATION OF SPECIES THAT DIFFERS
GENETICALLY FROM OTHER POPULATIONS OF THE SAME SPECIES
BECAUSE LOCAL CONDITIONS HAVE SELECTED FOR CERTAIN
UNIQUE PHYSIOLOGICAL OR MORPHOLOGICAL CHARACTERISTICS.
• BROADER THAN A BIOTYPE AND NARROWER THAN SPECIES.
ECOTYPE
•WHILE SPECIES ARE A MORE BROAD CATEGORY, ECOTYPES ARE
NARROWED DOWN MORE SPECIFICALLY.
•THESE SPECIFICS CAN INVOLVE AREA OF GROWTH, A PARTICULAR
PHOTO PERIOD, STRUCTURE, ETC. (SOURCE: LIFE: THE SCIENCE OF
BIOLOGY)

12. HOW DID ECOTYPE APPEARS
• ECOTYPES APPEARED IN RESPONSE TO A
PROCESS OF NATURAL SELECTION WITHIN
SPECIES. •
• IN ORDER TO MORE EFFECTIVELY SURVIVE
WITHIN A SPECIFIC CLIMATE, REGION, ETC;
ECOTYPES DEVELOPED.
• FROM ECOTYPE TO SPECIE’S
• AN ECOTYPE MAY BECOME A SPECIES IF
NATURAL SELECTION LEADS TO FURTHER
VARIATIONS WITHIN ITSELF
• IN THIS CASE, THE ECOTYPE WOULD
TAKE THE FORM OF A NEW SPECIES AND
ITS VARIATIONS WOULD BE NEW

13. EXAMPLE